Tuning sample introduces clicks

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Joined: Sat Feb 12, 2011 10:05 am

Tuning sample introduces clicks

Postby dswo » Sun Jun 10, 2012 1:04 pm

Yesterday I downloaded a sample of the Moog Taurus from freesound.org. I soft-looped it in Hokusai, then pasted it into ThumbJam. The sample was labeled C2, but after I finished with the instrument, I noticed that it was out of tune. I could tune it up in the sample editor, but after I did, there were noticeable clicks when I played a sustained note. These clicks weren't there before the tuning, but after the tuning I couldn't get rid of them, even if I reset the tuning to 0.

Any ideas for fixing this? One solution would be to tune the sample outside of TJ, but if there's something in TJ that I don't understand properly, I'd rather learn how to make it work in the app.

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If the looping that you did

Postby Jesse » Sun Jun 10, 2012 3:58 pm

If the looping that you did in Hokusai wrote out a WAV file with the loop points embedded in the metadata, there is a known subtle issue with the way TJ treats the loop end point. Kind of a long story, but I recently discovered that the software I use to create the instrument samples (keymap pro) actually write out the loop end point one sample earlier than the desired, due to ambiguities of the specification (that half of all software tends to get correct). Thumbjam thus interprets it the "nonstandard" way, as an unintended consequence.

So, if right before you export the sample in your editor you set the end loop point one sample later, then TJ should get it right. Please post your edited sample here or email it me at support@thumbjam.com, just in case.

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Thanks for the off-forum file

Postby Jesse » Sun Jun 10, 2012 11:02 pm

Thanks for the off-forum file email. Since you had a full-sample loop, my comments above are irrelevant (but maybe not to some future issue someone has). However, I figured out the problem... apparently when you make any changes in the Edit Sample page, it decides to set a crossfade amount for the sample when it is looping, and the implementation for the built-in loop crossfading is broken, which causes the clicks. When you first add the sample and turn the loop on, the xfade parameter remains at 0, and it loops the full sample correctly... after changing any other value on that page, it won't. You can't edit this parameter in the app, it has to be done in the instrument metadata after exporting.

The workaround is annoying, but possible. Once you get it where you want it in terms of everything else, you need to export your new instrument to your computer to make a minor edit in a text editor. Wifi transfer, in the recorded instruments section further down the left column, you click Archive, then you can Download it. Unpack the zip file on your computer and edit the new.flot file with a text editor. Look for the xfade_samples="2048" (or similar value) parameter inside a element and change the value to "0". Then re-zip the contents of the folder up, and upload it as an instrument in wifi-transfer, which should overwrite the existing one.

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Certainly, I'll fix the issue

Postby Jesse » Tue Aug 28, 2012 12:04 pm

Certainly, I'll fix the issue for the next release... it's just that I can't promise when that will be.

As for another iPad app to do loop editing on audio files..... I haven't come across one myself, but I haven't done enough research. Ideally, you'd be able to do what you need in TJ itself, but of course that hasn't been implemented yet either.

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Ugh, it appears that this fix

Postby Jesse » Thu Mar 14, 2013 11:35 pm

Ugh, it appears that this fix fell off my radar last year. Putting it back on the list, sorry!

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