[LAT] To much latency

Jeremy Jongepier jeremy at autostatic.com
Sun Oct 30 14:19:37 UTC 2011

On 10/30/2011 03:13 PM, Dave Stikkolorum wrote:
> I have jack 1.9.7
> if I increase to 48000 qjackctl gives 42.7 ms. (21.3 when using 512/period)

You can decrease the latency by lowering the number of frames. It is now 
set to 1024, try 256 or even lower. I use a setting of 64 or 128 when 
using a MIDI keyboard with a softsynth or sampler.

> how would i see the improvement with /usr/bin/jackd -S ?
> it doesn't change the expected latency in qjackctl when I do that.

No that's right. But it might improve performance of JACK regarding 
xruns. -S means Synchronous or basically the ol' Jack1 way, some 
soundcards work better that way.

> One of the annoying things is the delay between the midi keyboard
> and the actual sound. I guess it has to do with the one we are tuning
> now, right?

Yes, the lower the latency, the lower the delay between pressing a key 
and hearing the actual sound. With a frames setting of 64 at 48Khz 
system latency will drop to 2.67 ms (64/48000*2). Those are the kind of 
latencies you want when using a MIDI keyboard.



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