Hi, I am just wondering is it possible to achieve zero latency audio playback, from the time you call the Play function and the time it actually comes out through the DAC. Is it possible for that time to be 0?
Posted on 2002-12-27 19:58:39 by x86asm

I'm supposed to know. ( http://www.infinito.it/utenti/bizzetti/dsprt/faq.html )

In short, the smallest latency you can get is in the order of 16-18 samples, on the usually found AC97 CODECs that use Sigma-Delta technology. More details on the FAQ (look for ~zero latency)
Posted on 2002-12-28 02:41:19 by Maverick
Did you write that software?! Excellent I was thinking of doing some coding for the EMU10K1 but my Live! is nt working :(

You access the hardware directly but unfortunately I dont have that blessing :)

What is a reasonable delay for the user witnessing something and actually hearing the sound effect. 20~40ms? I can get about 20~40ms latency. Is that sufficient?
Posted on 2002-12-28 09:55:21 by x86asm

In my (someway picky) experience I set it to 10 ms. A bit greater could be fine, but not always. Remember, the human hear is a complex non-linear system.

Consider that if you're playing an electric guitar, with the amp at 3 meters from your ears, that the delay in sound propagation equivals to about 10 ms.
Posted on 2002-12-28 16:32:24 by Maverick
huh,
latency less than 20ms is unnecessary. I tested Dreamer as a sampler at 30ms , with a virtual piano keyboard software -> mouse clicks produce MIDI messages to MidiYoke, which sends message to Dreamer, and the latter waits until all other processing is done, and then processes the message. The result is hearing the new note immediately as you press the mouse button (latency of 30ms is immediate for the human ear).
I have read somewhere that the ear's fastest response is 67ms. Latency of zero can be achieved, I suppose, if DMA is not being used , if the cpu is all the time in the thread that processes sound, and .. you use a very good soundcard :). But anyway, latency below 20 is unnecessary!
Posted on 2003-01-01 19:32:49 by Ultrano
latency less than 20ms is unnecessary
That is a totally subjective opinion.
Let away that, for example, in a large hall, if you have your amp's speakers at 30 meters of distance, which already amounts to 10 ms, you're already 10 ms off your subjective threshold.

Another example is that (at least my DspRT proggy) isn't specifically tied to music applications, but is a general DSP tool (e.g. to control attuators via feedback).

I suggest you to read some good book on psychoacoustics (like e.g. Psychoacoustics, 2nd ed, by Zwicker & Fastl) for an introduction on how very differently the ear behaves on different frequences, transients and loudness.

In any case I think you will agree that having less latency doesn't hurt anybody.. you can always use a delay to simulate more (but you can't simulate less on a system which has already latency).

I have read somewhere that the ear's fastest response is 67ms.
Where did you read it? That's totally misleading, and probably refers to the physical response to transients (e.g. "when you hear the click, move the finger").
Latency of zero can be achieved, I suppose, if DMA is not being used , if the cpu is all the time in the thread that processes sound.
Exactly. ;)
But anyway, latency below 20 is unnecessary!
Again, what is necessary and what is unnecessary is a totally subjective argument.
Posted on 2003-01-02 03:50:45 by Maverick