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OSX Playback Glitch in a Large Multitrack

Forum|Forum|7 years ago
October 7, 2018
2 replies
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Hi Guys,

I'm really new here, I hope this is an appropriate way to ask for assistance?

Using Audition CS6, I've programmed a multitrack audio file that is the backing track for a stage show I've got coming up atm, and I've just started rehearsing it with the band. It's a rather large multitrack.. it runs for 3 hours (the full show length), and the multitrack contains 15 different audio instruments, and each instrument is broken down into various clips.. the various clips all up probably total about 400 clips over the 3 hours.

Anyway, whilst all playing to it in rehearsal, it glitched the playback of all the tracks very noticeably and we were all suddenly out of time to the whole thing, even though we have a rock solid click track programmed into it all. The show starts in two weeks and this is something I've not encountered before. Is there a suggested settings setup I should have in place for Audition? I'm literally just running Audition on my Macbook Pro (running OSX 10.9.5) and just taking a stereo line out of the lineout jack (I know that's not ideal but it's unrelated to this glitch). Has anyone got any ideal tweaks I should make to Audition to reliably play back in a live situation?

Thanks Very Much,

Stu

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Correct answer ryclark

Thanks so much emmrecs.. Great tips indeed. The processor is a dual core i7 2.9ghz processor. I have a fast SD card slot on this Macbook Pro too.. Could I just put the whole project on a class 10 high speed SDHC card.. would that have the same effect as using an external USB3 drive for the project?

No harm in trying if you have one to hand. But I am not sure that an SDHC card would be as good as USB3 hard drive for streaming multiple audio files at once. Normally SD cards are used for one single high speed video stream. But on the other hand they are used in portable digital audio multitrack recorders.

R

romantic_Twinkle16B7Author

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Problem seems to be reliably sorted now everyone.. I moved it all to a class 10 sd card in my sd card slot and so far, so good! Thanks very much for your help. :-)

Stu

ryclark

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stum88023218 wrote
and just taking a stereo line out of the lineout jack (I know that's not ideal but it's unrelated to this glitch). Has anyone got any ideal tweaks I should make to Audition to reliably play back in a live situation?

But it might very well be related to audio playback glitches. First thing to check is that the sample rate of Audition's session and the Mac's soundcard are set the same. Having to sample rate convert the audio may very well cause clicks and glitches.

Secondly increase Audition's buffer size or latency in the Audio Hardware set up page. This allows more time for the audio to be processed on it's way out of Audition to the soundcard. Large latency can be a problem when recording but won't be for playback purposes. Do you have any added effects on your tracks?

One other thing where on your computer are the audio tracks being played back from? Are they on the same hard drive as the operating system? You need a pretty fast computer and hard drives for streaming fifteen audio streams simultaneously. Also you are running quite an old version of both Audition and the Mac OS.

R

romantic_Twinkle16B7Author

Participating Frequently

Thanks a lot Ry.. I really appreciate your advices. Sample rates both match, so that's good. As for increasing the buffer, it's currently set to 512 and can go in a few steps up to 8192. I never record anything, so this is literally just being used for playback at this point - what setting would be best for this, do you think? Can I go too high? Should I just stick it on say 1024 and no higher than that?

Regarding my Macbook Pro, yep, she's getting on a bit, but it's the fastest 2.9 core i7 upgraded processor Apple offered, before they moved to soldered on non-upgradeable units, so it's normally alright. It's maxed out with 16gb ram, plus a very fast spec ssd drive (which yes unfortunately, is where both the OS and the audio files are stored).

Looking forward to your thoughts on the buffer query?

Thanks so much,

Stu

E

emmrecs

Legend

(not ryclark, but just one or two thoughts which may help)

Since you are using your computer and AA for playback only, increasing the buffer size to its maximum, 8192, if needed, is not going to affect what you hear at all! Indeed, it should remove your glitches. The only caveat is that you might notice a slight delay in the tracks starting to be heard because the buffer will need to be filled first before actual playback can begin.

Your i7 2.9 GHz CPU, is it multicore or only single core? If the latter, that again could affect the playback throughput.

As ryclark indicated, it is always best policy to have the audio files on a separate HDD to the OS. Your SSD may be fast enough to allow the audio to stream successfully, but there is no telling when the OS might decide to "grab" the CPU in order to perform some action it considers vital at that moment. Such "grabbing" can affect the throughput of data, which, in your circumstances absolutely must be continuous, though the increased buffer will clearly help.

Are you able/willing to transfer your audio tracks to an external HDD? If your computer has at least one USB 3 slot available, I would, personally, stream the audio from a dedicated external USB 3 drive.

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