KXStudio - All music is out of pitch!?

[Quillz]

Hi folks,

Wasn't sure where to put this as it's a bit odd - But I'm guessing it's more of a tuning and configuration thing than anything else.

Last night I was jamming away with my guitar (going through my amp and cab, and not through my comp) to some chord progressions I have, laid down in Ardour, all running in KXStudio 14.04. I do this nearly every night with no issues. When I finished I just shut everything down, like normal, and went to bed.

Today, I booted up, loaded up a tune in ardour and everything sounds faster and all my tunes are about 1 1/2 semitones higher than they should be. I double checked the tuning on my guitar - all in tune. No settings seem to have been changed in Cadence.

Odd.

I loaded up youtube in Firefox and found a backing track. Same thing. Booted up into windows, found the same track in youtube and there's no issue - guitar and track are all in tune.

This has me a bit baffled - not hard, to be fair, but...

Does anybody have any idea what might have happened?

Any help would be greatly appreciated.
Thanks.

[sysrqer]

Probably a sample rate mismatch, did you change any settings in jack?

[Quillz]

Thanks for the reply.

I had originally thought that and part of the bafflement was that it seemed like a sample rate issue but according to Cadence (in the Jack status section) sample rate was still 44100, which is what it's always been set at.

However, given your reply I had a thunk and remembered the setting in Envy24 Control Utility->Hardware settings - Master Clock. It was set to 48000. Not sure how, as I had to stop Jack before it would allow me to change it back to 44100.

Bit of a mystery that.

Anyway, problem fixed. Thanks.

[merlyn]

About 1+1/2 semitones is right. It's 147 cents.

To work that out you use

cents = 1200 * log2(x2/x1)

where log2 is log to the base 2

In this case cents = 1200 * log2(48000/44100) = 146.70600061

Calculators usually don't have a log2 button, so you use

logA(x) = logB(x)/logB(A)

Using the log10 button on a calculator this would be

log2(x) = log10(x)/log10(2)

To get your head around this : log2 tells us how many octaves there are in a ratio, and there are 1200 cents in an octave so we multiply by 1200.