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Gear / Technical Help => Ask The Tapers => Topic started by: divamum on December 02, 2006, 09:25:49 PM

Title: Test recording came out like the Chipmunks on steroids...
Post by: divamum on December 02, 2006, 09:25:49 PM
Okey dokes...

So, I updated the Rockbox on my iRiver h120 to a version which includes digi in. Mics and pre are talking, there's a signal, batteries etc.  However, just ran a test recording during a rehearsal and it came out like the freaking chipmunks!! It's obviously running "fast" but I thought my settings were right - anybody wanna clue me in as to what's going on here?    Did I screw up a sample rate or something (presumably it should be 44.1, and if so where do I change that in RB - I can't find a selection  other than one where it tells me it's "same as source" and the source was the mic2496 set at 44.1)

Sorry if this is a really dumb n00b question but this is my first excursion into the optical dark side - be gentle with me!! ;)

TIA!

Edited to add: I now can't get it to repeat the fault. Just ran everything again and it was fine.   ???
Title: Re: Test recording came out like the Chipmunks on steroids...
Post by: Brian Skalinder on December 02, 2006, 11:37:26 PM
Sounds like a mismatch between the WAV header's sample rate (a simple descriptor of the file) and the actual sample rate of the data itself.  Easy to fix by opening the file in one of the popular WAV editors and changing the file's sample rate (which ultimately just adjusts the header).  Note:  this is very different from converting the sample rate, which is a lengthy process.  What s/w editor do you have?  Someone can probably walk you through it for future reference.

As to why it happened, and you haven't been able to repeat it, I can't really explain.  But it seems to happen with some of the new consumer recorders from time to time.  I wouldn't try too hard to nail down the root cause, as I think it will prove exceedingly difficult and time consuming, if at all possible.
Title: Re: Test recording came out like the Chipmunks on steroids...
Post by: divamum on December 03, 2006, 09:05:51 AM
Thanks Brian.  In fact, I kind of stumbled over the fact that I could "fix" it in Wavelab by accident:  I was trying to extract a little clip to post here as an example so I copied and pasted the snippet into a new document in Wavelab - WL prompted me that "the sample rate in the destination was not the same as the clip" so I tried letting it change it just to see what happened and it of course came back down to normal pitch.    But I had no idea WHY this had worked, so many thanks for taking the time to explain!  Much appreciated.

My main concern with wanting to know the why's and wherefore's is to avoid repeating it - so far so good but, as always with new gear, there's a steep  learning curve!

Tx again.
Title: Re: Test recording came out like the Chipmunks on steroids...
Post by: Gedit on December 03, 2006, 06:40:45 PM
FYI .. similar symptom, different reason ... I ran into this once with a laptop that had its sound card driver corrupted. The wav file saved at a different sample rate than it had been recorded at and ended up sounding like Alvin on Steroids. A re-install of the laptop sound card driver fixed the issue, but the recording in this case was lost.

Title: Re: Test recording came out like the Chipmunks on steroids...
Post by: divamum on December 15, 2006, 09:44:54 AM
Well, I figured out how it happened, cuz I reproduced it (I caught it this time, at least).  So, in case somebody else evern needs to know:

It appears to reset sampling rates if the optical cable is unplugged while the iRiver is switched on in standby and/or if you try to press "record" before you have plugged in the cable (it seems that if the source is selected as digital, the unit won't start recording UNTIL the cable is seated in position).  The soluution is a simple reboot, then plug in BEFORE going to record. 

FWIW.