Hi List, I have a question regarding a patch that I made for recording multi-channel audio. For the 16 channels, we are using Fireface 800 with an extension board. It works quite well! For a specific application, we are trying to use the two iMic's with a USB plug to record at least 4 channel audio. When I initialize PD and select the audio settings, it shows me two of these seperately in the option, the recording for one works but not for the other! The question is if I can use PD to record simultaneously from two different source from a single patch or somehow get the recording from both! regards, Tania
Hi Tania,
are you able to record from two different soundcards simultaneously in any other application on your computer? I ask because this isn't usually the case in my experience. Many have dreamed of linking several "el cheapo" soundcards to get an inexpensive multichannel soundcard from them. Two (or more) different soundcards have two different sample clocks and these won't be in sync, among the main problems. Google "el cheapo soundcard", or check here:
http://quicktoots.linuxaudio.org/toots/el-cheapo/
To see how this might be accomplished on Linux. There, it requires the hardware modification of removing the clock from one card and connecting it to the clock of one master card.
And I quote:
The challenge in recording with more than one soundcard at once in any computer under any operating system is to make the cards syncronize. The actual sample rate of each card is depending on the crystal used in the card. To cut the component cost of consumer grade soundcards cheap crystals, with wider tolerances than those used in pro equipment, are often used. As a result, when using two cards at once one can have a real sample rate of 44.099 kHz in one card and a samplerate of 44.101 kHz in the other. This is no problem when recording with one card only, but the difference in the sample rates will cause phase shifts in the recording when using two cards. Phase shifts make the high frequencies of the recording e.g. cymbals sound bad. Further, not all audio drivers can drive cards that are not in exact samplerate sync.
Some pro-cards come equipped with a link to connect multiple cards to run in sync. Consumer cards do not have this feature. This Howto describes a simple hardware modification to create such a synchronisation link between consumer grade cards. Without hardware modifications it is very difficult to ensure the cards are in sync.
You haven't mentioned the operating system you are running, BTW...
Maybe other operating systems allow multiple (consumer) soundcard recording, I haven't tried. In PD, I don't think it's possible. If you had a way of getting your two IMics to be seen as one soundcard (the Linux el cheapo method), then you could try it.
best, d.
tania habib wrote:
Hi List, I have a question regarding a patch that I made for recording multi-channel audio. For the 16 channels, we are using Fireface 800 with an extension board. It works quite well! For a specific application, we are trying to use the two iMic's with a USB plug to record at least 4 channel audio. When I initialize PD and select the audio settings, it shows me two of these seperately in the option, the recording for one works but not for the other! The question is if I can use PD to record simultaneously from two different source from a single patch or somehow get the recording from both! regards, Tania
PD-list@iem.at mailing list UNSUBSCRIBE and account-management -> http://lists.puredata.info/listinfo/pd-list
Hi Derek, I am working on Mac Pro osx 10.4, I have not tried the two different soundcards option, we use the multichannel sound card for our recordings. But we wanted to try the recording with iMic's, do you know a link or a way to link two or multiple iMics together?
Thanks for the link, it looks interesting, I will check it out in detail but this is not the direction we want to proceed at the moment. tania
On Dec 18, 2007 12:06 PM, Derek Holzer derek@umatic.nl wrote:
Hi Tania,
are you able to record from two different soundcards simultaneously in any other application on your computer? I ask because this isn't usually the case in my experience. Many have dreamed of linking several "el cheapo" soundcards to get an inexpensive multichannel soundcard from them. Two (or more) different soundcards have two different sample clocks and these won't be in sync, among the main problems. Google "el cheapo soundcard", or check here:
http://quicktoots.linuxaudio.org/toots/el-cheapo/
To see how this might be accomplished on Linux. There, it requires the hardware modification of removing the clock from one card and connecting it to the clock of one master card.
And I quote:
The challenge in recording with more than one soundcard at once in any computer under any operating system is to make the cards syncronize. The actual sample rate of each card is depending on the crystal used in the card. To cut the component cost of consumer grade soundcards cheap crystals, with wider tolerances than those used in pro equipment, are often used. As a result, when using two cards at once one can have a real sample rate of 44.099 kHz in one card and a samplerate of 44.101 kHz in the other. This is no problem when recording with one card only, but the difference in the sample rates will cause phase shifts in the recording when using two cards. Phase shifts make the high frequencies of the recording e.g. cymbals sound bad. Further, not all audio drivers can drive cards that are not in exact samplerate sync.
Some pro-cards come equipped with a link to connect multiple cards to run in sync. Consumer cards do not have this feature. This Howto describes a simple hardware modification to create such a synchronisation link between consumer grade cards. Without hardware modifications it is very difficult to ensure the cards are in sync.
You haven't mentioned the operating system you are running, BTW...
Maybe other operating systems allow multiple (consumer) soundcard recording, I haven't tried. In PD, I don't think it's possible. If you had a way of getting your two IMics to be seen as one soundcard (the Linux el cheapo method), then you could try it.
best, d.
tania habib wrote:
Hi List, I have a question regarding a patch that I made for recording multi-channel audio. For the 16 channels, we are using Fireface 800 with an extension board. It works quite well! For a specific application, we are trying to use the two iMic's with a USB plug to record at least 4 channel audio. When I initialize PD and select the audio settings, it shows me two of these seperately in the option, the recording for one works but not for the other! The question is if I can use PD to record simultaneously from two different source from a single patch or somehow get the recording from both! regards, Tania
PD-list@iem.at mailing list UNSUBSCRIBE and account-management -> http://lists.puredata.info/listinfo/pd-list
-- derek holzer ::: http://www.umatic.nl ::: http://blog.myspace.com/macumbista ---Oblique Strategy # 94: "Is it finished?"
tania habib wrote:
Hi Derek, I am working on Mac Pro osx 10.4,
http://www.apple.com/pro/techniques/aggregateaudio/
Hope this helps,
Claude
I have not tried the two different soundcards option, we use the multichannel sound card for our recordings. But we wanted to try the recording with iMic's, do you know a link or a way to link two or multiple iMics together?
Thanks for the link, it looks interesting, I will check it out in detail but this is not the direction we want to proceed at the moment. tania
On Dec 18, 2007 12:06 PM, Derek Holzer derek@umatic.nl wrote:
Hi Tania,
are you able to record from two different soundcards simultaneously in any other application on your computer? I ask because this isn't usually the case in my experience. Many have dreamed of linking several "el cheapo" soundcards to get an inexpensive multichannel soundcard from them. Two (or more) different soundcards have two different sample clocks and these won't be in sync, among the main problems. Google "el cheapo soundcard", or check here:
http://quicktoots.linuxaudio.org/toots/el-cheapo/
To see how this might be accomplished on Linux. There, it requires the hardware modification of removing the clock from one card and connecting it to the clock of one master card.
And I quote:
The challenge in recording with more than one soundcard at once in any computer under any operating system is to make the cards syncronize. The actual sample rate of each card is depending on the crystal used in the card. To cut the component cost of consumer grade soundcards cheap crystals, with wider tolerances than those used in pro equipment, are often used. As a result, when using two cards at once one can have a real sample rate of 44.099 kHz in one card and a samplerate of 44.101 kHz in the other. This is no problem when recording with one card only, but the difference in the sample rates will cause phase shifts in the recording when using two cards. Phase shifts make the high frequencies of the recording e.g. cymbals sound bad. Further, not all audio drivers can drive cards that are not in exact samplerate sync.
Some pro-cards come equipped with a link to connect multiple cards to run in sync. Consumer cards do not have this feature. This Howto describes a simple hardware modification to create such a synchronisation link between consumer grade cards. Without hardware modifications it is very difficult to ensure the cards are in sync.
You haven't mentioned the operating system you are running, BTW...
Maybe other operating systems allow multiple (consumer) soundcard recording, I haven't tried. In PD, I don't think it's possible. If you had a way of getting your two IMics to be seen as one soundcard (the Linux el cheapo method), then you could try it.
best, d.
tania habib wrote:
Hi List, I have a question regarding a patch that I made for recording multi-channel audio. For the 16 channels, we are using Fireface 800 with an extension board. It works quite well! For a specific application, we are trying to use the two iMic's with a USB plug to record at least 4 channel audio. When I initialize PD and select the audio settings, it shows me two of these seperately in the option, the recording for one works but not for the other! The question is if I can use PD to record simultaneously from two different source from a single patch or somehow get the recording from both! regards, Tania
PD-list@iem.at mailing list UNSUBSCRIBE and account-management -> http://lists.puredata.info/listinfo/pd-list
-- derek holzer ::: http://www.umatic.nl ::: http://blog.myspace.com/macumbista ---Oblique Strategy # 94: "Is it finished?"
PD-list@iem.at mailing list UNSUBSCRIBE and account-management -> http://lists.puredata.info/listinfo/pd-list
Well, I think the iMic definitely counts as one of the cheapest soundcards on the market, so I'm sure that the problems discussed on the website could occur. Mismatched sample rates can actually crash the audio drivers if they drift too far apart, as well as cause noticeable phase shifting. Maybe this Aggregate Audio program which Claude mentions can help you. Please report back, especially on whether or not high frequency phasing happens with this approach. I'm curious.
best, d.
tania habib wrote:
Hi Derek, I am working on Mac Pro osx 10.4, I have not tried the two different soundcards option, we use the multichannel sound card for our recordings. But we wanted to try the recording with iMic's, do you know a link or a way to link two or multiple iMics together?
Have you remembered to start as pd -audioindev 1,2,3,4 ?
On Tue, 18 Dec 2007 12:22:40 +0100 "tania habib" taniahabib@gmail.com wrote:
Hi Derek, I am working on Mac Pro osx 10.4, I have not tried the two different soundcards option, we use the multichannel sound card for our recordings. But we wanted to try the recording with iMic's, do you know a link or a way to link two or multiple iMics together?
Thanks for the link, it looks interesting, I will check it out in detail but this is not the direction we want to proceed at the moment. tania
On Dec 18, 2007 12:06 PM, Derek Holzer derek@umatic.nl wrote:
Hi Tania,
are you able to record from two different soundcards simultaneously in any other application on your computer? I ask because this isn't usually the case in my experience. Many have dreamed of linking several "el cheapo" soundcards to get an inexpensive multichannel soundcard from them. Two (or more) different soundcards have two different sample clocks and these won't be in sync, among the main problems. Google "el cheapo soundcard", or check here:
http://quicktoots.linuxaudio.org/toots/el-cheapo/
To see how this might be accomplished on Linux. There, it requires the hardware modification of removing the clock from one card and connecting it to the clock of one master card.
And I quote:
The challenge in recording with more than one soundcard at once in any computer under any operating system is to make the cards syncronize. The actual sample rate of each card is depending on the crystal used in the card. To cut the component cost of consumer grade soundcards cheap crystals, with wider tolerances than those used in pro equipment, are often used. As a result, when using two cards at once one can have a real sample rate of 44.099 kHz in one card and a samplerate of 44.101 kHz in the other. This is no problem when recording with one card only, but the difference in the sample rates will cause phase shifts in the recording when using two cards. Phase shifts make the high frequencies of the recording e.g. cymbals sound bad. Further, not all audio drivers can drive cards that are not in exact samplerate sync.
Some pro-cards come equipped with a link to connect multiple cards to run in sync. Consumer cards do not have this feature. This Howto describes a simple hardware modification to create such a synchronisation link between consumer grade cards. Without hardware modifications it is very difficult to ensure the cards are in sync.
You haven't mentioned the operating system you are running, BTW...
Maybe other operating systems allow multiple (consumer) soundcard recording, I haven't tried. In PD, I don't think it's possible. If you had a way of getting your two IMics to be seen as one soundcard (the Linux el cheapo method), then you could try it.
best, d.
tania habib wrote:
Hi List, I have a question regarding a patch that I made for recording multi-channel audio. For the 16 channels, we are using Fireface 800 with an extension board. It works quite well! For a specific application, we are trying to use the two iMic's with a USB plug to record at least 4 channel audio. When I initialize PD and select the audio settings, it shows me two of these seperately in the option, the recording for one works but not for the other! The question is if I can use PD to record simultaneously from two different source from a single patch or somehow get the recording from both! regards, Tania
PD-list@iem.at mailing list UNSUBSCRIBE and account-management -> http://lists.puredata.info/listinfo/pd-list
-- derek holzer ::: http://www.umatic.nl ::: http://blog.myspace.com/macumbista ---Oblique Strategy # 94: "Is it finished?"
PD-list@iem.at mailing list UNSUBSCRIBE and account-management -> http://lists.puredata.info/listinfo/pd-list
On 18 Dec 2007, at 10:22 PM, tania habib wrote:
I am working on Mac Pro osx 10.4, I have not tried the two different soundcards option, we use the multichannel sound card for our recordings.
the OSX audio system does have a system to join two different soundcards
-open Audio MIDI Setup (usually in the Utilities folder)
-then open the Aggregate Devices Editor from the Audio menu
- here you can create a new device, select which will be the
master clock etc
-this new device can then be selected and used in the usual manner
simon
the OSX audio system does have a system to join two different soundcards -open Audio MIDI Setup (usually in the Utilities folder) -then open the Aggregate Devices Editor from the Audio menu - here you can create a new device, select which will be the master clock etc -this new device can then be selected and used in the usual manner
Yes! I have tried it and it seems to work now, as Pd recognizes this aggregate device, I have to do a detailed recording session, to exactly see how well suited it will be for the application Thanks this option really seems to works well!!
tania
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Andy Farnell -
Claude Heiland-Allen -
Derek Holzer -
simon wise -
tania habib