Re: [linux-audio-user] Re: The famous "Jack Hum" (Can't record and desparate)

From: Daniel Wagner <wagi@email-addr-hidden>
Date: Sat Nov 11 2006 - 14:51:04 EET

> But the most intriguing part of the whole story: Not only did the noise
> get louder at a lower latency, it also seemed to precisely double its
> frequency when running at halve the number of frames. I even tried to
> measure the frequency of the noise. As far as I remember, when running
> jack for instance at 44100Hz, periodsize 32, the noise was at exactly
> 44100/32 = 1378Hz!

Is an interrupt fired at each period? If so the cpu will use more power
(or woken if it was asleep); a small power 'surge' which can of course
have an influence on any analog hardware near by.

daniel
Received on Mon Nov 13 04:15:12 2006

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