[Csnd] Simplistic approximation of air absorption (cutoff frequency)

[Csnd] Simplistic approximation of air absorption (cutoff frequency)

Date	2021-09-08 17:39
From	"Jeanette C."
Subject	[Csnd] Simplistic approximation of air absorption (cutoff frequency)
	Hey hey, I am looking at acoustics and the effect of air absorption. Many sources state that it is only a perceptual factor in big spaces - or over long distances), but I haven't found a simple approximation for calculating a lowpass filter cutoff frequency. Does anyone perhaps have a good approximation or knows a source? I'd be happy with a calculation only based on distance, assuming some default pressure and humidity. Best wishes and TIA, Jeanette -- * Website: http://juliencoder.de - for summer is a state of sound * Youtube: https://www.youtube.com/channel/UCMS4rfGrTwz8W7jhC1Jnv7g * Audiobombs: https://www.audiobombs.com/users/jeanette_c * GitHub: https://github.com/jeanette-c I saw your smile Stay with me a while <3 (Britney Spears) Csound mailing list Csound@listserv.heanet.ie https://listserv.heanet.ie/cgi-bin/wa?A0=CSOUND Send bugs reports to https://github.com/csound/csound/issues Discussions of bugs and features can be posted here

Date	2021-09-12 20:34
From	Partev Sarkissian <0000060b2ef1338e-dmarc-request@LISTSERV.HEANET.IE>
Subject	Re: [Csnd] Simplistic approximation of air absorption (cutoff frequency)
	As I recall speed of sound is 1,130 ft/s, for 25° C, at 14.7 psi at sea level (1966 standard). Don't know helpful that is, but it may be a place to start. https://www.google.com/search?q=air+absorption&ie=utf-8&oe=utf-8&client=firefox-b-1 https://ccrma.stanford.edu/~jos/pasp/Air_Absorption.html >From Julius Smith's book-3 "Physical Audio Signal Processing". https://en.wikipedia.org/wiki/Reynolds_number A bit more esoteric. Used this a lot during my aeronautical engineer study days, to look at laminar to turbulent air flow over a surface (wing and body) of an aircraft. Hope one or more of these helps. -PBS -----Original Message----- From: Jeanette C. <julien@MAIL.UPB.DE> To: CSOUND@LISTSERV.HEANET.IE Sent: Wed, Sep 8, 2021 5:39 pm Subject: [Csnd] Simplistic approximation of air absorption (cutoff frequency) Hey hey, I am looking at acoustics and the effect of air absorption. Many sources state that it is only a perceptual factor in big spaces - or over long distances), but I haven't found a simple approximation for calculating a lowpass filter cutoff frequency. Does anyone perhaps have a good approximation or knows a source? I'd be happy with a calculation only based on distance, assuming some default pressure and humidity. Best wishes and TIA, Jeanette -- * Website: http://juliencoder.de - for summer is a state of sound * Youtube: https://www.youtube.com/channel/UCMS4rfGrTwz8W7jhC1Jnv7g * Audiobombs: https://www.audiobombs.com/users/jeanette_c * GitHub: https://github.com/jeanette-c I saw your smile Stay with me a while <3 (Britney Spears) Csound mailing list Csound@listserv.heanet.ie https://listserv.heanet.ie/cgi-bin/wa?A0=CSOUND Send bugs reports to https://github.com/csound/csound/issues Discussions of bugs and features can be posted here Csound mailing list Csound@listserv.heanet.ie https://listserv.heanet.ie/cgi-bin/wa?A0=CSOUND Send bugs reports to https://github.com/csound/csound/issues Discussions of bugs and features can be posted here

Date	2021-09-12 23:13
From	"Dr. Richard Boulanger"
Subject	Re: [Csnd] Simplistic approximation of air absorption (cutoff frequency)
	Wow PBS, I am smiling from ear to ear as I read your advice and email. The Csound Community never ceases to amaze and inspire me. It is why I am so dedicated to sharing Csound with everyone - I want them to know and meet all of you! Have a great day. And thank you for making mine! - Dr.B Dr. Richard Boulanger Professor Electronic Production and Design Berklee College of Music Professional Writing & Technology Division On Sun, Sep 12, 2021 at 3:34 PM Partev Sarkissian <0000060b2ef1338e-dmarc-request@listserv.heanet.ie> wrote: As I recall speed of sound is 1,130 ft/s, for 25° C, at 14.7 psi at sea level (1966 standard). Don't know helpful that is, but it may be a place to start. https://www.google.com/search?q=air+absorption&ie=utf-8&oe=utf-8&client=firefox-b-1 https://ccrma.stanford.edu/~jos/pasp/Air_Absorption.html >From Julius Smith's book-3 "Physical Audio Signal Processing". https://en.wikipedia.org/wiki/Reynolds_number A bit more esoteric. Used this a lot during my aeronautical engineer study days, to look at laminar to turbulent air flow over a surface (wing and body) of an aircraft. Hope one or more of these helps. -PBS -----Original Message----- From: Jeanette C. <julien@MAIL.UPB.DE> To: CSOUND@LISTSERV.HEANET.IE Sent: Wed, Sep 8, 2021 5:39 pm Subject: [Csnd] Simplistic approximation of air absorption (cutoff frequency) Hey hey, I am looking at acoustics and the effect of air absorption. Many sources state that it is only a perceptual factor in big spaces - or over long distances), but I haven't found a simple approximation for calculating a lowpass filter cutoff frequency. Does anyone perhaps have a good approximation or knows a source? I'd be happy with a calculation only based on distance, assuming some default pressure and humidity. Best wishes and TIA, Jeanette -- * Website: http://juliencoder.de - for summer is a state of sound * Youtube: https://www.youtube.com/channel/UCMS4rfGrTwz8W7jhC1Jnv7g * Audiobombs: https://www.audiobombs.com/users/jeanette_c * GitHub: https://github.com/jeanette-c I saw your smile Stay with me a while <3 (Britney Spears) Csound mailing list Csound@listserv.heanet.ie https://listserv.heanet.ie/cgi-bin/wa?A0=CSOUND Send bugs reports to https://github.com/csound/csound/issues Discussions of bugs and features can be posted here Csound mailing list Csound@listserv.heanet.ie https://listserv.heanet.ie/cgi-bin/wa?A0=CSOUND Send bugs reports to https://github.com/csound/csound/issues Discussions of bugs and features can be posted here Csound mailing list Csound@listserv.heanet.ie https://listserv.heanet.ie/cgi-bin/wa?A0=CSOUND Send bugs reports to https://github.com/csound/csound/issues Discussions of bugs and features can be posted here

Date	2021-09-13 02:36
From	Michael Gogins
Subject	Re: [Csnd] Simplistic approximation of air absorption (cutoff frequency)
	I have used this approximation in my spatialization, borrowed mostly from Jan Jacob Hoffmann. The idea is to filter more of the higher frequencies with greater distance. ; Zero distance blows this up. opcode LowpassByDistance, a, ak asignal, kdistance xin afiltered butterlp asignal, 22000 * sqrt(1.0 / kdistance) + .000001 abalanced balance afiltered, asignal xout abalanced endop Regards, Mike ----------------------------------------------------- Michael Gogins Irreducible Productions http://michaelgogins.tumblr.com Michael dot Gogins at gmail dot com On Sun, Sep 12, 2021 at 6:14 PM Dr. Richard Boulanger <rboulanger@berklee.edu> wrote: Wow PBS, I am smiling from ear to ear as I read your advice and email. The Csound Community never ceases to amaze and inspire me. It is why I am so dedicated to sharing Csound with everyone - I want them to know and meet all of you! Have a great day. And thank you for making mine! - Dr.B Dr. Richard Boulanger Professor Electronic Production and Design Berklee College of Music Professional Writing & Technology Division On Sun, Sep 12, 2021 at 3:34 PM Partev Sarkissian <0000060b2ef1338e-dmarc-request@listserv.heanet.ie> wrote: As I recall speed of sound is 1,130 ft/s, for 25° C, at 14.7 psi at sea level (1966 standard). Don't know helpful that is, but it may be a place to start. https://www.google.com/search?q=air+absorption&ie=utf-8&oe=utf-8&client=firefox-b-1 https://ccrma.stanford.edu/~jos/pasp/Air_Absorption.html >From Julius Smith's book-3 "Physical Audio Signal Processing". https://en.wikipedia.org/wiki/Reynolds_number A bit more esoteric. Used this a lot during my aeronautical engineer study days, to look at laminar to turbulent air flow over a surface (wing and body) of an aircraft. Hope one or more of these helps. -PBS -----Original Message----- From: Jeanette C. <julien@MAIL.UPB.DE> To: CSOUND@LISTSERV.HEANET.IE Sent: Wed, Sep 8, 2021 5:39 pm Subject: [Csnd] Simplistic approximation of air absorption (cutoff frequency) Hey hey, I am looking at acoustics and the effect of air absorption. Many sources state that it is only a perceptual factor in big spaces - or over long distances), but I haven't found a simple approximation for calculating a lowpass filter cutoff frequency. Does anyone perhaps have a good approximation or knows a source? I'd be happy with a calculation only based on distance, assuming some default pressure and humidity. Best wishes and TIA, Jeanette -- * Website: http://juliencoder.de - for summer is a state of sound * Youtube: https://www.youtube.com/channel/UCMS4rfGrTwz8W7jhC1Jnv7g * Audiobombs: https://www.audiobombs.com/users/jeanette_c * GitHub: https://github.com/jeanette-c I saw your smile Stay with me a while <3 (Britney Spears) Csound mailing list Csound@listserv.heanet.ie https://listserv.heanet.ie/cgi-bin/wa?A0=CSOUND Send bugs reports to https://github.com/csound/csound/issues Discussions of bugs and features can be posted here Csound mailing list Csound@listserv.heanet.ie https://listserv.heanet.ie/cgi-bin/wa?A0=CSOUND Send bugs reports to https://github.com/csound/csound/issues Discussions of bugs and features can be posted here Csound mailing list Csound@listserv.heanet.ie https://listserv.heanet.ie/cgi-bin/wa?A0=CSOUND Send bugs reports to https://github.com/csound/csound/issues Discussions of bugs and features can be posted here Csound mailing list Csound@listserv.heanet.ie https://listserv.heanet.ie/cgi-bin/wa?A0=CSOUND Send bugs reports to https://github.com/csound/csound/issues Discussions of bugs and features can be posted here

Date	2021-09-13 13:45
From	"Jeanette C."
Subject	Re: [Csnd] Simplistic approximation of air absorption (cutoff frequency)
	Thanks Partev! I was aware of most of those, especially the Julius Smith book, which I am currently reading with great joy. These materials are very detailed, but they required more DSP knowledge than I have, by assuming that people can write a filter matching a certain transfer function. :( It's still fascinating. Best wishes, Jeanette Sep 12 2021, Partev Sarkissian has written: > > As I recall speed of sound is 1,130 ft/s, for 25° C, at 14.7 psi at > sea level (1966 standard). > > Don't know helpful that is, but it may be a place to start. > > https://www.google.com/search?q=air+absorption&ie=utf-8&oe=utf-8&client=firefox-b-1 > > https://ccrma.stanford.edu/~jos/pasp/Air_Absorption.html > From Julius Smith's book-3 "Physical Audio Signal Processing". > > https://en.wikipedia.org/wiki/Reynolds_number > A bit more esoteric. Used this a lot during my aeronautical engineer study days, > to look at laminar to turbulent air flow over a surface (wing and body) of an aircraft. > > Hope one or more of these helps. > > > -PBS > > > > -----Original Message----- > From: Jeanette C. > To: CSOUND@LISTSERV.HEANET.IE > Sent: Wed, Sep 8, 2021 5:39 pm > Subject: [Csnd] Simplistic approximation of air absorption (cutoff frequency) > > Hey hey, > I am looking at acoustics and the effect of air absorption. Many sources state > that it is only a perceptual factor in big spaces - or over long distances), > but I haven't found a simple approximation for calculating a lowpass filter > cutoff frequency. > > Does anyone perhaps have a good approximation or knows a source? I'd be happy > with a calculation only based on distance, assuming some default pressure and > humidity. > > Best wishes and TIA, > > Jeanette > > -- > * Website: http://juliencoder.de - for summer is a state of sound > * Youtube: https://www.youtube.com/channel/UCMS4rfGrTwz8W7jhC1Jnv7g > * Audiobombs: https://www.audiobombs.com/users/jeanette_c > * GitHub: https://github.com/jeanette-c > > I saw your smile > Stay with me a while <3 > (Britney Spears) > > Csound mailing list > Csound@listserv.heanet.ie > https://listserv.heanet.ie/cgi-bin/wa?A0=CSOUND > Send bugs reports to > https://github.com/csound/csound/issues > Discussions of bugs and features can be posted here > > Csound mailing list > Csound@listserv.heanet.ie > https://listserv.heanet.ie/cgi-bin/wa?A0=CSOUND > Send bugs reports to > https://github.com/csound/csound/issues > Discussions of bugs and features can be posted here > -- * Website: http://juliencoder.de - for summer is a state of sound * Youtube: https://www.youtube.com/channel/UCMS4rfGrTwz8W7jhC1Jnv7g * Audiobombs: https://www.audiobombs.com/users/jeanette_c * GitHub: https://github.com/jeanette-c When you need someone, you just turn around and I will be there <3 (Britney Spears) Csound mailing list Csound@listserv.heanet.ie https://listserv.heanet.ie/cgi-bin/wa?A0=CSOUND Send bugs reports to https://github.com/csound/csound/issues Discussions of bugs and features can be posted here

Date	2021-09-13 13:46
From	"Jeanette C."
Subject	Re: [Csnd] Simplistic approximation of air absorption (cutoff frequency)
	Thanks Michael, this is exactly what I was looking for! This will get me going. Nice UDO. Best wishes, Jeanette Sep 13 2021, Michael Gogins has written: > I have used this approximation in my spatialization, borrowed mostly from > Jan Jacob Hoffmann. The idea is to filter more of the higher frequencies > with greater distance. > > ; Zero distance blows this up. > opcode LowpassByDistance, a, ak > asignal, kdistance xin > afiltered butterlp asignal, 22000 * sqrt(1.0 / kdistance) + .000001 > abalanced balance afiltered, asignal > xout abalanced > endop > > Regards, > Mike > > ----------------------------------------------------- > Michael Gogins > Irreducible Productions > http://michaelgogins.tumblr.com > Michael dot Gogins at gmail dot com > > > On Sun, Sep 12, 2021 at 6:14 PM Dr. Richard Boulanger < > rboulanger@berklee.edu> wrote: > >> Wow PBS, >> >> I am smiling from ear to ear as I read your advice and email. >> The Csound Community never ceases to amaze and inspire me. >> It is why I am so dedicated to sharing Csound with everyone - I want them >> to know and meet all of you! >> >> Have a great day. And thank you for making mine! >> >> - Dr.B >> >> >> Dr. Richard Boulanger >> >> Professor >> >> Electronic Production and Design >> >> Berklee College of Music >> >> Professional Writing & Technology Division >> >> >> On Sun, Sep 12, 2021 at 3:34 PM Partev Sarkissian < >> 0000060b2ef1338e-dmarc-request@listserv.heanet.ie> wrote: >> >>> >>> As I recall speed of sound is 1,130 ft/s, for 25° C, at 14.7 psi at >>> sea level (1966 standard). >>> >>> Don't know helpful that is, but it may be a place to start. >>> >>> >>> https://www.google.com/search?q=air+absorption&ie=utf-8&oe=utf-8&client=firefox-b-1 >>> >>> >>> https://ccrma.stanford.edu/~jos/pasp/Air_Absorption.html >>> From Julius Smith's book-3 "Physical Audio Signal Processing". >>> >>> https://en.wikipedia.org/wiki/Reynolds_number >>> A bit more esoteric. Used this a lot during my aeronautical engineer >>> study days, >>> to look at laminar to turbulent air flow over a surface (wing and body) >>> of an aircraft. >>> >>> Hope one or more of these helps. >>> >>> >>> -PBS >>> >>> >>> >>> -----Original Message----- >>> From: Jeanette C. >>> To: CSOUND@LISTSERV.HEANET.IE >>> Sent: Wed, Sep 8, 2021 5:39 pm >>> Subject: [Csnd] Simplistic approximation of air absorption (cutoff >>> frequency) >>> >>> Hey hey, >>> I am looking at acoustics and the effect of air absorption. Many sources >>> state >>> that it is only a perceptual factor in big spaces - or over long >>> distances), >>> but I haven't found a simple approximation for calculating a lowpass >>> filter >>> cutoff frequency. >>> >>> Does anyone perhaps have a good approximation or knows a source? I'd be >>> happy >>> with a calculation only based on distance, assuming some default pressure >>> and >>> humidity. >>> >>> Best wishes and TIA, >>> >>> Jeanette >>> >>> -- >>> * Website: http://juliencoder.de >>> - >>> for summer is a state of sound >>> * Youtube: https://www.youtube.com/channel/UCMS4rfGrTwz8W7jhC1Jnv7g >>> >>> * Audiobombs: https://www.audiobombs.com/users/jeanette_c >>> >>> * GitHub: https://github.com/jeanette-c >>> >>> >>> I saw your smile >>> Stay with me a while <3 >>> (Britney Spears) >>> >>> Csound mailing list >>> Csound@listserv.heanet.ie >>> https://listserv.heanet.ie/cgi-bin/wa?A0=CSOUND >>> >>> Send bugs reports to >>> https://github.com/csound/csound/issues >>> >>> Discussions of bugs and features can be posted here >>> Csound mailing list Csound@listserv.heanet.ie >>> https://listserv.heanet.ie/cgi-bin/wa?A0=CSOUND >>> >>> Send bugs reports to https://github.com/csound/csound/issues >>> >>> Discussions of bugs and features can be posted here >> >> Csound mailing list Csound@listserv.heanet.ie >> https://listserv.heanet.ie/cgi-bin/wa?A0=CSOUND Send bugs reports to >> https://github.com/csound/csound/issues Discussions of bugs and features >> can be posted here > > Csound mailing list > Csound@listserv.heanet.ie > https://listserv.heanet.ie/cgi-bin/wa?A0=CSOUND > Send bugs reports to > https://github.com/csound/csound/issues > Discussions of bugs and features can be posted here > -- * Website: http://juliencoder.de - for summer is a state of sound * Youtube: https://www.youtube.com/channel/UCMS4rfGrTwz8W7jhC1Jnv7g * Audiobombs: https://www.audiobombs.com/users/jeanette_c * GitHub: https://github.com/jeanette-c When you need someone, you just turn around and I will be there <3 (Britney Spears) Csound mailing list Csound@listserv.heanet.ie https://listserv.heanet.ie/cgi-bin/wa?A0=CSOUND Send bugs reports to https://github.com/csound/csound/issues Discussions of bugs and features can be posted here

Date	2021-09-13 19:45
From	Partev Sarkissian <0000060b2ef1338e-dmarc-request@LISTSERV.HEANET.IE>
Subject	Re: [Csnd] Simplistic approximation of air absorption (cutoff frequency)
	Anytime. Been a while since we last crossed paths at NAMM in Anaheim at Big Fish Synth booth I think. Always like it when they have that Mellotron open. And there's always my FB and web page. Already met Oyvend at AES LA, 2016 I think. We have a mutual friend and colleague at C4DM, Josh Reiss. Makes my day that I made your day. Thanks. Til the next NAMM. Cheers, -Partev -----Original Message----- From: Dr. Richard Boulanger <rboulanger@BERKLEE.EDU> To: CSOUND@LISTSERV.HEANET.IE Sent: Sun, Sep 12, 2021 3:13 pm Subject: Re: [Csnd] Simplistic approximation of air absorption (cutoff frequency) Wow PBS, I am smiling from ear to ear as I read your advice and email. The Csound Community never ceases to amaze and inspire me. It is why I am so dedicated to sharing Csound with everyone - I want them to know and meet all of you! Have a great day. And thank you for making mine! - Dr.B Dr. Richard Boulanger Professor Electronic Production and Design Berklee College of Music Professional Writing & Technology Division On Sun, Sep 12, 2021 at 3:34 PM Partev Sarkissian <0000060b2ef1338e-dmarc-request@listserv.heanet.ie> wrote: As I recall speed of sound is 1,130 ft/s, for 25° C, at 14.7 psi at sea level (1966 standard). Don't know how helpful that is, but it may be a place to start. https://www.google.com/search?q=air+absorption&ie=utf-8&oe=utf-8&client=firefox-b-1 https://ccrma.stanford.edu/~jos/pasp/Air_Absorption.html >From Julius Smith's book-3 "Physical Audio Signal Processing". https://en.wikipedia.org/wiki/Reynolds_number A bit more esoteric. Used this a lot during my aeronautical engineer study days, to look at laminar to turbulent air flow over a surface (wing and body) of an aircraft. Hope one or more of these helps. -PBS -----Original Message----- From: Jeanette C. <julien@MAIL.UPB.DE> To: CSOUND@LISTSERV.HEANET.IE Sent: Wed, Sep 8, 2021 5:39 pm Subject: [Csnd] Simplistic approximation of air absorption (cutoff frequency) Hey hey, I am looking at acoustics and the effect of air absorption. Many sources state that it is only a perceptual factor in big spaces - or over long distances), but I haven't found a simple approximation for calculating a lowpass filter cutoff frequency. Does anyone perhaps have a good approximation or knows a source? I'd be happy with a calculation only based on distance, assuming some default pressure and humidity. Best wishes and TIA, Jeanette -- * Website: http://juliencoder.de - for summer is a state of sound * Youtube: https://www.youtube.com/channel/UCMS4rfGrTwz8W7jhC1Jnv7g * Audiobombs: https://www.audiobombs.com/users/jeanette_c * GitHub: https://github.com/jeanette-c I saw your smile Stay with me a while <3 (Britney Spears) Csound mailing list Csound@listserv.heanet.ie https://listserv.heanet.ie/cgi-bin/wa?A0=CSOUND Send bugs reports to https://github.com/csound/csound/issues Discussions of bugs and features can be posted here Csound mailing list Csound@listserv.heanet.ie https://listserv.heanet.ie/cgi-bin/wa?A0=CSOUND Send bugs reports to https://github.com/csound/csound/issues Discussions of bugs and features can be posted here Csound mailing list Csound@listserv.heanet.ie https://listserv.heanet.ie/cgi-bin/wa?A0=CSOUND Send bugs reports to https://github.com/csound/csound/issues Discussions of bugs and features can be posted here Csound mailing list Csound@listserv.heanet.ie https://listserv.heanet.ie/cgi-bin/wa?A0=CSOUND Send bugs reports to https://github.com/csound/csound/issues Discussions of bugs and features can be posted here

Date	2021-09-13 19:57
From	Partev Sarkissian <0000060b2ef1338e-dmarc-request@LISTSERV.HEANET.IE>
Subject	Re: [Csnd] Simplistic approximation of air absorption (cutoff frequency)
	Modeling has come a long way since the 1970's from back when it was called 'numerical modeling', used for stick figure simulations, in a 8-bit CPU world. Too slow for the DSP of today with Ghz clocks and 64+ bit math processing. Math translation is easier too, so math modeling is more straight forward. Some of it is a bit new to me too. Can't get enough of it. -PBS -----Original Message----- From: Jeanette C. <julien@MAIL.UPB.DE> To: CSOUND@LISTSERV.HEANET.IE Sent: Mon, Sep 13, 2021 5:45 am Subject: Re: [Csnd] Simplistic approximation of air absorption (cutoff frequency) Thanks Partev! I was aware of most of those, especially the Julius Smith book, which I am currently reading with great joy. These materials are very detailed, but they required more DSP knowledge than I have, by assuming that people can write a filter matching a certain transfer function. :( It's still fascinating. Best wishes, Jeanette Sep 12 2021, Partev Sarkissian has written: > > As I recall speed of sound is 1,130 ft/s, for 25° C, at 14.7 psi at > sea level (1966 standard). > > Don't know helpful that is, but it may be a place to start. > > https://www.google.com/search?q=air+absorption&ie=utf-8&oe=utf-8&client=firefox-b-1 > > https://ccrma.stanford.edu/~jos/pasp/Air_Absorption.html > From Julius Smith's book-3 "Physical Audio Signal Processing". > > https://en.wikipedia.org/wiki/Reynolds_number > A bit more esoteric. Used this a lot during my aeronautical engineer study days, > to look at laminar to turbulent air flow over a surface (wing and body) of an aircraft. > > Hope one or more of these helps. > > > -PBS > > > > -----Original Message----- > From: Jeanette C. <julien@MAIL.UPB.DE> > To: CSOUND@LISTSERV.HEANET.IE > Sent: Wed, Sep 8, 2021 5:39 pm > Subject: [Csnd] Simplistic approximation of air absorption (cutoff frequency) > > Hey hey, > I am looking at acoustics and the effect of air absorption. Many sources state > that it is only a perceptual factor in big spaces - or over long distances), > but I haven't found a simple approximation for calculating a lowpass filter > cutoff frequency. > > Does anyone perhaps have a good approximation or knows a source? I'd be happy > with a calculation only based on distance, assuming some default pressure and > humidity. > > Best wishes and TIA, > > Jeanette > > -- > * Website: http://juliencoder.de - for summer is a state of sound > * Youtube: https://www.youtube.com/channel/UCMS4rfGrTwz8W7jhC1Jnv7g > * Audiobombs: https://www.audiobombs.com/users/jeanette_c > * GitHub: https://github.com/jeanette-c > > I saw your smile > Stay with me a while <3 > (Britney Spears) > > Csound mailing list > Csound@listserv.heanet.ie > https://listserv.heanet.ie/cgi-bin/wa?A0=CSOUND > Send bugs reports to > https://github.com/csound/csound/issues > Discussions of bugs and features can be posted here > > Csound mailing list > Csound@listserv.heanet.ie > https://listserv.heanet.ie/cgi-bin/wa?A0=CSOUND > Send bugs reports to > https://github.com/csound/csound/issues > Discussions of bugs and features can be posted here > -- * Website: http://juliencoder.de - for summer is a state of sound * Youtube: https://www.youtube.com/channel/UCMS4rfGrTwz8W7jhC1Jnv7g * Audiobombs: https://www.audiobombs.com/users/jeanette_c * GitHub: https://github.com/jeanette-c When you need someone, you just turn around and I will be there <3 (Britney Spears) Csound mailing list Csound@listserv.heanet.ie https://listserv.heanet.ie/cgi-bin/wa?A0=CSOUND Send bugs reports to https://github.com/csound/csound/issues Discussions of bugs and features can be posted here Csound mailing list Csound@listserv.heanet.ie https://listserv.heanet.ie/cgi-bin/wa?A0=CSOUND Send bugs reports to https://github.com/csound/csound/issues Discussions of bugs and features can be posted here

Date	2021-09-13 20:00
From	Partev Sarkissian <0000060b2ef1338e-dmarc-request@LISTSERV.HEANET.IE>
Subject	Re: [Csnd] Simplistic approximation of air absorption (cutoff frequency)
	Very nice. dB drops off by inverse square of the the radial distance from the source? -PBS -----Original Message----- From: Jeanette C. <julien@MAIL.UPB.DE> To: CSOUND@LISTSERV.HEANET.IE Sent: Mon, Sep 13, 2021 5:46 am Subject: Re: [Csnd] Simplistic approximation of air absorption (cutoff frequency) Thanks Michael, this is exactly what I was looking for! This will get me going. Nice UDO. Best wishes, Jeanette Sep 13 2021, Michael Gogins has written: > I have used this approximation in my spatialization, borrowed mostly from > Jan Jacob Hoffmann. The idea is to filter more of the higher frequencies > with greater distance. > > ; Zero distance blows this up. > opcode LowpassByDistance, a, ak > asignal, kdistance xin > afiltered butterlp asignal, 22000 * sqrt(1.0 / kdistance) + .000001 > abalanced balance afiltered, asignal > xout abalanced > endop > > Regards, > Mike > > ----------------------------------------------------- > Michael Gogins > Irreducible Productions > http://michaelgogins.tumblr.com > Michael dot Gogins at gmail dot com > > > On Sun, Sep 12, 2021 at 6:14 PM Dr. Richard Boulanger < > rboulanger@berklee.edu> wrote: > >> Wow PBS, >> >> I am smiling from ear to ear as I read your advice and email. >> The Csound Community never ceases to amaze and inspire me. >> It is why I am so dedicated to sharing Csound with everyone - I want them >> to know and meet all of you! >> >> Have a great day. And thank you for making mine! >> >> - Dr.B >> >> >> Dr. Richard Boulanger >> >> Professor >> >> Electronic Production and Design >> >> Berklee College of Music >> >> Professional Writing & Technology Division >> >> >> On Sun, Sep 12, 2021 at 3:34 PM Partev Sarkissian < >> 0000060b2ef1338e-dmarc-request@listserv.heanet.ie> wrote: >> >>> >>> As I recall speed of sound is 1,130 ft/s, for 25° C, at 14.7 psi at >>> sea level (1966 standard). >>> >>> Don't know helpful that is, but it may be a place to start. >>> >>> >>> https://www.google.com/search?q=air+absorption&ie=utf-8&oe=utf-8&client=firefox-b-1 >>> >>> >>> https://ccrma.stanford.edu/~jos/pasp/Air_Absorption.html >>> From Julius Smith's book-3 "Physical Audio Signal Processing". >>> >>> https://en.wikipedia.org/wiki/Reynolds_number >>> A bit more esoteric. Used this a lot during my aeronautical engineer >>> study days, >>> to look at laminar to turbulent air flow over a surface (wing and body) >>> of an aircraft. >>> >>> Hope one or more of these helps. >>> >>> >>> -PBS >>> >>> >>> >>> -----Original Message----- >>> From: Jeanette C. <julien@MAIL.UPB.DE> >>> To: CSOUND@LISTSERV.HEANET.IE >>> Sent: Wed, Sep 8, 2021 5:39 pm >>> Subject: [Csnd] Simplistic approximation of air absorption (cutoff >>> frequency) >>> >>> Hey hey, >>> I am looking at acoustics and the effect of air absorption. Many sources >>> state >>> that it is only a perceptual factor in big spaces - or over long >>> distances), >>> but I haven't found a simple approximation for calculating a lowpass >>> filter >>> cutoff frequency. >>> >>> Does anyone perhaps have a good approximation or knows a source? I'd be >>> happy >>> with a calculation only based on distance, assuming some default pressure >>> and >>> humidity. >>> >>> Best wishes and TIA, >>> >>> Jeanette >>> >>> -- >>> * Website: http://juliencoder.de >>> <https://us-west-2.protection.sophos.com?d=juliencoder.de&u=aHR0cDovL2p1bGllbmNvZGVyLmRlLw==&i=NWYxNzBkMDNiNTVmZGEwZmIyNjczYmRm&t=S1czNHhhZE5yRWVaVVI0Vk9tYUJHRkdPZEhnOWVmTDdSc1VqTDltRVFOND0=&h=03c9bbdd5a65430ebca772df08d7f2b1>- >>> for summer is a state of sound >>> * Youtube: https://www.youtube.com/channel/UCMS4rfGrTwz8W7jhC1Jnv7g >>> <https://us-west-2.protection.sophos.com?d=youtube.com&u=aHR0cHM6Ly93d3cueW91dHViZS5jb20vY2hhbm5lbC9VQ01TNHJmR3JUd3o4VzdqaEMxSm52N2c=&i=NWYxNzBkMDNiNTVmZGEwZmIyNjczYmRm&t=TXRCZnZOZEtNRDYvN0R0QXpMUHh0ZVMzNU9HOTJFNnU5Nkk4aFNEa2NuST0=&h=03c9bbdd5a65430ebca772df08d7f2b1> >>> * Audiobombs: https://www.audiobombs.com/users/jeanette_c >>> <https://us-west-2.protection.sophos.com?d=audiobombs.com&u=aHR0cHM6Ly93d3cuYXVkaW9ib21icy5jb20vdXNlcnMvamVhbmV0dGVfYw==&i=NWYxNzBkMDNiNTVmZGEwZmIyNjczYmRm&t=emFIeXVKRkJiOGJ2c1BXVkJEc1hJVGdVUisxZ25OSU5zQXJ0dEQ5SnlXST0=&h=03c9bbdd5a65430ebca772df08d7f2b1> >>> * GitHub: https://github.com/jeanette-c >>> <https://us-west-2.protection.sophos.com?d=github.com&u=aHR0cHM6Ly9naXRodWIuY29tL2plYW5ldHRlLWM=&i=NWYxNzBkMDNiNTVmZGEwZmIyNjczYmRm&t=anhzMlhqbG9WcGEzdTRSdE1pYkdHb2lOSmFGUW9wYkZBMmJONXRaWGpyMD0=&h=03c9bbdd5a65430ebca772df08d7f2b1> >>> >>> I saw your smile >>> Stay with me a while <3 >>> (Britney Spears) >>> >>> Csound mailing list >>> Csound@listserv.heanet.ie >>> https://listserv.heanet.ie/cgi-bin/wa?A0=CSOUND >>> <https://us-west-2.protection.sophos.com?d=heanet.ie&u=aHR0cHM6Ly9saXN0c2Vydi5oZWFuZXQuaWUvY2dpLWJpbi93YT9BMD1DU09VTkQ=&i=NWYxNzBkMDNiNTVmZGEwZmIyNjczYmRm&t=WVZMRlI4dlFUVUZ6V2NTOUU5eE9lZnFIemtoc2hxYlBDMFFCWmtKZzhzRT0=&h=03c9bbdd5a65430ebca772df08d7f2b1> >>> Send bugs reports to >>> https://github.com/csound/csound/issues >>> <https://us-west-2.protection.sophos.com?d=github.com&u=aHR0cHM6Ly9naXRodWIuY29tL2Nzb3VuZC9jc291bmQvaXNzdWVz&i=NWYxNzBkMDNiNTVmZGEwZmIyNjczYmRm&t=YlNrQ2lLclRLZUpGUE1iR0FyY2M1eW1NTUU5SUozWlJwMTNZU2NXT1BLOD0=&h=03c9bbdd5a65430ebca772df08d7f2b1> >>> Discussions of bugs and features can be posted here >>> Csound mailing list Csound@listserv.heanet.ie >>> https://listserv.heanet.ie/cgi-bin/wa?A0=CSOUND >>> <https://us-west-2.protection.sophos.com?d=heanet.ie&u=aHR0cHM6Ly9saXN0c2Vydi5oZWFuZXQuaWUvY2dpLWJpbi93YT9BMD1DU09VTkQ=&i=NWYxNzBkMDNiNTVmZGEwZmIyNjczYmRm&t=WVZMRlI4dlFUVUZ6V2NTOUU5eE9lZnFIemtoc2hxYlBDMFFCWmtKZzhzRT0=&h=03c9bbdd5a65430ebca772df08d7f2b1> >>> Send bugs reports to https://github.com/csound/csound/issues >>> <https://us-west-2.protection.sophos.com?d=github.com&u=aHR0cHM6Ly9naXRodWIuY29tL2Nzb3VuZC9jc291bmQvaXNzdWVz&i=NWYxNzBkMDNiNTVmZGEwZmIyNjczYmRm&t=YlNrQ2lLclRLZUpGUE1iR0FyY2M1eW1NTUU5SUozWlJwMTNZU2NXT1BLOD0=&h=03c9bbdd5a65430ebca772df08d7f2b1> >>> Discussions of bugs and features can be posted here >> >> Csound mailing list Csound@listserv.heanet.ie >> https://listserv.heanet.ie/cgi-bin/wa?A0=CSOUND Send bugs reports to >> https://github.com/csound/csound/issues Discussions of bugs and features >> can be posted here > > Csound mailing list > Csound@listserv.heanet.ie > https://listserv.heanet.ie/cgi-bin/wa?A0=CSOUND > Send bugs reports to > https://github.com/csound/csound/issues > Discussions of bugs and features can be posted here > -- * Website: http://juliencoder.de - for summer is a state of sound * Youtube: https://www.youtube.com/channel/UCMS4rfGrTwz8W7jhC1Jnv7g * Audiobombs: https://www.audiobombs.com/users/jeanette_c * GitHub: https://github.com/jeanette-c When you need someone, you just turn around and I will be there <3 (Britney Spears) Csound mailing list Csound@listserv.heanet.ie https://listserv.heanet.ie/cgi-bin/wa?A0=CSOUND Send bugs reports to https://github.com/csound/csound/issues Discussions of bugs and features can be posted here Csound mailing list Csound@listserv.heanet.ie https://listserv.heanet.ie/cgi-bin/wa?A0=CSOUND Send bugs reports to https://github.com/csound/csound/issues Discussions of bugs and features can be posted here

Date	2021-09-13 21:53
From	Michael Gogins
Subject	Re: [Csnd] Simplistic approximation of air absorption (cutoff frequency)
	No, this part drops the highpass cutoff frequency by the inverse square of the radial distance from the source. Best, Mike ----------------------------------------------------- Michael Gogins Irreducible Productions http://michaelgogins.tumblr.com Michael dot Gogins at gmail dot com On Mon, Sep 13, 2021 at 3:01 PM Partev Sarkissian <0000060b2ef1338e-dmarc-request@listserv.heanet.ie> wrote: Very nice. dB drops off by inverse square of the the radial distance from the source? -PBS -----Original Message----- From: Jeanette C. <julien@MAIL.UPB.DE> To: CSOUND@LISTSERV.HEANET.IE Sent: Mon, Sep 13, 2021 5:46 am Subject: Re: [Csnd] Simplistic approximation of air absorption (cutoff frequency) Thanks Michael, this is exactly what I was looking for! This will get me going. Nice UDO. Best wishes, Jeanette Sep 13 2021, Michael Gogins has written: > I have used this approximation in my spatialization, borrowed mostly from > Jan Jacob Hoffmann. The idea is to filter more of the higher frequencies > with greater distance. > > ; Zero distance blows this up. > opcode LowpassByDistance, a, ak > asignal, kdistance xin > afiltered butterlp asignal, 22000 * sqrt(1.0 / kdistance) + .000001 > abalanced balance afiltered, asignal > xout abalanced > endop > > Regards, > Mike > > ----------------------------------------------------- > Michael Gogins > Irreducible Productions > http://michaelgogins.tumblr.com > Michael dot Gogins at gmail dot com > > > On Sun, Sep 12, 2021 at 6:14 PM Dr. Richard Boulanger < > rboulanger@berklee.edu> wrote: > >> Wow PBS, >> >> I am smiling from ear to ear as I read your advice and email. >> The Csound Community never ceases to amaze and inspire me. >> It is why I am so dedicated to sharing Csound with everyone - I want them >> to know and meet all of you! >> >> Have a great day. And thank you for making mine! >> >> - Dr.B >> >> >> Dr. Richard Boulanger >> >> Professor >> >> Electronic Production and Design >> >> Berklee College of Music >> >> Professional Writing & Technology Division >> >> >> On Sun, Sep 12, 2021 at 3:34 PM Partev Sarkissian < >> 0000060b2ef1338e-dmarc-request@listserv.heanet.ie> wrote: >> >>> >>> As I recall speed of sound is 1,130 ft/s, for 25° C, at 14.7 psi at >>> sea level (1966 standard). >>> >>> Don't know helpful that is, but it may be a place to start. >>> >>> >>> https://www.google.com/search?q=air+absorption&ie=utf-8&oe=utf-8&client=firefox-b-1 >>> >>> >>> https://ccrma.stanford.edu/~jos/pasp/Air_Absorption.html >>> From Julius Smith's book-3 "Physical Audio Signal Processing". >>> >>> https://en.wikipedia.org/wiki/Reynolds_number >>> A bit more esoteric. Used this a lot during my aeronautical engineer >>> study days, >>> to look at laminar to turbulent air flow over a surface (wing and body) >>> of an aircraft. >>> >>> Hope one or more of these helps. >>> >>> >>> -PBS >>> >>> >>> >>> -----Original Message----- >>> From: Jeanette C. <julien@MAIL.UPB.DE> >>> To: CSOUND@LISTSERV.HEANET.IE >>> Sent: Wed, Sep 8, 2021 5:39 pm >>> Subject: [Csnd] Simplistic approximation of air absorption (cutoff >>> frequency) >>> >>> Hey hey, >>> I am looking at acoustics and the effect of air absorption. Many sources >>> state >>> that it is only a perceptual factor in big spaces - or over long >>> distances), >>> but I haven't found a simple approximation for calculating a lowpass >>> filter >>> cutoff frequency. >>> >>> Does anyone perhaps have a good approximation or knows a source? I'd be >>> happy >>> with a calculation only based on distance, assuming some default pressure >>> and >>> humidity. >>> >>> Best wishes and TIA, >>> >>> Jeanette >>> >>> -- >>> * Website: http://juliencoder.de >>> <https://us-west-2.protection.sophos.com?d=juliencoder.de&u=aHR0cDovL2p1bGllbmNvZGVyLmRlLw==&i=NWYxNzBkMDNiNTVmZGEwZmIyNjczYmRm&t=S1czNHhhZE5yRWVaVVI0Vk9tYUJHRkdPZEhnOWVmTDdSc1VqTDltRVFOND0=&h=03c9bbdd5a65430ebca772df08d7f2b1>- >>> for summer is a state of sound >>> * Youtube: https://www.youtube.com/channel/UCMS4rfGrTwz8W7jhC1Jnv7g >>> <https://us-west-2.protection.sophos.com?d=youtube.com&u=aHR0cHM6Ly93d3cueW91dHViZS5jb20vY2hhbm5lbC9VQ01TNHJmR3JUd3o4VzdqaEMxSm52N2c=&i=NWYxNzBkMDNiNTVmZGEwZmIyNjczYmRm&t=TXRCZnZOZEtNRDYvN0R0QXpMUHh0ZVMzNU9HOTJFNnU5Nkk4aFNEa2NuST0=&h=03c9bbdd5a65430ebca772df08d7f2b1> >>> * Audiobombs: https://www.audiobombs.com/users/jeanette_c >>> <https://us-west-2.protection.sophos.com?d=audiobombs.com&u=aHR0cHM6Ly93d3cuYXVkaW9ib21icy5jb20vdXNlcnMvamVhbmV0dGVfYw==&i=NWYxNzBkMDNiNTVmZGEwZmIyNjczYmRm&t=emFIeXVKRkJiOGJ2c1BXVkJEc1hJVGdVUisxZ25OSU5zQXJ0dEQ5SnlXST0=&h=03c9bbdd5a65430ebca772df08d7f2b1> >>> * GitHub: https://github.com/jeanette-c >>> <https://us-west-2.protection.sophos.com?d=github.com&u=aHR0cHM6Ly9naXRodWIuY29tL2plYW5ldHRlLWM=&i=NWYxNzBkMDNiNTVmZGEwZmIyNjczYmRm&t=anhzMlhqbG9WcGEzdTRSdE1pYkdHb2lOSmFGUW9wYkZBMmJONXRaWGpyMD0=&h=03c9bbdd5a65430ebca772df08d7f2b1> >>> >>> I saw your smile >>> Stay with me a while <3 >>> (Britney Spears) >>> >>> Csound mailing list >>> Csound@listserv.heanet.ie >>> https://listserv.heanet.ie/cgi-bin/wa?A0=CSOUND >>> <https://us-west-2.protection.sophos.com?d=heanet.ie&u=aHR0cHM6Ly9saXN0c2Vydi5oZWFuZXQuaWUvY2dpLWJpbi93YT9BMD1DU09VTkQ=&i=NWYxNzBkMDNiNTVmZGEwZmIyNjczYmRm&t=WVZMRlI4dlFUVUZ6V2NTOUU5eE9lZnFIemtoc2hxYlBDMFFCWmtKZzhzRT0=&h=03c9bbdd5a65430ebca772df08d7f2b1> >>> Send bugs reports to >>> https://github.com/csound/csound/issues >>> <https://us-west-2.protection.sophos.com?d=github.com&u=aHR0cHM6Ly9naXRodWIuY29tL2Nzb3VuZC9jc291bmQvaXNzdWVz&i=NWYxNzBkMDNiNTVmZGEwZmIyNjczYmRm&t=YlNrQ2lLclRLZUpGUE1iR0FyY2M1eW1NTUU5SUozWlJwMTNZU2NXT1BLOD0=&h=03c9bbdd5a65430ebca772df08d7f2b1> >>> Discussions of bugs and features can be posted here >>> Csound mailing list Csound@listserv.heanet.ie >>> https://listserv.heanet.ie/cgi-bin/wa?A0=CSOUND >>> <https://us-west-2.protection.sophos.com?d=heanet.ie&u=aHR0cHM6Ly9saXN0c2Vydi5oZWFuZXQuaWUvY2dpLWJpbi93YT9BMD1DU09VTkQ=&i=NWYxNzBkMDNiNTVmZGEwZmIyNjczYmRm&t=WVZMRlI4dlFUVUZ6V2NTOUU5eE9lZnFIemtoc2hxYlBDMFFCWmtKZzhzRT0=&h=03c9bbdd5a65430ebca772df08d7f2b1> >>> Send bugs reports to https://github.com/csound/csound/issues >>> <https://us-west-2.protection.sophos.com?d=github.com&u=aHR0cHM6Ly9naXRodWIuY29tL2Nzb3VuZC9jc291bmQvaXNzdWVz&i=NWYxNzBkMDNiNTVmZGEwZmIyNjczYmRm&t=YlNrQ2lLclRLZUpGUE1iR0FyY2M1eW1NTUU5SUozWlJwMTNZU2NXT1BLOD0=&h=03c9bbdd5a65430ebca772df08d7f2b1> >>> Discussions of bugs and features can be posted here >> >> Csound mailing list Csound@listserv.heanet.ie >> https://listserv.heanet.ie/cgi-bin/wa?A0=CSOUND Send bugs reports to >> https://github.com/csound/csound/issues Discussions of bugs and features >> can be posted here > > Csound mailing list > Csound@listserv.heanet.ie > https://listserv.heanet.ie/cgi-bin/wa?A0=CSOUND > Send bugs reports to > https://github.com/csound/csound/issues > Discussions of bugs and features can be posted here > -- * Website: http://juliencoder.de - for summer is a state of sound * Youtube: https://www.youtube.com/channel/UCMS4rfGrTwz8W7jhC1Jnv7g * Audiobombs: https://www.audiobombs.com/users/jeanette_c * GitHub: https://github.com/jeanette-c When you need someone, you just turn around and I will be there <3 (Britney Spears) Csound mailing list Csound@listserv.heanet.ie https://listserv.heanet.ie/cgi-bin/wa?A0=CSOUND Send bugs reports to https://github.com/csound/csound/issues Discussions of bugs and features can be posted here Csound mailing list Csound@listserv.heanet.ie https://listserv.heanet.ie/cgi-bin/wa?A0=CSOUND Send bugs reports to https://github.com/csound/csound/issues Discussions of bugs and features can be posted here Csound mailing list Csound@listserv.heanet.ie https://listserv.heanet.ie/cgi-bin/wa?A0=CSOUND Send bugs reports to https://github.com/csound/csound/issues Discussions of bugs and features can be posted here

Date	2021-09-13 22:01
From	Partev Sarkissian <0000060b2ef1338e-dmarc-request@LISTSERV.HEANET.IE>
Subject	Re: [Csnd] Simplistic approximation of air absorption (cutoff frequency)
	And leaving with a more real world low pass response. Butterworth curve, nice. -PBS -----Original Message----- From: Michael Gogins <michael.gogins@GMAIL.COM> To: CSOUND@LISTSERV.HEANET.IE Sent: Mon, Sep 13, 2021 1:53 pm Subject: Re: [Csnd] Simplistic approximation of air absorption (cutoff frequency) No, this part drops the highpass cutoff frequency by the inverse square of the radial distance from the source. Best, Mike ----------------------------------------------------- Michael Gogins Irreducible Productions http://michaelgogins.tumblr.com Michael dot Gogins at gmail dot com On Mon, Sep 13, 2021 at 3:01 PM Partev Sarkissian <0000060b2ef1338e-dmarc-request@listserv.heanet.ie> wrote: Very nice. dB drops off by inverse square of the the radial distance from the source? -PBS -----Original Message----- From: Jeanette C. <julien@MAIL.UPB.DE> To: CSOUND@LISTSERV.HEANET.IE Sent: Mon, Sep 13, 2021 5:46 am Subject: Re: [Csnd] Simplistic approximation of air absorption (cutoff frequency) Thanks Michael, this is exactly what I was looking for! This will get me going. Nice UDO. Best wishes, Jeanette Sep 13 2021, Michael Gogins has written: > I have used this approximation in my spatialization, borrowed mostly from > Jan Jacob Hoffmann. The idea is to filter more of the higher frequencies > with greater distance. > > ; Zero distance blows this up. > opcode LowpassByDistance, a, ak > asignal, kdistance xin > afiltered butterlp asignal, 22000 * sqrt(1.0 / kdistance) + .000001 > abalanced balance afiltered, asignal > xout abalanced > endop > > Regards, > Mike > > ----------------------------------------------------- > Michael Gogins > Irreducible Productions > http://michaelgogins.tumblr.com > Michael dot Gogins at gmail dot com > > > On Sun, Sep 12, 2021 at 6:14 PM Dr. Richard Boulanger < > rboulanger@berklee.edu> wrote: > >> Wow PBS, >> >> I am smiling from ear to ear as I read your advice and email. >> The Csound Community never ceases to amaze and inspire me. >> It is why I am so dedicated to sharing Csound with everyone - I want them >> to know and meet all of you! >> >> Have a great day. And thank you for making mine! >> >> - Dr.B >> >> >> Dr. Richard Boulanger >> >> Professor >> >> Electronic Production and Design >> >> Berklee College of Music >> >> Professional Writing & Technology Division >> >> >> On Sun, Sep 12, 2021 at 3:34 PM Partev Sarkissian < >> 0000060b2ef1338e-dmarc-request@listserv.heanet.ie> wrote: >> >>> >>> As I recall speed of sound is 1,130 ft/s, for 25° C, at 14.7 psi at >>> sea level (1966 standard). >>> >>> Don't know helpful that is, but it may be a place to start. >>> >>> >>> https://www.google.com/search?q=air+absorption&ie=utf-8&oe=utf-8&client=firefox-b-1 >>> >>> >>> https://ccrma.stanford.edu/~jos/pasp/Air_Absorption.html >>> From Julius Smith's book-3 "Physical Audio Signal Processing". >>> >>> https://en.wikipedia.org/wiki/Reynolds_number >>> A bit more esoteric. Used this a lot during my aeronautical engineer >>> study days, >>> to look at laminar to turbulent air flow over a surface (wing and body) >>> of an aircraft. >>> >>> Hope one or more of these helps. >>> >>> >>> -PBS >>> >>> >>> >>> -----Original Message----- >>> From: Jeanette C. <julien@MAIL.UPB.DE> >>> To: CSOUND@LISTSERV.HEANET.IE >>> Sent: Wed, Sep 8, 2021 5:39 pm >>> Subject: [Csnd] Simplistic approximation of air absorption (cutoff >>> frequency) >>> >>> Hey hey, >>> I am looking at acoustics and the effect of air absorption. Many sources >>> state >>> that it is only a perceptual factor in big spaces - or over long >>> distances), >>> but I haven't found a simple approximation for calculating a lowpass >>> filter >>> cutoff frequency. >>> >>> Does anyone perhaps have a good approximation or knows a source? I'd be >>> happy >>> with a calculation only based on distance, assuming some default pressure >>> and >>> humidity. >>> >>> Best wishes and TIA, >>> >>> Jeanette >>> >>> -- >>> * Website: http://juliencoder.de >>> <https://us-west-2.protection.sophos.com?d=juliencoder.de&u=aHR0cDovL2p1bGllbmNvZGVyLmRlLw==&i=NWYxNzBkMDNiNTVmZGEwZmIyNjczYmRm&t=S1czNHhhZE5yRWVaVVI0Vk9tYUJHRkdPZEhnOWVmTDdSc1VqTDltRVFOND0=&h=03c9bbdd5a65430ebca772df08d7f2b1>- >>> for summer is a state of sound >>> * Youtube: https://www.youtube.com/channel/UCMS4rfGrTwz8W7jhC1Jnv7g >>> <https://us-west-2.protection.sophos.com?d=youtube.com&u=aHR0cHM6Ly93d3cueW91dHViZS5jb20vY2hhbm5lbC9VQ01TNHJmR3JUd3o4VzdqaEMxSm52N2c=&i=NWYxNzBkMDNiNTVmZGEwZmIyNjczYmRm&t=TXRCZnZOZEtNRDYvN0R0QXpMUHh0ZVMzNU9HOTJFNnU5Nkk4aFNEa2NuST0=&h=03c9bbdd5a65430ebca772df08d7f2b1> >>> * Audiobombs: https://www.audiobombs.com/users/jeanette_c >>> <https://us-west-2.protection.sophos.com?d=audiobombs.com&u=aHR0cHM6Ly93d3cuYXVkaW9ib21icy5jb20vdXNlcnMvamVhbmV0dGVfYw==&i=NWYxNzBkMDNiNTVmZGEwZmIyNjczYmRm&t=emFIeXVKRkJiOGJ2c1BXVkJEc1hJVGdVUisxZ25OSU5zQXJ0dEQ5SnlXST0=&h=03c9bbdd5a65430ebca772df08d7f2b1> >>> * GitHub: https://github.com/jeanette-c >>> <https://us-west-2.protection.sophos.com?d=github.com&u=aHR0cHM6Ly9naXRodWIuY29tL2plYW5ldHRlLWM=&i=NWYxNzBkMDNiNTVmZGEwZmIyNjczYmRm&t=anhzMlhqbG9WcGEzdTRSdE1pYkdHb2lOSmFGUW9wYkZBMmJONXRaWGpyMD0=&h=03c9bbdd5a65430ebca772df08d7f2b1> >>> >>> I saw your smile >>> Stay with me a while <3 >>> (Britney Spears) >>> >>> Csound mailing list >>> Csound@listserv.heanet.ie >>> https://listserv.heanet.ie/cgi-bin/wa?A0=CSOUND >>> <https://us-west-2.protection.sophos.com?d=heanet.ie&u=aHR0cHM6Ly9saXN0c2Vydi5oZWFuZXQuaWUvY2dpLWJpbi93YT9BMD1DU09VTkQ=&i=NWYxNzBkMDNiNTVmZGEwZmIyNjczYmRm&t=WVZMRlI4dlFUVUZ6V2NTOUU5eE9lZnFIemtoc2hxYlBDMFFCWmtKZzhzRT0=&h=03c9bbdd5a65430ebca772df08d7f2b1> >>> Send bugs reports to >>> https://github.com/csound/csound/issues >>> <https://us-west-2.protection.sophos.com?d=github.com&u=aHR0cHM6Ly9naXRodWIuY29tL2Nzb3VuZC9jc291bmQvaXNzdWVz&i=NWYxNzBkMDNiNTVmZGEwZmIyNjczYmRm&t=YlNrQ2lLclRLZUpGUE1iR0FyY2M1eW1NTUU5SUozWlJwMTNZU2NXT1BLOD0=&h=03c9bbdd5a65430ebca772df08d7f2b1> >>> Discussions of bugs and features can be posted here >>> Csound mailing list Csound@listserv.heanet.ie >>> https://listserv.heanet.ie/cgi-bin/wa?A0=CSOUND >>> <https://us-west-2.protection.sophos.com?d=heanet.ie&u=aHR0cHM6Ly9saXN0c2Vydi5oZWFuZXQuaWUvY2dpLWJpbi93YT9BMD1DU09VTkQ=&i=NWYxNzBkMDNiNTVmZGEwZmIyNjczYmRm&t=WVZMRlI4dlFUVUZ6V2NTOUU5eE9lZnFIemtoc2hxYlBDMFFCWmtKZzhzRT0=&h=03c9bbdd5a65430ebca772df08d7f2b1> >>> Send bugs reports to https://github.com/csound/csound/issues >>> <https://us-west-2.protection.sophos.com?d=github.com&u=aHR0cHM6Ly9naXRodWIuY29tL2Nzb3VuZC9jc291bmQvaXNzdWVz&i=NWYxNzBkMDNiNTVmZGEwZmIyNjczYmRm&t=YlNrQ2lLclRLZUpGUE1iR0FyY2M1eW1NTUU5SUozWlJwMTNZU2NXT1BLOD0=&h=03c9bbdd5a65430ebca772df08d7f2b1> >>> Discussions of bugs and features can be posted here >> >> Csound mailing list Csound@listserv.heanet.ie >> https://listserv.heanet.ie/cgi-bin/wa?A0=CSOUND Send bugs reports to >> https://github.com/csound/csound/issues Discussions of bugs and features >> can be posted here > > Csound mailing list > Csound@listserv.heanet.ie > https://listserv.heanet.ie/cgi-bin/wa?A0=CSOUND > Send bugs reports to > https://github.com/csound/csound/issues > Discussions of bugs and features can be posted here > -- * Website: http://juliencoder.de - for summer is a state of sound * Youtube: https://www.youtube.com/channel/UCMS4rfGrTwz8W7jhC1Jnv7g * Audiobombs: https://www.audiobombs.com/users/jeanette_c * GitHub: https://github.com/jeanette-c When you need someone, you just turn around and I will be there <3 (Britney Spears) Csound mailing list Csound@listserv.heanet.ie https://listserv.heanet.ie/cgi-bin/wa?A0=CSOUND Send bugs reports to https://github.com/csound/csound/issues Discussions of bugs and features can be posted here Csound mailing list Csound@listserv.heanet.ie https://listserv.heanet.ie/cgi-bin/wa?A0=CSOUND Send bugs reports to https://github.com/csound/csound/issues Discussions of bugs and features can be posted here Csound mailing list Csound@listserv.heanet.ie https://listserv.heanet.ie/cgi-bin/wa?A0=CSOUND Send bugs reports to https://github.com/csound/csound/issues Discussions of bugs and features can be posted here Csound mailing list Csound@listserv.heanet.ie https://listserv.heanet.ie/cgi-bin/wa?A0=CSOUND Send bugs reports to https://github.com/csound/csound/issues Discussions of bugs and features can be posted here

Date	2021-09-23 15:57
From	Anders Genell
Subject	Re: [Csnd] Simplistic approximation of air absorption (cutoff frequency)
	Kicking some life in this old conversation, I just wanted to post a link to an article discussing calculation of air absorption, where there are some references to filter design that fairly well approximates the air absorption effect. Hopefully it could be useful to someone. https://rosap.ntl.bts.gov/view/dot/9810/dot_9810_DS1.pdf? Regards, Anders On Mon, Sep 13, 2021 at 11:01 PM Partev Sarkissian <0000060b2ef1338e-dmarc-request@listserv.heanet.ie> wrote: And leaving with a more real world low pass response. Butterworth curve, nice. -PBS -----Original Message----- From: Michael Gogins <michael.gogins@GMAIL.COM> To: CSOUND@LISTSERV.HEANET.IE Sent: Mon, Sep 13, 2021 1:53 pm Subject: Re: [Csnd] Simplistic approximation of air absorption (cutoff frequency) No, this part drops the highpass cutoff frequency by the inverse square of the radial distance from the source. Best, Mike ----------------------------------------------------- Michael Gogins Irreducible Productions http://michaelgogins.tumblr.com Michael dot Gogins at gmail dot com On Mon, Sep 13, 2021 at 3:01 PM Partev Sarkissian <0000060b2ef1338e-dmarc-request@listserv.heanet.ie> wrote: Very nice. dB drops off by inverse square of the the radial distance from the source? -PBS -----Original Message----- From: Jeanette C. <julien@MAIL.UPB.DE> To: CSOUND@LISTSERV.HEANET.IE Sent: Mon, Sep 13, 2021 5:46 am Subject: Re: [Csnd] Simplistic approximation of air absorption (cutoff frequency) Thanks Michael, this is exactly what I was looking for! This will get me going. Nice UDO. Best wishes, Jeanette Sep 13 2021, Michael Gogins has written: > I have used this approximation in my spatialization, borrowed mostly from > Jan Jacob Hoffmann. The idea is to filter more of the higher frequencies > with greater distance. > > ; Zero distance blows this up. > opcode LowpassByDistance, a, ak > asignal, kdistance xin > afiltered butterlp asignal, 22000 * sqrt(1.0 / kdistance) + .000001 > abalanced balance afiltered, asignal > xout abalanced > endop > > Regards, > Mike > > ----------------------------------------------------- > Michael Gogins > Irreducible Productions > http://michaelgogins.tumblr.com > Michael dot Gogins at gmail dot com > > > On Sun, Sep 12, 2021 at 6:14 PM Dr. Richard Boulanger < > rboulanger@berklee.edu> wrote: > >> Wow PBS, >> >> I am smiling from ear to ear as I read your advice and email. >> The Csound Community never ceases to amaze and inspire me. >> It is why I am so dedicated to sharing Csound with everyone - I want them >> to know and meet all of you! >> >> Have a great day. And thank you for making mine! >> >> - Dr.B >> >> >> Dr. Richard Boulanger >> >> Professor >> >> Electronic Production and Design >> >> Berklee College of Music >> >> Professional Writing & Technology Division >> >> >> On Sun, Sep 12, 2021 at 3:34 PM Partev Sarkissian < >> 0000060b2ef1338e-dmarc-request@listserv.heanet.ie> wrote: >> >>> >>> As I recall speed of sound is 1,130 ft/s, for 25° C, at 14.7 psi at >>> sea level (1966 standard). >>> >>> Don't know helpful that is, but it may be a place to start. >>> >>> >>> https://www.google.com/search?q=air+absorption&ie=utf-8&oe=utf-8&client=firefox-b-1 >>> >>> >>> https://ccrma.stanford.edu/~jos/pasp/Air_Absorption.html >>> From Julius Smith's book-3 "Physical Audio Signal Processing". >>> >>> https://en.wikipedia.org/wiki/Reynolds_number >>> A bit more esoteric. Used this a lot during my aeronautical engineer >>> study days, >>> to look at laminar to turbulent air flow over a surface (wing and body) >>> of an aircraft. >>> >>> Hope one or more of these helps. >>> >>> >>> -PBS >>> >>> >>> >>> -----Original Message----- >>> From: Jeanette C. <julien@MAIL.UPB.DE> >>> To: CSOUND@LISTSERV.HEANET.IE >>> Sent: Wed, Sep 8, 2021 5:39 pm >>> Subject: [Csnd] Simplistic approximation of air absorption (cutoff >>> frequency) >>> >>> Hey hey, >>> I am looking at acoustics and the effect of air absorption. Many sources >>> state >>> that it is only a perceptual factor in big spaces - or over long >>> distances), >>> but I haven't found a simple approximation for calculating a lowpass >>> filter >>> cutoff frequency. >>> >>> Does anyone perhaps have a good approximation or knows a source? I'd be >>> happy >>> with a calculation only based on distance, assuming some default pressure >>> and >>> humidity. >>> >>> Best wishes and TIA, >>> >>> Jeanette >>> >>> -- >>> * Website: http://juliencoder.de >>> <https://us-west-2.protection.sophos.com?d=juliencoder.de&u=aHR0cDovL2p1bGllbmNvZGVyLmRlLw==&i=NWYxNzBkMDNiNTVmZGEwZmIyNjczYmRm&t=S1czNHhhZE5yRWVaVVI0Vk9tYUJHRkdPZEhnOWVmTDdSc1VqTDltRVFOND0=&h=03c9bbdd5a65430ebca772df08d7f2b1>- >>> for summer is a state of sound >>> * Youtube: https://www.youtube.com/channel/UCMS4rfGrTwz8W7jhC1Jnv7g >>> <https://us-west-2.protection.sophos.com?d=youtube.com&u=aHR0cHM6Ly93d3cueW91dHViZS5jb20vY2hhbm5lbC9VQ01TNHJmR3JUd3o4VzdqaEMxSm52N2c=&i=NWYxNzBkMDNiNTVmZGEwZmIyNjczYmRm&t=TXRCZnZOZEtNRDYvN0R0QXpMUHh0ZVMzNU9HOTJFNnU5Nkk4aFNEa2NuST0=&h=03c9bbdd5a65430ebca772df08d7f2b1> >>> * Audiobombs: https://www.audiobombs.com/users/jeanette_c >>> <https://us-west-2.protection.sophos.com?d=audiobombs.com&u=aHR0cHM6Ly93d3cuYXVkaW9ib21icy5jb20vdXNlcnMvamVhbmV0dGVfYw==&i=NWYxNzBkMDNiNTVmZGEwZmIyNjczYmRm&t=emFIeXVKRkJiOGJ2c1BXVkJEc1hJVGdVUisxZ25OSU5zQXJ0dEQ5SnlXST0=&h=03c9bbdd5a65430ebca772df08d7f2b1> >>> * GitHub: https://github.com/jeanette-c >>> <https://us-west-2.protection.sophos.com?d=github.com&u=aHR0cHM6Ly9naXRodWIuY29tL2plYW5ldHRlLWM=&i=NWYxNzBkMDNiNTVmZGEwZmIyNjczYmRm&t=anhzMlhqbG9WcGEzdTRSdE1pYkdHb2lOSmFGUW9wYkZBMmJONXRaWGpyMD0=&h=03c9bbdd5a65430ebca772df08d7f2b1> >>> >>> I saw your smile >>> Stay with me a while <3 >>> (Britney Spears) >>> >>> Csound mailing list >>> Csound@listserv.heanet.ie >>> https://listserv.heanet.ie/cgi-bin/wa?A0=CSOUND >>> <https://us-west-2.protection.sophos.com?d=heanet.ie&u=aHR0cHM6Ly9saXN0c2Vydi5oZWFuZXQuaWUvY2dpLWJpbi93YT9BMD1DU09VTkQ=&i=NWYxNzBkMDNiNTVmZGEwZmIyNjczYmRm&t=WVZMRlI4dlFUVUZ6V2NTOUU5eE9lZnFIemtoc2hxYlBDMFFCWmtKZzhzRT0=&h=03c9bbdd5a65430ebca772df08d7f2b1> >>> Send bugs reports to >>> https://github.com/csound/csound/issues >>> <https://us-west-2.protection.sophos.com?d=github.com&u=aHR0cHM6Ly9naXRodWIuY29tL2Nzb3VuZC9jc291bmQvaXNzdWVz&i=NWYxNzBkMDNiNTVmZGEwZmIyNjczYmRm&t=YlNrQ2lLclRLZUpGUE1iR0FyY2M1eW1NTUU5SUozWlJwMTNZU2NXT1BLOD0=&h=03c9bbdd5a65430ebca772df08d7f2b1> >>> Discussions of bugs and features can be posted here >>> Csound mailing list Csound@listserv.heanet.ie >>> https://listserv.heanet.ie/cgi-bin/wa?A0=CSOUND >>> <https://us-west-2.protection.sophos.com?d=heanet.ie&u=aHR0cHM6Ly9saXN0c2Vydi5oZWFuZXQuaWUvY2dpLWJpbi93YT9BMD1DU09VTkQ=&i=NWYxNzBkMDNiNTVmZGEwZmIyNjczYmRm&t=WVZMRlI4dlFUVUZ6V2NTOUU5eE9lZnFIemtoc2hxYlBDMFFCWmtKZzhzRT0=&h=03c9bbdd5a65430ebca772df08d7f2b1> >>> Send bugs reports to https://github.com/csound/csound/issues >>> <https://us-west-2.protection.sophos.com?d=github.com&u=aHR0cHM6Ly9naXRodWIuY29tL2Nzb3VuZC9jc291bmQvaXNzdWVz&i=NWYxNzBkMDNiNTVmZGEwZmIyNjczYmRm&t=YlNrQ2lLclRLZUpGUE1iR0FyY2M1eW1NTUU5SUozWlJwMTNZU2NXT1BLOD0=&h=03c9bbdd5a65430ebca772df08d7f2b1> >>> Discussions of bugs and features can be posted here >> >> Csound mailing list Csound@listserv.heanet.ie >> https://listserv.heanet.ie/cgi-bin/wa?A0=CSOUND Send bugs reports to >> https://github.com/csound/csound/issues Discussions of bugs and features >> can be posted here > > Csound mailing list > Csound@listserv.heanet.ie > https://listserv.heanet.ie/cgi-bin/wa?A0=CSOUND > Send bugs reports to > https://github.com/csound/csound/issues > Discussions of bugs and features can be posted here > -- * Website: http://juliencoder.de - for summer is a state of sound * Youtube: https://www.youtube.com/channel/UCMS4rfGrTwz8W7jhC1Jnv7g * Audiobombs: https://www.audiobombs.com/users/jeanette_c * GitHub: https://github.com/jeanette-c When you need someone, you just turn around and I will be there <3 (Britney Spears) Csound mailing list Csound@listserv.heanet.ie https://listserv.heanet.ie/cgi-bin/wa?A0=CSOUND Send bugs reports to https://github.com/csound/csound/issues Discussions of bugs and features can be posted here Csound mailing list Csound@listserv.heanet.ie https://listserv.heanet.ie/cgi-bin/wa?A0=CSOUND Send bugs reports to https://github.com/csound/csound/issues Discussions of bugs and features can be posted here Csound mailing list Csound@listserv.heanet.ie https://listserv.heanet.ie/cgi-bin/wa?A0=CSOUND Send bugs reports to https://github.com/csound/csound/issues Discussions of bugs and features can be posted here Csound mailing list Csound@listserv.heanet.ie https://listserv.heanet.ie/cgi-bin/wa?A0=CSOUND Send bugs reports to https://github.com/csound/csound/issues Discussions of bugs and features can be posted here Csound mailing list Csound@listserv.heanet.ie https://listserv.heanet.ie/cgi-bin/wa?A0=CSOUND Send bugs reports to https://github.com/csound/csound/issues Discussions of bugs and features can be posted here

Date	2021-09-23 17:49
From	"Dr. Richard Boulanger"
Subject	Re: [Csnd] Simplistic approximation of air absorption (cutoff frequency)
	Thanks. - Dr.B Dr. Richard Boulanger Professor Electronic Production and Design Berklee College of Music Professional Writing & Technology Division On Thu, Sep 23, 2021 at 10:58 AM Anders Genell <anders.genell@gmail.com> wrote: Kicking some life in this old conversation, I just wanted to post a link to an article discussing calculation of air absorption, where there are some references to filter design that fairly well approximates the air absorption effect. Hopefully it could be useful to someone. https://rosap.ntl.bts.gov/view/dot/9810/dot_9810_DS1.pdf? Regards, Anders On Mon, Sep 13, 2021 at 11:01 PM Partev Sarkissian <0000060b2ef1338e-dmarc-request@listserv.heanet.ie> wrote: And leaving with a more real world low pass response. Butterworth curve, nice. -PBS -----Original Message----- From: Michael Gogins <michael.gogins@GMAIL.COM> To: CSOUND@LISTSERV.HEANET.IE Sent: Mon, Sep 13, 2021 1:53 pm Subject: Re: [Csnd] Simplistic approximation of air absorption (cutoff frequency) No, this part drops the highpass cutoff frequency by the inverse square of the radial distance from the source. Best, Mike ----------------------------------------------------- Michael Gogins Irreducible Productions http://michaelgogins.tumblr.com Michael dot Gogins at gmail dot com On Mon, Sep 13, 2021 at 3:01 PM Partev Sarkissian <0000060b2ef1338e-dmarc-request@listserv.heanet.ie> wrote: Very nice. dB drops off by inverse square of the the radial distance from the source? -PBS -----Original Message----- From: Jeanette C. <julien@MAIL.UPB.DE> To: CSOUND@LISTSERV.HEANET.IE Sent: Mon, Sep 13, 2021 5:46 am Subject: Re: [Csnd] Simplistic approximation of air absorption (cutoff frequency) Thanks Michael, this is exactly what I was looking for! This will get me going. Nice UDO. Best wishes, Jeanette Sep 13 2021, Michael Gogins has written: > I have used this approximation in my spatialization, borrowed mostly from > Jan Jacob Hoffmann. The idea is to filter more of the higher frequencies > with greater distance. > > ; Zero distance blows this up. > opcode LowpassByDistance, a, ak > asignal, kdistance xin > afiltered butterlp asignal, 22000 * sqrt(1.0 / kdistance) + .000001 > abalanced balance afiltered, asignal > xout abalanced > endop > > Regards, > Mike > > ----------------------------------------------------- > Michael Gogins > Irreducible Productions > http://michaelgogins.tumblr.com > Michael dot Gogins at gmail dot com > > > On Sun, Sep 12, 2021 at 6:14 PM Dr. Richard Boulanger < > rboulanger@berklee.edu> wrote: > >> Wow PBS, >> >> I am smiling from ear to ear as I read your advice and email. >> The Csound Community never ceases to amaze and inspire me. >> It is why I am so dedicated to sharing Csound with everyone - I want them >> to know and meet all of you! >> >> Have a great day. And thank you for making mine! >> >> - Dr.B >> >> >> Dr. Richard Boulanger >> >> Professor >> >> Electronic Production and Design >> >> Berklee College of Music >> >> Professional Writing & Technology Division >> >> >> On Sun, Sep 12, 2021 at 3:34 PM Partev Sarkissian < >> 0000060b2ef1338e-dmarc-request@listserv.heanet.ie> wrote: >> >>> >>> As I recall speed of sound is 1,130 ft/s, for 25° C, at 14.7 psi at >>> sea level (1966 standard). >>> >>> Don't know helpful that is, but it may be a place to start. >>> >>> >>> https://www.google.com/search?q=air+absorption&ie=utf-8&oe=utf-8&client=firefox-b-1 >>> >>> >>> https://ccrma.stanford.edu/~jos/pasp/Air_Absorption.html >>> From Julius Smith's book-3 "Physical Audio Signal Processing". >>> >>> https://en.wikipedia.org/wiki/Reynolds_number >>> A bit more esoteric. Used this a lot during my aeronautical engineer >>> study days, >>> to look at laminar to turbulent air flow over a surface (wing and body) >>> of an aircraft. >>> >>> Hope one or more of these helps. >>> >>> >>> -PBS >>> >>> >>> >>> -----Original Message----- >>> From: Jeanette C. <julien@MAIL.UPB.DE> >>> To: CSOUND@LISTSERV.HEANET.IE >>> Sent: Wed, Sep 8, 2021 5:39 pm >>> Subject: [Csnd] Simplistic approximation of air absorption (cutoff >>> frequency) >>> >>> Hey hey, >>> I am looking at acoustics and the effect of air absorption. Many sources >>> state >>> that it is only a perceptual factor in big spaces - or over long >>> distances), >>> but I haven't found a simple approximation for calculating a lowpass >>> filter >>> cutoff frequency. >>> >>> Does anyone perhaps have a good approximation or knows a source? I'd be >>> happy >>> with a calculation only based on distance, assuming some default pressure >>> and >>> humidity. >>> >>> Best wishes and TIA, >>> >>> Jeanette >>> >>> -- >>> * Website: http://juliencoder.de >>> <https://us-west-2.protection.sophos.com?d=juliencoder.de&u=aHR0cDovL2p1bGllbmNvZGVyLmRlLw==&i=NWYxNzBkMDNiNTVmZGEwZmIyNjczYmRm&t=S1czNHhhZE5yRWVaVVI0Vk9tYUJHRkdPZEhnOWVmTDdSc1VqTDltRVFOND0=&h=03c9bbdd5a65430ebca772df08d7f2b1>- >>> for summer is a state of sound >>> * Youtube: https://www.youtube.com/channel/UCMS4rfGrTwz8W7jhC1Jnv7g >>> <https://us-west-2.protection.sophos.com?d=youtube.com&u=aHR0cHM6Ly93d3cueW91dHViZS5jb20vY2hhbm5lbC9VQ01TNHJmR3JUd3o4VzdqaEMxSm52N2c=&i=NWYxNzBkMDNiNTVmZGEwZmIyNjczYmRm&t=TXRCZnZOZEtNRDYvN0R0QXpMUHh0ZVMzNU9HOTJFNnU5Nkk4aFNEa2NuST0=&h=03c9bbdd5a65430ebca772df08d7f2b1> >>> * Audiobombs: https://www.audiobombs.com/users/jeanette_c >>> <https://us-west-2.protection.sophos.com?d=audiobombs.com&u=aHR0cHM6Ly93d3cuYXVkaW9ib21icy5jb20vdXNlcnMvamVhbmV0dGVfYw==&i=NWYxNzBkMDNiNTVmZGEwZmIyNjczYmRm&t=emFIeXVKRkJiOGJ2c1BXVkJEc1hJVGdVUisxZ25OSU5zQXJ0dEQ5SnlXST0=&h=03c9bbdd5a65430ebca772df08d7f2b1> >>> * GitHub: https://github.com/jeanette-c >>> <https://us-west-2.protection.sophos.com?d=github.com&u=aHR0cHM6Ly9naXRodWIuY29tL2plYW5ldHRlLWM=&i=NWYxNzBkMDNiNTVmZGEwZmIyNjczYmRm&t=anhzMlhqbG9WcGEzdTRSdE1pYkdHb2lOSmFGUW9wYkZBMmJONXRaWGpyMD0=&h=03c9bbdd5a65430ebca772df08d7f2b1> >>> >>> I saw your smile >>> Stay with me a while <3 >>> (Britney Spears) >>> >>> Csound mailing list >>> Csound@listserv.heanet.ie >>> https://listserv.heanet.ie/cgi-bin/wa?A0=CSOUND >>> <https://us-west-2.protection.sophos.com?d=heanet.ie&u=aHR0cHM6Ly9saXN0c2Vydi5oZWFuZXQuaWUvY2dpLWJpbi93YT9BMD1DU09VTkQ=&i=NWYxNzBkMDNiNTVmZGEwZmIyNjczYmRm&t=WVZMRlI4dlFUVUZ6V2NTOUU5eE9lZnFIemtoc2hxYlBDMFFCWmtKZzhzRT0=&h=03c9bbdd5a65430ebca772df08d7f2b1> >>> Send bugs reports to >>> https://github.com/csound/csound/issues >>> <https://us-west-2.protection.sophos.com?d=github.com&u=aHR0cHM6Ly9naXRodWIuY29tL2Nzb3VuZC9jc291bmQvaXNzdWVz&i=NWYxNzBkMDNiNTVmZGEwZmIyNjczYmRm&t=YlNrQ2lLclRLZUpGUE1iR0FyY2M1eW1NTUU5SUozWlJwMTNZU2NXT1BLOD0=&h=03c9bbdd5a65430ebca772df08d7f2b1> >>> Discussions of bugs and features can be posted here >>> Csound mailing list Csound@listserv.heanet.ie >>> https://listserv.heanet.ie/cgi-bin/wa?A0=CSOUND >>> <https://us-west-2.protection.sophos.com?d=heanet.ie&u=aHR0cHM6Ly9saXN0c2Vydi5oZWFuZXQuaWUvY2dpLWJpbi93YT9BMD1DU09VTkQ=&i=NWYxNzBkMDNiNTVmZGEwZmIyNjczYmRm&t=WVZMRlI4dlFUVUZ6V2NTOUU5eE9lZnFIemtoc2hxYlBDMFFCWmtKZzhzRT0=&h=03c9bbdd5a65430ebca772df08d7f2b1> >>> Send bugs reports to https://github.com/csound/csound/issues >>> <https://us-west-2.protection.sophos.com?d=github.com&u=aHR0cHM6Ly9naXRodWIuY29tL2Nzb3VuZC9jc291bmQvaXNzdWVz&i=NWYxNzBkMDNiNTVmZGEwZmIyNjczYmRm&t=YlNrQ2lLclRLZUpGUE1iR0FyY2M1eW1NTUU5SUozWlJwMTNZU2NXT1BLOD0=&h=03c9bbdd5a65430ebca772df08d7f2b1> >>> Discussions of bugs and features can be posted here >> >> Csound mailing list Csound@listserv.heanet.ie >> https://listserv.heanet.ie/cgi-bin/wa?A0=CSOUND Send bugs reports to >> https://github.com/csound/csound/issues Discussions of bugs and features >> can be posted here > > Csound mailing list > Csound@listserv.heanet.ie > https://listserv.heanet.ie/cgi-bin/wa?A0=CSOUND > Send bugs reports to > https://github.com/csound/csound/issues > Discussions of bugs and features can be posted here > -- * Website: http://juliencoder.de - for summer is a state of sound * Youtube: https://www.youtube.com/channel/UCMS4rfGrTwz8W7jhC1Jnv7g * Audiobombs: https://www.audiobombs.com/users/jeanette_c * GitHub: https://github.com/jeanette-c When you need someone, you just turn around and I will be there <3 (Britney Spears) Csound mailing list Csound@listserv.heanet.ie https://listserv.heanet.ie/cgi-bin/wa?A0=CSOUND Send bugs reports to https://github.com/csound/csound/issues Discussions of bugs and features can be posted here Csound mailing list Csound@listserv.heanet.ie https://listserv.heanet.ie/cgi-bin/wa?A0=CSOUND Send bugs reports to https://github.com/csound/csound/issues Discussions of bugs and features can be posted here Csound mailing list Csound@listserv.heanet.ie https://listserv.heanet.ie/cgi-bin/wa?A0=CSOUND Send bugs reports to https://github.com/csound/csound/issues Discussions of bugs and features can be posted here Csound mailing list Csound@listserv.heanet.ie https://listserv.heanet.ie/cgi-bin/wa?A0=CSOUND Send bugs reports to https://github.com/csound/csound/issues Discussions of bugs and features can be posted here Csound mailing list Csound@listserv.heanet.ie https://listserv.heanet.ie/cgi-bin/wa?A0=CSOUND Send bugs reports to https://github.com/csound/csound/issues Discussions of bugs and features can be posted here Csound mailing list Csound@listserv.heanet.ie https://listserv.heanet.ie/cgi-bin/wa?A0=CSOUND Send bugs reports to https://github.com/csound/csound/issues Discussions of bugs and features can be posted here

Date	2021-09-23 17:58
From	Partev Sarkissian <0000060b2ef1338e-dmarc-request@LISTSERV.HEANET.IE>
Subject	Re: [Csnd] Simplistic approximation of air absorption (cutoff frequency)
	Very cool. Seen a paper like this one before. I think there's this info in a vest pocket reference book I have. Will have to check that when I get home. Very good. -PBS -----Original Message----- From: Anders Genell <anders.genell@GMAIL.COM> To: CSOUND@LISTSERV.HEANET.IE Sent: Thu, Sep 23, 2021 7:57 am Subject: Re: [Csnd] Simplistic approximation of air absorption (cutoff frequency) Kicking some life in this old conversation, I just wanted to post a link to an article discussing calculation of air absorption, where there are some references to filter design that fairly well approximates the air absorption effect. Hopefully it could be useful to someone. https://rosap.ntl.bts.gov/view/dot/9810/dot_9810_DS1.pdf? Regards, Anders On Mon, Sep 13, 2021 at 11:01 PM Partev Sarkissian <0000060b2ef1338e-dmarc-request@listserv.heanet.ie> wrote: And leaving with a more real world low pass response. Butterworth curve, nice. -PBS -----Original Message----- From: Michael Gogins <michael.gogins@GMAIL.COM> To: CSOUND@LISTSERV.HEANET.IE Sent: Mon, Sep 13, 2021 1:53 pm Subject: Re: [Csnd] Simplistic approximation of air absorption (cutoff frequency) No, this part drops the highpass cutoff frequency by the inverse square of the radial distance from the source. Best, Mike ----------------------------------------------------- Michael Gogins Irreducible Productions http://michaelgogins.tumblr.com Michael dot Gogins at gmail dot com On Mon, Sep 13, 2021 at 3:01 PM Partev Sarkissian <0000060b2ef1338e-dmarc-request@listserv.heanet.ie> wrote: Very nice. dB drops off by inverse square of the the radial distance from the source? -PBS -----Original Message----- From: Jeanette C. <julien@MAIL.UPB.DE> To: CSOUND@LISTSERV.HEANET.IE Sent: Mon, Sep 13, 2021 5:46 am Subject: Re: [Csnd] Simplistic approximation of air absorption (cutoff frequency) Thanks Michael, this is exactly what I was looking for! This will get me going. Nice UDO. Best wishes, Jeanette Sep 13 2021, Michael Gogins has written: > I have used this approximation in my spatialization, borrowed mostly from > Jan Jacob Hoffmann. The idea is to filter more of the higher frequencies > with greater distance. > > ; Zero distance blows this up. > opcode LowpassByDistance, a, ak > asignal, kdistance xin > afiltered butterlp asignal, 22000 * sqrt(1.0 / kdistance) + .000001 > abalanced balance afiltered, asignal > xout abalanced > endop > > Regards, > Mike > > ----------------------------------------------------- > Michael Gogins > Irreducible Productions > http://michaelgogins.tumblr.com > Michael dot Gogins at gmail dot com > > > On Sun, Sep 12, 2021 at 6:14 PM Dr. Richard Boulanger < > rboulanger@berklee.edu> wrote: > >> Wow PBS, >> >> I am smiling from ear to ear as I read your advice and email. >> The Csound Community never ceases to amaze and inspire me. >> It is why I am so dedicated to sharing Csound with everyone - I want them >> to know and meet all of you! >> >> Have a great day. And thank you for making mine! >> >> - Dr.B >> >> >> Dr. Richard Boulanger >> >> Professor >> >> Electronic Production and Design >> >> Berklee College of Music >> >> Professional Writing & Technology Division >> >> >> On Sun, Sep 12, 2021 at 3:34 PM Partev Sarkissian < >> 0000060b2ef1338e-dmarc-request@listserv.heanet.ie> wrote: >> >>> >>> As I recall speed of sound is 1,130 ft/s, for 25° C, at 14.7 psi at >>> sea level (1966 standard). >>> >>> Don't know helpful that is, but it may be a place to start. >>> >>> >>> https://www.google.com/search?q=air+absorption&ie=utf-8&oe=utf-8&client=firefox-b-1 >>> >>> >>> https://ccrma.stanford.edu/~jos/pasp/Air_Absorption.html >>> From Julius Smith's book-3 "Physical Audio Signal Processing". >>> >>> https://en.wikipedia.org/wiki/Reynolds_number >>> A bit more esoteric. Used this a lot during my aeronautical engineer >>> study days, >>> to look at laminar to turbulent air flow over a surface (wing and body) >>> of an aircraft. >>> >>> Hope one or more of these helps. >>> >>> >>> -PBS >>> >>> >>> >>> -----Original Message----- >>> From: Jeanette C. <julien@MAIL.UPB.DE> >>> To: CSOUND@LISTSERV.HEANET.IE >>> Sent: Wed, Sep 8, 2021 5:39 pm >>> Subject: [Csnd] Simplistic approximation of air absorption (cutoff >>> frequency) >>> >>> Hey hey, >>> I am looking at acoustics and the effect of air absorption. Many sources >>> state >>> that it is only a perceptual factor in big spaces - or over long >>> distances), >>> but I haven't found a simple approximation for calculating a lowpass >>> filter >>> cutoff frequency. >>> >>> Does anyone perhaps have a good approximation or knows a source? I'd be >>> happy >>> with a calculation only based on distance, assuming some default pressure >>> and >>> humidity. >>> >>> Best wishes and TIA, >>> >>> Jeanette >>> >>> -- >>> * Website: http://juliencoder.de >>> <https://us-west-2.protection.sophos.com?d=juliencoder.de&u=aHR0cDovL2p1bGllbmNvZGVyLmRlLw==&i=NWYxNzBkMDNiNTVmZGEwZmIyNjczYmRm&t=S1czNHhhZE5yRWVaVVI0Vk9tYUJHRkdPZEhnOWVmTDdSc1VqTDltRVFOND0=&h=03c9bbdd5a65430ebca772df08d7f2b1>- >>> for summer is a state of sound >>> * Youtube: https://www.youtube.com/channel/UCMS4rfGrTwz8W7jhC1Jnv7g >>> <https://us-west-2.protection.sophos.com?d=youtube.com&u=aHR0cHM6Ly93d3cueW91dHViZS5jb20vY2hhbm5lbC9VQ01TNHJmR3JUd3o4VzdqaEMxSm52N2c=&i=NWYxNzBkMDNiNTVmZGEwZmIyNjczYmRm&t=TXRCZnZOZEtNRDYvN0R0QXpMUHh0ZVMzNU9HOTJFNnU5Nkk4aFNEa2NuST0=&h=03c9bbdd5a65430ebca772df08d7f2b1> >>> * Audiobombs: https://www.audiobombs.com/users/jeanette_c >>> <https://us-west-2.protection.sophos.com?d=audiobombs.com&u=aHR0cHM6Ly93d3cuYXVkaW9ib21icy5jb20vdXNlcnMvamVhbmV0dGVfYw==&i=NWYxNzBkMDNiNTVmZGEwZmIyNjczYmRm&t=emFIeXVKRkJiOGJ2c1BXVkJEc1hJVGdVUisxZ25OSU5zQXJ0dEQ5SnlXST0=&h=03c9bbdd5a65430ebca772df08d7f2b1> >>> * GitHub: https://github.com/jeanette-c >>> <https://us-west-2.protection.sophos.com?d=github.com&u=aHR0cHM6Ly9naXRodWIuY29tL2plYW5ldHRlLWM=&i=NWYxNzBkMDNiNTVmZGEwZmIyNjczYmRm&t=anhzMlhqbG9WcGEzdTRSdE1pYkdHb2lOSmFGUW9wYkZBMmJONXRaWGpyMD0=&h=03c9bbdd5a65430ebca772df08d7f2b1> >>> >>> I saw your smile >>> Stay with me a while <3 >>> (Britney Spears) >>> >>> Csound mailing list >>> Csound@listserv.heanet.ie >>> https://listserv.heanet.ie/cgi-bin/wa?A0=CSOUND >>> <https://us-west-2.protection.sophos.com?d=heanet.ie&u=aHR0cHM6Ly9saXN0c2Vydi5oZWFuZXQuaWUvY2dpLWJpbi93YT9BMD1DU09VTkQ=&i=NWYxNzBkMDNiNTVmZGEwZmIyNjczYmRm&t=WVZMRlI4dlFUVUZ6V2NTOUU5eE9lZnFIemtoc2hxYlBDMFFCWmtKZzhzRT0=&h=03c9bbdd5a65430ebca772df08d7f2b1> >>> Send bugs reports to >>> https://github.com/csound/csound/issues >>> <https://us-west-2.protection.sophos.com?d=github.com&u=aHR0cHM6Ly9naXRodWIuY29tL2Nzb3VuZC9jc291bmQvaXNzdWVz&i=NWYxNzBkMDNiNTVmZGEwZmIyNjczYmRm&t=YlNrQ2lLclRLZUpGUE1iR0FyY2M1eW1NTUU5SUozWlJwMTNZU2NXT1BLOD0=&h=03c9bbdd5a65430ebca772df08d7f2b1> >>> Discussions of bugs and features can be posted here >>> Csound mailing list Csound@listserv.heanet.ie >>> https://listserv.heanet.ie/cgi-bin/wa?A0=CSOUND >>> <https://us-west-2.protection.sophos.com?d=heanet.ie&u=aHR0cHM6Ly9saXN0c2Vydi5oZWFuZXQuaWUvY2dpLWJpbi93YT9BMD1DU09VTkQ=&i=NWYxNzBkMDNiNTVmZGEwZmIyNjczYmRm&t=WVZMRlI4dlFUVUZ6V2NTOUU5eE9lZnFIemtoc2hxYlBDMFFCWmtKZzhzRT0=&h=03c9bbdd5a65430ebca772df08d7f2b1> >>> Send bugs reports to https://github.com/csound/csound/issues >>> <https://us-west-2.protection.sophos.com?d=github.com&u=aHR0cHM6Ly9naXRodWIuY29tL2Nzb3VuZC9jc291bmQvaXNzdWVz&i=NWYxNzBkMDNiNTVmZGEwZmIyNjczYmRm&t=YlNrQ2lLclRLZUpGUE1iR0FyY2M1eW1NTUU5SUozWlJwMTNZU2NXT1BLOD0=&h=03c9bbdd5a65430ebca772df08d7f2b1> >>> Discussions of bugs and features can be posted here >> >> Csound mailing list Csound@listserv.heanet.ie >> https://listserv.heanet.ie/cgi-bin/wa?A0=CSOUND Send bugs reports to >> https://github.com/csound/csound/issues Discussions of bugs and features >> can be posted here > > Csound mailing list > Csound@listserv.heanet.ie > https://listserv.heanet.ie/cgi-bin/wa?A0=CSOUND > Send bugs reports to > https://github.com/csound/csound/issues > Discussions of bugs and features can be posted here > -- * Website: http://juliencoder.de - for summer is a state of sound * Youtube: https://www.youtube.com/channel/UCMS4rfGrTwz8W7jhC1Jnv7g * Audiobombs: https://www.audiobombs.com/users/jeanette_c * GitHub: https://github.com/jeanette-c When you need someone, you just turn around and I will be there <3 (Britney Spears) Csound mailing list Csound@listserv.heanet.ie https://listserv.heanet.ie/cgi-bin/wa?A0=CSOUND Send bugs reports to https://github.com/csound/csound/issues Discussions of bugs and features can be posted here Csound mailing list Csound@listserv.heanet.ie https://listserv.heanet.ie/cgi-bin/wa?A0=CSOUND Send bugs reports to https://github.com/csound/csound/issues Discussions of bugs and features can be posted here Csound mailing list Csound@listserv.heanet.ie https://listserv.heanet.ie/cgi-bin/wa?A0=CSOUND Send bugs reports to https://github.com/csound/csound/issues Discussions of bugs and features can be posted here Csound mailing list Csound@listserv.heanet.ie https://listserv.heanet.ie/cgi-bin/wa?A0=CSOUND Send bugs reports to https://github.com/csound/csound/issues Discussions of bugs and features can be posted here Csound mailing list Csound@listserv.heanet.ie https://listserv.heanet.ie/cgi-bin/wa?A0=CSOUND Send bugs reports to https://github.com/csound/csound/issues Discussions of bugs and features can be posted here Csound mailing list Csound@listserv.heanet.ie https://listserv.heanet.ie/cgi-bin/wa?A0=CSOUND Send bugs reports to https://github.com/csound/csound/issues Discussions of bugs and features can be posted here