This seems like a problem in general on Windows, but Pd still seems to give me the option to use Multiple Devices in the Audio Settings.

I feel like I've been able to do this before, despite the repeated console warning:

separate audio device choice not supported; using sequential devices.

but now when I try it I can only get the audio input of the first device. Is there any way to get both? If not, why is this option here? Is setting up some kind of virtual sound card to combine the different devices into one the only way of doing this? (and if so, what do you recommend?)

@whale-av Hey, thank you. It works well for about five minutes and then the sound gets glitchy/noisy for a couple of minutes bit before returning to normal for a while.

In the ASIO4ALL advanced settings, I have the following toggled on:

PreSonus AudioBox iTwo
---Out 2x 44.1kHz 24Bits
Logicool BRIO (webcam)
BOSS GP-10
---IN(GP-10)

*ASIO Buffer Size is 512 for everything
*Latency compensation is set to 32 samples in and out
*Allow Pull Mode is off
*Always Resample 44.1kHz<->48Hz is off (PD is running in 44.1kHz)
*Force WDM Driver to 16 Bit

Any idea what could be wrong? I guess I could try ditching the BRIO webcam's audio for a mic that goes into the Presonus if reducing the amount of devices from three to two would help.

@s.elliot.perez I will dig out a soundard when I get home late this evening and have a look at my settings and post what I can.
The only thing I remember is that using my Motu828 I have Pd Delay (msec) set to 2 as I am needing very low latency, and that I have a lower buffer size.... 128 I think.
Is the Asio4all tray icon staying green when you get glitches? or flashing red?
Do you have a card trying to be the master clock? I think I let my computer do the clock.
It can be a bit trial and error but I remember the Asio4all manual being quite good.
David.

@whale-av Just double-checked and no, it stays green when it glitches.

I just used the USBView app recommended by the ASIO4All documentation and it looks like all three of my devices have at least one line of "bmAttributes" where it says that "Synchronization Type = Asynchronous", which I guess means that they don't sync with my computer's clock and are thus causing this problem. Am I out of luck?

@s.elliot.perez Asynchronous shouldn't give noticeable clicks. Every now and then a sample will be repeated, or dropped but that is not normally audible.
Windows I think does audio internally at 48.... so maybe try the "resample" set to on.
Clicks are usually too small a buffer.... but 512 should be good. If you are not worried about latency for your project then try setting it higher as one of the devices might not be able to process in time..
David.

@whale-av OK, I tried raising latency t0 1024 and setting everything to 48k. The result is that it gets noisy sooner (in a rhythmic, pulsing way). Here are screenshots of my settings. See anything else that might be wrong?

I tried returning PD to 44.1k and turning off resample while leaving latency at 1024, but it's the same as the original problem....

@s.elliot.perez My setup looks like this..... but different soundcards of course...... and only 2 including the built-in Realtek.


I needed very low latency.... so extreme Delay (msec) of 2 setting for Pd....... and an ASIO buffer of 64.

I notice that I have selected all the stereo pairs for the Motu...... rather than the "whole device" that you have chosen for the GP-10.
I would try turning on only one device at a time in Asio4all and making sure that the buffer sizes all match in the dedicated control panels for those soundcards that have one. But I think you posted that the buffers matched.
Ticking the callbacks box in Pd might help.
I cannot see anything "wrong" in your screenshots.
You could try using this DPC latency checking program to see if interrupts or dodgy drivers are causing problems.........DPC latency check.zip
Lastly, modern computers often use internal usb ports for the mouse, keyboard, bluetooth etc.
Changing external port so that you are using a different hub could also help.
Where are you hearing the glitches.... on one device or all?
David.

@whale-av

OK, after hours of messing with this, the solution is quite simple... as you can see in the screenshots of my previous post, the block size in Pure Data is 64 while the size in the ASIO4All settings is 1024. Making sure these values match (in the Presonus control panel too) and setting them to 512 seems to work (setting it lower doesn't seem to work, the webcam audio is probably holding the other devices back) . Thanks for giving me some ideas!

@whale-av Do you ever find yourself unable to close or save a patch if you turn off DSP while using ASIO4All?

@s.elliot.perez said:

@whale-av Do you ever find yourself unable to close or save a patch if you turn off DSP while using ASIO4All? This happens consistently, even when ASIO4ALL is working, and I have to do a force quit.

@s.elliot.perez Not exactly that. I found that (windows) pd.exe often stayed in memory when closed while using Asio4all.... causing a problem when I reopened Pd with of course the same asio setup.
I should check whether that happens if callbacks are not used.

I only use asio for shows.... and I always start up with a batch file that specifies all the settings that I need for Pd and the audio out.... using pd.com (I can't remember why!... getting old).
e.g.

"C:\Program Files (x86)\pd\bin\pd.com" -path C:\Users\David\Desktop\PDMusic\Minx -path C:\Program_Files_(x86)\pd\extra\readanysf~\ -r 44100 -asio -nomidi -audioindev 15 -audiooutdev 12 -inchannels 32 -outchannels 22 -audiobuf 2 -blocksize 64 -callback -nosleep -open Minx_Run.pd
exit`

All of my show patches loadbang a [perf 1( message to Pd which asks for confirmation to close or quit.... in case I make a mistake during the show.
So it is easiest to just close the dos cmd window when finished..... which shuts down Pd without questions.
Since working that way I no longer have Pd hanging in the background.
Maybe check your task manager to see whether you have the same situation.... and see whether callbacks on/off changes anything.

I will experiment to see whether I can reproduce your problem though. It will not surprise me to find that I can. I have never turned off dsp for the whole of Pd while running a patch.
David.
P.S. If you do have time code problems between sound cards and they have spdif connections then you can sync them by connecting a cable between the output of one (master) and the input of the other (slave). Some in-built soundcards can use the headphone jack to send spdif.
The clock is derived from the stream..... possible because of the spdif format.