[Stk] RTAUDIO Float64 vs 32 vs Integer SoundCard

[Gary Worsham]

Thanks Perry.  My next step is trying to get the "Duplex" (pass thru)
working.  For comparison, the pure generators sound fine. I agree that
building up a step at time is probably the only way to go.  And it sure
gets one's feet wet with the code!

Gary W.

On Sun, Aug 28, 2016 at 9:31 AM, Perry Cook <prc at cs.princeton.edu> wrote:

> Hey Gary,
>
> I’m feeling that this is likely not at the root of your audio crunchiness.
> And I’m pretty certain that hard-wiring INT into format would not work.
> STK assumes floats in the rough range +/- 1.0 throughout, and only
> the last layer of the audio interface worries about getting it out to the
> sound card.  I didn’t check all the RTAudio code but I think that format
> type might be more wide-reaching than just the last audio hardware
> layer.
>
> Spits and Fizzles on EFX sounds more like buffer/IO problems to me,
> unless it’s purely signal (level) dependent, and in that case it sounds
> more like clipping.  Starting with EFX, which has I/O and signal
> processing, has too many potential areas for problems to happen
> to be sure where things might be going wrong.  Maybe try a simpler
> demo yet (in the examples folder), like the single sine oscillator, or
> playsimp on a really simple (sine wave ideally) .wav file.  Play with
> the gain a bit (from within the code) and see if clipping or other
> interruption occurs.  If you can get it to make a pure sine wave in
> real time that sounds like a pure sine wave (or play any sound file
> without distortion/clipping), then the FORMAT/32/64 is likely not the
> problem.
>
> Others please chime in if you have experience in this area.
>
> PRC
>
> > On Aug 27, 2016, at 5:51 PM, Gary Worsham <gary.worsham at gmail.com>
> wrote:
> >
> > I understand I'm still messing around at the RtAudio stage, but I
> promise to ask some stk questions just as soon as I get this other stuff
> out of the way.
> >
> > I accomplished 2 different things.
> >
> > #1 I figured out how to determine the index of the USB interface and use
> this instead of "default" when picking the audio interface to use.
> >
> > #2 I figured out how to get the USB interface down to the default
> position.  At least, let's say I changed some things and it's there but I
> couldn't actually explain it.  So now this interface is used by default
> with the stk example programs.  Yay!
> >
> > Next issue is that for example, I am running "effects" via StkEffects.
> The sound is very crunchy - not overdriven, but spits and fizzles with any
> signal at all.  I noticed in the effects.cpp:
> >
> > effects.cpp:  RtAudioFormat format = ( sizeof(StkFloat) == 8 ) ?
> RTAUDIO_FLOAT64 : RTAUDIO_FLOAT32;
> >
> > So we are choosing float 64 or float 32 format based on a runtime
> decision... however this particular interface only supports 32 bit int.
> Seems like this code assumes support for 32 or 64 bit float.
> >
> > Should I just hard-wire RTAUDIO_SINT32 in here to get started, or do I
> have to change the code itself to accommodate this?
> >
> > Thanks,
> >
> > Gary W.
> > _______________________________________________
> > Stk mailing list
> > Stk at ccrma.stanford.edu
> > https://cm-mail.stanford.edu/mailman/listinfo/stk
>
>
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