[PD] 0 latency

[marius schebella]

Frank Barknecht wrote:
> Hallo,
> Juan Felipe Mejia hat gesagt: // Juan Felipe Mejia wrote:
> 
>> hi everyone, im a beggining to work with Puredata and a TD 9 Roland v- 
>> drums.
>> I'm using a MOTU ultralite mk3 as my in-out audio divice.
>> I work with a MacBook Pro, 2.5 Ghz Intel core duo, 4 GB of ram.
>>
>> Until now almost everything is working properly but the latency.
>> Does anyone now how to get the 0 latency en puredata?
> 
> Zero latency is impossible in a computer software if you do some
> processing of the incoming data before sending it out again.
> 
>> i've tried to reduce the sample rate to 30000 and even lower, the same  
>> with the delay but there is still some latency.
>> Lower than 30000 works better but the sound quality is bad.
> 
> Generally latency shrinks with higher samplerates and gets larger with
> lower rates, provided you have the same blocksize. 
> 
>> I tried AudioDesk (the software that comes with the MOTU) to make some  
>> live recordings and there were no delay, no latency.
> 
> Probably the soundcard is sending incoming data straight through, so no
> processing is going on. Otherwise see above: Technically 0 latency is
> impossible.

but a buffer of 64 samples at a sampling frequency of 96kHz should be 
possible. that would mean a latency of 0.67 ms, which is the time in 
which sound travels 0,22 meters. if you use headphones, then this means 
you hear sound earlier than from an instrument (like a piano, which is 
maybe one meter away).
marius.