Latency increases over a period of time

keymasterlegazpi
Guest

Latency increases over a period of time Feb 10, 2010 7:31:24 GMT

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Post by keymasterlegazpi on Feb 10, 2010 7:31:24 GMT

Here's my setup:

Fujitsu Amilo M3438G + Edirol UA1-EX Usb Soundcard + Samson C03u Usb condenser microphone + Cakewalk Sonar 8

In order to allow realtime monitoring of microphone inside Sonar I can get very low latency at buffer size sample of 128 or even at 64 instead of the default 512 in Asio4all 2.10 Beta 1.

However, after a period of 2 minutes or so, latency gradually increases over time until a noticeable delay is heard. I have to temporarily stop Audio processing within Sonar, and after re-enabling latency goes back to minimal. After a certain time, latency again increases.

What is causing this? Is there a solution?

Many thanks and keep up the good work!

Ian Green
New Member

Posts: 8

Latency increases over a period of time Mar 13, 2010 11:09:36 GMT

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Post by Ian Green on Mar 13, 2010 11:09:36 GMT

Some sound cards have a single native sampling rate, say 48000 or multiples, and internally resample audio at other rates (44100 for example) to the native rate. If the input and output resampling is not exactly symmetric, the output sample rate (44100->48000->44100) can be very slightly different from the input rate, leading to a drift in latency. With a sound card I have here, I can see the 44100 latency drifting by about 40 microseconds per second. But at 48000, it's rock solid.

If that is your problem, the best solution is to change your sampling rate to match the native rate of the card. If you can't do that, try checking the "Always resample" option in ASIO4ALL.

exyll
Junior Member

Posts: 74

Latency increases over a period of time May 26, 2010 21:26:51 GMT

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Post by exyll on May 26, 2010 21:26:51 GMT

I have the same problemen and I have the same USB mic.

It turns out then when I do not set it too low that the latency seems not to increase much. I usually set the latency somewhere between 192 and 256 samples. Also, make sure that you DO NOT CHECK hardware buffer on the mic as that also seems to not work very well for the latency.

I have set the input sample rate to 48kHz as I can clearly hear the difference between 44.1kHz and 48kHz. Seems that 48kHz s the native sampling frequency for the mic.

It can also be a problem with your DAW. I sometimes use Cantabile and I really have much less latency issues with it then any DAW.

Last Edit: May 26, 2010 21:28:56 GMT by exyll