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1
Dear Mario,

I tried these two different setup with the PsychPortAudio with PTB 3.0.08 and win XP:


InitializePsychSound(1);
>> pahandle = PsychPortAudio('Open', 3, [], 2, 44100, 2);
PTB-INFO: New audio device with handle 3 opened as PortAudio stream:
PTB-INFO: For 2 channels Playback: Audio subsystem is MME, Audio device name is ASUS Xonar DG Audio
PTB-INFO: Real samplerate 44100.000000 Hz. Input latency 0.000000 msecs, Output latency 116.099773 msecs.


InitializePsychSound(1);
>> pahandle = PsychPortAudio('Open', [], [], 2, 44100, 2);
PTB-INFO: New audio device with handle 4 opened as PortAudio stream:
PTB-INFO: For 2 channels Playback: Audio subsystem is ASIO, Audio device name is Xonar DG ASIO
PTB-INFO: Real samplerate 44100.000000 Hz. Input latency 1.451247 msecs, Output latency 2.902494 msecs.

In the first case, with device n°3, the output latency seems very high, compared to the case default device. To what is due this big output latency difference?
Furthermore, when the device is selected by default [], there is no sound? Any suggestion?

Thank you very much!

best,
fosco

2
--- In psychtoolbox@yahoogroups.com, fosco bernasconi <fosco.bernasconi@...> wrote:
>
> Dear Mario,
>
> I tried these two different setup with the PsychPortAudio with PTB 3.0.08
> and win XP:
>
>
> InitializePsychSound(1);
> >> pahandle = PsychPortAudio('Open', 3, [], 2, 44100, 2);
> PTB-INFO: New audio device with handle 3 opened as PortAudio stream:
> PTB-INFO: For 2 channels Playback: Audio subsystem is MME, Audio device
> name is ASUS Xonar DG Audio
> PTB-INFO: Real samplerate 44100.000000 Hz. Input latency 0.000000 msecs,
> Output latency 116.099773 msecs.
>
>
> InitializePsychSound(1);
> >> pahandle = PsychPortAudio('Open', [], [], 2, 44100, 2);
> PTB-INFO: New audio device with handle 4 opened as PortAudio stream:
> PTB-INFO: For 2 channels Playback: Audio subsystem is ASIO, Audio device
> name is Xonar DG ASIO
> PTB-INFO: Real samplerate 44100.000000 Hz. Input latency 1.451247 msecs,
> Output latency 2.902494 msecs.
>
> In the first case, with device n°3, the output latency seems very high,
> compared to the case default device. To what is due this big output latency
> difference?
> Furthermore, when the device is selected by default [], there is no sound?
> Any suggestion?
>
> Thank you very much!
>
> best,
> fosco
>
3
> --- In psychtoolbox@yahoogroups.com, fosco bernasconi <fosco.bernasconi@> wrote:
> >
> > Dear Mario,
> >
> > I tried these two different setup with the PsychPortAudio with PTB 3.0.08
> > and win XP:
> >
> >
> > InitializePsychSound(1);
> > >> pahandle = PsychPortAudio('Open', 3, [], 2, 44100, 2);
> > PTB-INFO: New audio device with handle 3 opened as PortAudio stream:
> > PTB-INFO: For 2 channels Playback: Audio subsystem is MME, Audio device
> > name is ASUS Xonar DG Audio
> > PTB-INFO: Real samplerate 44100.000000 Hz. Input latency 0.000000 msecs,
> > Output latency 116.099773 msecs.
> >
> >
> > InitializePsychSound(1);
> > >> pahandle = PsychPortAudio('Open', [], [], 2, 44100, 2);
> > PTB-INFO: New audio device with handle 4 opened as PortAudio stream:
> > PTB-INFO: For 2 channels Playback: Audio subsystem is ASIO, Audio device
> > name is Xonar DG ASIO
> > PTB-INFO: Real samplerate 44100.000000 Hz. Input latency 1.451247 msecs,
> > Output latency 2.902494 msecs.
> >
> > In the first case, with device n°3, the output latency seems very high,
> > compared to the case default device. To what is due this big output latency
> > difference?

Because in the ASIO case you use a driver designed by audio professionals, and in the first MME case you use a driver developed by the mentally challenged people who used to work at Microsoft when Windows 95 was "designed". That's why you need an ASIO card + driver to get reasonable performance on Windows. The internet will tell you more.

> > Furthermore, when the device is selected by default [], there is no sound?
> > Any suggestion?

First, if you really still use PTB 3.0.8 as you stated, update it to 3.0.10, because everything older is unsupported. Then follow suggestions made on the forum in the past for resolving audio problems, i won't repeat myself this time, we went through this procedures multiple times on the forum. A first start would be to check if our demos, e.g., PsychPortAudioTimingTest work, and go from there.

ciao,
-mario


> >
> > Thank you very much!
> >
> > best,
> > fosco
> >
>