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weird "chirps" in renderings

Posted: Mon Mar 29, 2010 6:14 pm
by quandry
Hey, I'm on Live 8 (and every previos version since 2) on an XP pro pc laptop, RME multiface I soundcard. I record a lot of live instruments, and generally am keeping the buffer size at like 128 samples, about 7 ms in/out of Live. I get some occasionally glitching during playback when I have a lot of tracks, but usually not too bad. However, since at least live 6, and 7, and now 8, I occasionally, but regularly, get weird digital-sounding "chirps" in audio renders/exports.

These are not related to clipping (no clipping the master here!), and they are not predictable/repeatable--they'll show up in weird places a few times a minute, but if I render again it won't be identical in terms of where/if these chirp sounds show up in the exported audio. Any thoughts--I thought the process of off-line audio exporting should eliminate stuff like this from happening?!? Please help!!! Should I test out upping my buffer size on the RME? Is it possibly some wierd background shit happening on my pc (my C: drive is pretty jammed up and not very de-fragged)? All my audio files are on external drives...I can deal with some weirdness during playback, but my renderings really need to be flawless...thanks in advance, really could use some advice here.

Re: weird "chirps" in renderings

Posted: Mon Mar 29, 2010 9:44 pm
by quandry
anyone? Could it be vst weirdness--got a few vsti synths and samplers in there, or maybe it's my drums? I'm using BFD2's killer drum library and vsti inside of Ableton for beats, streaming the BFD2 samples from an external USB drive--could it be tripping up on pulling the samples off the external drive fast enough while rendering/exporting audio? Just thinking out loud here--it seems like it may have started happening to me around the same time I started using BFD2, but I can't be sure.

Has no one else had wierd "chirp"/bird-like little digital-sounding anomolies end up on your exported audio?

Re: weird "chirps" in renderings

Posted: Mon Mar 29, 2010 11:47 pm
by ibdk
Did you try increasing the buffer a notch?

Re: weird "chirps" in renderings

Posted: Tue Mar 30, 2010 12:04 am
by quandry
gonna try tonight with some more methodical testing, will report back and maybe drop a few sound samples of the issue on my website for ppl to hear., thanks.

Re: weird "chirps" in renderings

Posted: Tue Mar 30, 2010 12:11 am
by leedsquietman
increasing latency when you're mixing down in the studio is always a good idea.

Low latency for tracking (and any real time automation)- medium to higher latency for final mixdowns is fine and preferable for smoother processing.

Seriously, why strain your system when your loading on plugins after having done the tracking - whack it up to 512 or 1,024 samples (or up to 2,048 if a real heavy project with lots of plugins) and your system will thank you for it. GLitches, pops, chirps, crackles - all largely caused by CPU strain caused by using too low a latency buffer.

There could be other explanations, but this is where I would start.

Re: weird "chirps" in renderings

Posted: Tue Mar 30, 2010 12:21 am
by quandry
leedsquietman wrote:increasing latency when you're mixing down in the studio is always a good idea.

Low latency for tracking (and any real time automation)- medium to higher latency for final mixdowns is fine and preferable for smoother processing.

Seriously, why strain your system when your loading on plugins after having done the tracking - whack it up to 512 or 1,024 samples (or up to 2,048 if a real heavy project with lots of plugins) and your system will thank you for it. GLitches, pops, chirps, crackles - all largely caused by CPU strain caused by using too low a latency buffer.

There could be other explanations, but this is where I would start.
Cool, that sounds like sound advice....for some reason I had it in my head that because rendering is an off-line process, that the buffer size is somewhat taken out of the equation, but maybe not so...I actually usually end up around 1024 when doing heavy mixdowns with tons of effects--this might go a long way in explaining why it's usually my quick renders at 2 am, when I just finished tracking and am at 128 samples, that I usually get the chirpiness going on....I'll follow up after testing tmrw, but I think is clearly the place to start...thanks!

Re: weird "chirps" in renderings

Posted: Tue Mar 30, 2010 5:44 am
by Kearley
quandry wrote:Cool, that sounds like sound advice....for some reason I had it in my head that because rendering is an off-line process, that the buffer size is somewhat taken out of the equation, but maybe not so...I actually usually end up around 1024 when doing heavy mixdowns with tons of effects--this might go a long way in explaining why it's usually my quick renders at 2 am, when I just finished tracking and am at 128 samples, that I usually get the chirpiness going on....I'll follow up after testing tmrw, but I think is clearly the place to start...thanks!
I always thought this too. Maybe it's not the case.

Are these chirps a regular thing? ...or random? (sorry, did you post a clip somewhere?)
...have you thought of maybe a demo plugin that's expired and making those noises?