Strictly speaking, phase shift is a shift in time. You are really asking
about a reversal of polarity. It's helpful to keep the distinction
clear.

I believe the short answer to your question is No, but when I went to
look it up, I just got confused.

I'm looking at "The Science of Musical Sound", a GREAT book by John R.
Pierce, ISBN 0-7167-1508-2, appendix E, "Reflection of Waves", and I
can't figure it out. There's a diagram which seems to suggest that no,
the polarity does not reverse. This makes intuitive sense: the peak of a
wave (i.e. maximum air pressure) hits the wall and bounces off. When it
starts moving away from the wall, it is still a peak of increased
pressure. How could it instanly become a decrease in pressure?

But then, on the next page (p. 210), there's a note that reads:
"We see that, in reflection from a solid obstacle, the pressure of a
sound wave is reversed." This seems to have something to do with the
relationship between the signs of pressure and velocity. Quite frankly I
don't understand what this means, and it seems to contradict the
diagram. Sorry!

Regards,

Well, I'll try with the theory that a sound reverts when it reflects..
I'm experimenting on how the ear/brain calculates the vertical distance from a
audiosource, but I haven't really read anything about it.


>But then, on the next page (p. 210), there's a note that reads:
>"We see that, in reflection from a solid obstacle, the pressure of a
>sound wave is reversed." This seems to have something to do with the
>relationship between the signs of pressure and velocity. Quite frankly I
>don't understand what this means, and it seems to contradict the
>diagram. Sorry!

.--- -- -  -
| Anders "Pipe/Nature" Andersson, pipe@algonet.se
:











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From: Derek Pierce 
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Subject: Re: Phaseshift at sound reflection?
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Hi Anders
I  remember reading that the vertical placement of sound is recognised by the
effect that the ears shape has on it .Sound reaching us from variuos heights is
filtered by the ear to a different degree depending on its height.
Derek Pierce

Anders Andersson wrote:

> Well, I'll try with the theory that a sound reverts when it reflects..
> I'm experimenting on how the ear/brain calculates the vertical distance from a
> audiosource, but I haven't really read anything about it.
>
> >But then, on the next page (p. 210), there's a note that reads:
> >"We see that, in reflection from a solid obstacle, the pressure of a
> >sound wave is reversed." This seems to have something to do with the
> >relationship between the signs of pressure and velocity. Quite frankly I
> >don't understand what this means, and it seems to contradict the
> >diagram. Sorry!
>
> .--- -- -  -
> | Anders "Pipe/Nature" Andersson, pipe@algonet.se
> :













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From: bdewitt 
Cc: CSound list 
Subject: RE: Phaseshift at sound reflection?
Date: Sat, 3 Oct 1998 11:55:19 -0400
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	I've read, and have had demonstrated to me, that sounds along the vertical
plane are distinguished by clues other than sound. In other words, when
sound is the only clue, you can only tell left and right, not up, down,
front or back.
	A friend with a little beeper won $5 proving this to me. One test, when he
convinced me that the beeper was in front of me, I clearly 'heard' that it
was in front of me, when in fact it was above me.

http://www.TheImageMill.com

> -----Original Message-----
> From: owner-csound-outgoing@maths.ex.ac.uk
> [mailto:owner-csound-outgoing@maths.ex.ac.uk]On Behalf Of Derek Pierce
> Sent: Saturday, October 03, 1998 5:49 PM
> To: pipe@algonet.se
> Cc: CSound list
> Subject: Re: Phaseshift at sound reflection?
>
>
> Hi Anders
> I  remember reading that the vertical placement of sound is
> recognised by the
> effect that the ears shape has on it .Sound reaching us from
> variuos heights is
> filtered by the ear to a different degree depending on its height.
> Derek Pierce
>
> Anders Andersson wrote:
>
> > Well, I'll try with the theory that a sound reverts when it reflects..
> > I'm experimenting on how the ear/brain calculates the vertical
> distance from a
> > audiosource, but I haven't really read anything about it.
> >
> > >But then, on the next page (p. 210), there's a note that reads:
> > >"We see that, in reflection from a solid obstacle, the pressure of a
> > >sound wave is reversed." This seems to have something to do with the
> > >relationship between the signs of pressure and velocity. Quite
> frankly I
> > >don't understand what this means, and it seems to contradict the
> > >diagram. Sorry!
> >
> > .--- -- -  -
> > | Anders "Pipe/Nature" Andersson, pipe@algonet.se
> > :
>
>
>
>











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From: Yair Kass 
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That's DirectCsound 2.0.
If anybody was wondering.

yair

Yair Kass wrote:

> Hi,
>    I would like to run one of my codes, written for RTCsound,
>    on DirectCsound, and it seems like everything works
>    except that some MIDI controllers (Peavey PC1600), work
>    and others don't.(e.g. controller no. 1 is suddenly inactivated).  It
> was bug free on RT.
>
>    Does DirectCsound have problems with certain controller .numbers ?
>    Did I miss anything basic regarding MIDI and the move to DirectCS ?
>
>    It was hard to tell at the state I was, but that apeared to be my
> only problem.
>
>    Any advise ?
>
>    Yair.













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Subject: Re: Phaseshift at sound reflection?
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Hi,
Derek Pierce wrote:

> I  remember reading that the vertical placement of sound is recognised by the
> effect that the ears shape has on it .Sound reaching us from variuos heights is
> filtered by the ear to a different degree depending on its height.
> Derek Pierce

The skin of the ear acts as a bandpass filter. Since it is asymmetrical
about each axis, clues are gained about where the sound is coming from,
(up, down, in front, behind). I have heard this demonstrated by
synthesising a shallow bandpass filter, (about 3dB I think) and sweeping
it up and down over a noise source. The reason the bleeper idea wouldn't
work I suspect is that there was an insufficient number of frequencies
in the source. Incidentally you must close off one ear, (stick your
finger in it) to hear the effect. No, it's not a joke- you really hear
the sound seem to go up and down. It also works on headphones.










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From: Tobiah 
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This is more of a UNIX question then a Csound
question, but I am interested in furthering
the discussion about handling floating point
wave files.

Now that .wav floats are supported, I am trying
to put together a couple of shell wrappers that
will make manipulating and playing them a bit
easier to handle.

I came up with this script as a cheap floating
point sound player:

        SCALE_AMOUNT=`scale $1 | grep 'Max scale factor' | cut -d'='
-f2`
        scale -W -s -o/dsp -F$SCALE_AMOUNT $1 &
        vplay /dsp

where '/dsp' is a fifo which is world r/w-able.
When I attempt this, scale dies with 'error writing Wave header'.

I don't understand why, because I can do this:

        cp sound.wav /dsp &
        vplay /dsp

This plays the sound.  I don't like the idea of temp files as much,
because of the disk space requirements, and the lack of a
synchronization
between the processes such as the fifo provides.  

What might be nice would be the filename trick that csound uses to 
pipe to a process (-o '|vplay').  Any other suggestions?

Thanks

Toby

        -There otta be a law-










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Date: Sat, 3 Oct 1998 17:49:59 -0700 (PDT)
From: Chris Brown 
Subject: Re: MIDI controller
To: csound@maths.ex.ac.uk, Josep M Comajuncosas 
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Hi Joe,

By programmer I meant computer programmer.  The PG-1000 sends out
short system exclusive messages. You would have to write a program in
C, C++, or BASIC to read the PG-1000 sysex messages translate them to
what you want and then re-transmit them thru something like Hubees
loopback to your sequencer, Csound or keyboard.

Chris




---Josep M Comajuncosas  wrote:
>
> Chris Brown wrote:
>=20
> > It's not a dedicated MIDI controller box but the Roland JP8000 has
> >
> > 30 sliders and nobs (assignable to MIDI controllers)
> > 10 or so switches (they send out sys ex data though)
> >
> > ribbon controller
> > pitch bend/mod lever
> > 49 key keyboard
> > Digital Analog synth
> > Arpeggiator
> >
> > They run around $1300.00.
>=20
> Too much for me... I=B4d be rather interested in an autonomous ribbon
> controller, together with a wind controller, some foot pedals and
knobs and
> sliders... and maybe a keyboard ;-)
>=20
> > Another idea if you are a programmer is to buy an old Roland
PG-1000.
> > I got mine for $100.00 It has 56 sliders and a few buttons that send
> > out sysex data.
>=20
> Ok, I=B4ll look for this... are the sliders assignable to any
controller ?
> $100 is really affordable!
>=20
>=20

_________________________________________________________
DO YOU YAHOO!?
Get your free @yahoo.com address at http://mail.yahoo.com











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From: Anders Andersson 
Reply-To: pipe@algonet.se
To: d.pierce@bathspa.ac.uk
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Date: Sun, 04 Oct 1998 13:43:16 +0100
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Hmm... this might be something..
The problem is to find the right parameters for the BP-Filter.

My first experiment was to simulate the first ground-reflection,
but it didn't work. (That's why the question about how the sound
reflects)

Does anyone have any data's regarding on how the head act as a filter?
(rolloff etc)

.--- -- -  -
| Anders "Pipe/Nature" Andersson, pipe@algonet.se
:



>> I  remember reading that the vertical placement of sound is recognised by
>the
>> effect that the ears shape has on it .Sound reaching us from variuos
heights
>is
>> filtered by the ear to a different degree depending on its height.
>> Derek Pierce

>The skin of the ear acts as a bandpass filter. Since it is asymmetrical
>about each axis, clues are gained about where the sound is coming from,
>(up, down, in front, behind). I have heard this demonstrated by
>synthesising a shallow bandpass filter, (about 3dB I think) and sweeping
>it up and down over a noise source. The reason the bleeper idea wouldn't
>work I suspect is that there was an insufficient number of frequencies
>in the source. Incidentally you must close off one ear, (stick your
>finger in it) to hear the effect. No, it's not a joke- you really hear
>the sound seem to go up and down. It also works on headphones.