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[Csnd] Delayed convolution

Date2018-04-02 19:28
FromRuben Sverre Gjertsen
Subject[Csnd] Delayed convolution
Hello,

I’m trying convolution with impulse responses, and I’m having the problem that the whole reverb is delayed about 12 seconds from the original sound. The delays in the impulse response files are always less than a second, why do they become so much longer with ‘convolve’? 
The soundfiles are 96 kHz, 4 channel B-format, analyzed with cvanal (default settings). I’m not sure I have a program to open and visualize cvanal files to see what’s going on.

This is how the convolution is applied to a first order b-format coming from global variables:
aw   convolve arin1*kamp, ifilcod,1
ax    convolve arin2*kamp, ifilcod,2
ay   convolve arin3*kamp, ifilcod,3
az    convolve arin4*kamp, ifilcod,4

A negative delay could have solved the problem non-realtime:
aw delay aw,-12 
ax delay ax,-12 
ay delay ay,-12 
az delay az,-12 

But that was not legal:
:: INIT ERROR in instr 99: illegal delay time
:: aw	delay	aw	-12	0	
:

Best
Ruben
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Date2018-04-02 19:44
Fromjpff
SubjectRe: [Csnd] Delayed convolution
I asume you read the manual?  It states

..... Determine initial delay, if any, of impulse response. If the impulse 
response has not had the initial delay removed, then you can skip this 
step. If it has been removed, then the only way you will know the initial 
delay is if the information has been provided separately. For this 
example, let's assume that the initial delay is 60ms (0.06s)

Determine the required delay to apply to the dry signal, to align it with 
the convolved signal:


   If kr = 441:
         1/kr = 0.0023, which is <= IRdur (1.379s), so:
         Delay1  = ceil(IRdur * kr) / kr
                 = ceil(608.14) / 441
                 = 609/441
                 = 1.38s


   Accounting for the initial delay:
         Delay2  = 0.06s
    Total delay  = delay1 - delay2
                 = 1.38 - 0.06
                 = 1.32s
.............

It is some time since I used it but it did seem to solve my problems with 
the delay.

Not sure that helps!

On Mon, 2 Apr 2018, Ruben Sverre Gjertsen wrote:

> Hello,
>
> I’m trying convolution with impulse responses, and I’m having the problem that the whole reverb is delayed about 12 seconds from the original sound. The delays in the impulse response files are always less than a second, why do they become so much longer with ‘convolve’?
> The soundfiles are 96 kHz, 4 channel B-format, analyzed with cvanal (default settings). I’m not sure I have a program to open and visualize cvanal files to see what’s going on.
>
> This is how the convolution is applied to a first order b-format coming from global variables:
> aw   convolve arin1*kamp, ifilcod,1
> ax    convolve arin2*kamp, ifilcod,2
> ay   convolve arin3*kamp, ifilcod,3
> az    convolve arin4*kamp, ifilcod,4
>
> A negative delay could have solved the problem non-realtime:
> aw delay aw,-12
> ax delay ax,-12
> ay delay ay,-12
> az delay az,-12
>
> But that was not legal:
> :: INIT ERROR in instr 99: illegal delay time
> :: aw	delay	aw	-12	0
> :
>
> Best
> Ruben
> 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
>

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Date2018-04-02 19:51
Fromjpff
SubjectRe: [Csnd] Delayed convolution
Not sure about in ambisonics but my use delays te dry signal not the 
convolved one

On Mon, 2 Apr 2018, Ruben Sverre Gjertsen wrote:

> Hello,
>
> I’m trying convolution with impulse responses, and I’m having the problem that the whole reverb is delayed about 12 seconds from the original sound. The delays in the impulse response files are always less than a second, why do they become so much longer with ‘convolve’?
> The soundfiles are 96 kHz, 4 channel B-format, analyzed with cvanal (default settings). I’m not sure I have a program to open and visualize cvanal files to see what’s going on.
>
> This is how the convolution is applied to a first order b-format coming from global variables:
> aw   convolve arin1*kamp, ifilcod,1
> ax    convolve arin2*kamp, ifilcod,2
> ay   convolve arin3*kamp, ifilcod,3
> az    convolve arin4*kamp, ifilcod,4
>
> A negative delay could have solved the problem non-realtime:
> aw delay aw,-12
> ax delay ax,-12
> ay delay ay,-12
> az delay az,-12
>
> But that was not legal:
> :: INIT ERROR in instr 99: illegal delay time
> :: aw	delay	aw	-12	0
> :
>
> Best
> Ruben
> 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
>

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Date2018-04-02 21:35
Fromjoachim heintz
SubjectRe: [Csnd] Delayed convolution
yes, delay the dry signal.  or, if non-realtime, perhaps simply render 
the convolve to a file and mix both later.  then it is also no problem 
to adjust the delay.



On 02/04/18 20:51, jpff wrote:
> Not sure about in ambisonics but my use delays te dry signal not the
> convolved one
>
> On Mon, 2 Apr 2018, Ruben Sverre Gjertsen wrote:
>
>> Hello,
>>
>> I’m trying convolution with impulse responses, and I’m having the
>> problem that the whole reverb is delayed about 12 seconds from the
>> original sound. The delays in the impulse response files are always
>> less than a second, why do they become so much longer with ‘convolve’?
>> The soundfiles are 96 kHz, 4 channel B-format, analyzed with cvanal
>> (default settings). I’m not sure I have a program to open and
>> visualize cvanal files to see what’s going on.
>>
>> This is how the convolution is applied to a first order b-format
>> coming from global variables:
>> aw   convolve arin1*kamp, ifilcod,1
>> ax    convolve arin2*kamp, ifilcod,2
>> ay   convolve arin3*kamp, ifilcod,3
>> az    convolve arin4*kamp, ifilcod,4
>>
>> A negative delay could have solved the problem non-realtime:
>> aw delay aw,-12
>> ax delay ax,-12
>> ay delay ay,-12
>> az delay az,-12
>>
>> But that was not legal:
>> :: INIT ERROR in instr 99: illegal delay time
>> :: aw    delay    aw    -12    0
>> :
>>
>> Best
>> Ruben
>> 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

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Date2018-04-03 17:37
FromSteven Yi
SubjectRe: [Csnd] Delayed convolution
Also, perhaps try pconvolve?

On Mon, Apr 2, 2018 at 4:35 PM, joachim heintz  wrote:
> yes, delay the dry signal.  or, if non-realtime, perhaps simply render the
> convolve to a file and mix both later.  then it is also no problem to adjust
> the delay.
>
>
>
>
> On 02/04/18 20:51, jpff wrote:
>>
>> Not sure about in ambisonics but my use delays te dry signal not the
>> convolved one
>>
>> On Mon, 2 Apr 2018, Ruben Sverre Gjertsen wrote:
>>
>>> Hello,
>>>
>>> I’m trying convolution with impulse responses, and I’m having the
>>> problem that the whole reverb is delayed about 12 seconds from the
>>> original sound. The delays in the impulse response files are always
>>> less than a second, why do they become so much longer with ‘convolve’?
>>> The soundfiles are 96 kHz, 4 channel B-format, analyzed with cvanal
>>> (default settings). I’m not sure I have a program to open and
>>> visualize cvanal files to see what’s going on.
>>>
>>> This is how the convolution is applied to a first order b-format
>>> coming from global variables:
>>> aw   convolve arin1*kamp, ifilcod,1
>>> ax    convolve arin2*kamp, ifilcod,2
>>> ay   convolve arin3*kamp, ifilcod,3
>>> az    convolve arin4*kamp, ifilcod,4
>>>
>>> A negative delay could have solved the problem non-realtime:
>>> aw delay aw,-12
>>> ax delay ax,-12
>>> ay delay ay,-12
>>> az delay az,-12
>>>
>>> But that was not legal:
>>> :: INIT ERROR in instr 99:  [millegal delay time [m
>>> ::  [maw    delay    aw    -12    0
>>> :
>>>
>>> Best
>>> Ruben
>>> 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

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