[LAU] a NEW question about pitch and speed

[Ken Restivo]

On Mon, May 31, 2010 at 09:24:21PM +0200, Igor Brkic wrote:
> On 31.05.2010 20:30, Kevin Cosgrove wrote:
>> Your reply IS helpful.  Now I know that someone else had the
>> issue.  While away from email for a bit, I wondered if maybe
>> the temperature of my system was high enough to cause a clock
>> rate to lower.  I can imagine that a badly designed system might
>> even allow a lower CPU speed to alter the audio clock rate too.
>> Your comment about the sound speed/pitch changing under high
>> load would be consistent with this theory, in that high load can
>> increase the system's internal temperature.
>>
>
> I don't know if temperature can cause a clock rate to lower, but that  
> explanation would certainly make sense. My old machine was (at that  
> time) five years old laptop which sometimes had problems with heating (I  
> was cleaning it from dust pretty often, but fan was almost always on).
>

Incorrect sample rate?

I've had this problem when having my jackd set to a different sample rate than, say, fluidsynth.

Perhaps your media player does not resample, or is getting confused based on what ALSA is reporting as a sample rate?

Are you using ALSA, or JACK, or Pulse, or what?

Also, do other players have this problem (i.e. mplayer, aplay, etc.) or just the one you normally use?

How much is the pitch off, exactly? If you have a guitar tuner, playing a sine wave and then placing the guitar tuner in front of the speakers might tell you how off exactly it is. If it's off by, say, the same ratio as 44.1/48, then there's your answer.

I really doubt it's any kind of hardware problem. Sounds to me like a sample rate glitch.

-ken