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#1 2015-06-17 09:07:32

sprince
Member
Registered: 2015-06-17

0.7.0 Crackling on Mac Pro with audio interface / OS X 10.9.5

Hello There

I use a Mac Pro (early 2008 version), OS X 10.9.5 with Imitione 0.7.0, Logic Pro X, the Komplete Audio 6 interface and an Electro-Voice N/D767A microphone.

If I have my audio output set to the Komplete Audio 6 interface and have headphones etc connected via the interface's headphone socket then when I launch imitone all audio has a high amount of crackle - whether playing instruments via imitone & Logic, keyboard & Logic, online videos, iTunes etc.

As soon as I quit imitone the crackling stops.

If I have my audio output set to Internal Speakers/Headphones/Built-In Output and I use the inbuilt speaker/headphones connected via the Mac's own headphone output then launching imitone doesn't cause this problem.

Any suggestions? Has anybody else come across a similar problem when using an audio interface?

Thanks.

Last edited by sprince (2015-06-17 09:15:23)

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#2 2015-06-17 16:36:24

Evan
developer
From: Olympic Peninsula, WA
Registered: 2014-05-23
Website

Re: 0.7.0 Crackling on Mac Pro with audio interface / OS X 10.9.5

Essentially the problem is that two programs are accessing the same low-latency audio interface, causing problems in the timing of the sound.  You can think of the two programs as "fighting over" control of the audio clock.  This issue doesn't usually happen when one program is using a device's input while the other uses its output.  It is also much more likely to happen when the two programs are requesting different sample rates from the interface.

Different solutions might work depending on circumstance:


A -- Disable audio input to Logic Pro while using imitone.  (Likely to solve the problem, but you can't record from your microphone in logic.)

B -- Use different input devices for Logic Pro and imitone -- a USB cardioid microphone can work very well with imitone, for instance, or if you have a spare interface and microphone that will do nicely.  (Likely to solve the problem, but requires an extra interface.)

C -- Change Logic's input sample-rate, and see if there is some setting that makes the problem vanish.  (Less likely to solve the problem, but the most convenient solution if it works.)


Eventually, plugin versions of imitone and support for inter-application audio routing will offer additional ways to solve this problem.  I'll also be adding a sample rate setting to imitone next version, which should help with approach C.

Let me know if this helps.

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#3 2015-06-19 03:28:11

sprince
Member
Registered: 2015-06-17

Re: 0.7.0 Crackling on Mac Pro with audio interface / OS X 10.9.5

Curiously today and yesterday when I first turned the computer on there was very little crackling, although it seemed to get worse as the day went on but not as bad as it had been before - I hadn't changed any settings etc.

Disabling the audio input in Logic didn't solve the crackling problem, changing Logic's sample rate to various settings made the crackling particularly bad/invasive, which wouldn't go away by quitting and restarting Logic/imitone or changing the sample rate/reverting to the original rate - the computer needed restarting.

I don't really want to buy another microphone/USB microphone/interface but I have thought of a possible work around - I'll have one pair of headphones plugged into the audio interface and one into the Mac Pro itself and then switch the audio out appropriately when I'm using imitone with Logic.

That will mean that I don't have to keep plugging and unplugging headphones as using the Mac Pro's inbuilt audio seems to not cause the crackling/bypasses the audio interface. Not ideal but hopefully it will work.

I would be curious to know if this is likely to happen with more than just the Komplete Audio 6 interface or if it's connected to it in particular.

Thanks.

Last edited by sprince (2015-06-19 03:30:35)

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#4 2015-06-23 12:30:45

Evan
developer
From: Olympic Peninsula, WA
Registered: 2014-05-23
Website

Re: 0.7.0 Crackling on Mac Pro with audio interface / OS X 10.9.5

Hey, sprince --

So to clarify...

This configuration doesn't work:
Input to imitone from Komplete Audio 6 interface
No input to Logic
Output from Logic to Komplete Audio 6 interface

..But this one does:
Input to imitone from Komplete Audio 6 interface
No input to Logic
Output from Logic to built-in headphone jack

Is that right?

The way the problem worsens as time goes on probably has to do with the audio clocks of two different devices falling out of sync over time.  This can happen when using different audio input and output from different sources in one program, or using a single device from two programs.  Most of the time (but not always) using a device's input in one program and its output in another isn't a problem -- but it doesn't sound like that's the case here.

Unfortunately this is an OS-level problem and the best I could do about it in imitone is to detect that the audio is garbled, or provide the plugin versions as mentioned.

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#5 2015-06-26 04:17:53

sprince
Member
Registered: 2015-06-17

Re: 0.7.0 Crackling on Mac Pro with audio interface / OS X 10.9.5

Hello Evan/all

Yes, that's right re the setup and crackling.

As I say, I'm curious to know if anybody else has had this problem with other audio interfaces - I can't see any mention of it in the forums so it may be some curious mixture of my setup/settings/my version of OS X/Logic Pro X/Komplete Audio 6 interface/imitone.

My setup in those re audio is fairly standard - as far as I know I haven't made any particularly obscure changes to settings.

Anyway, thanks for the help. Let me/the forum know if there's likely to be any additions to imitone that will resolve it.

Thanks.

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#6 2015-06-29 11:04:06

Evan
developer
From: Olympic Peninsula, WA
Registered: 2014-05-23
Website

Re: 0.7.0 Crackling on Mac Pro with audio interface / OS X 10.9.5

sprince --

The features that would be most helpful with this will be the plugin version (planned), support for inter-application audio (tentative) and the sample-rate option (planned) as mentioned earlier.

It's a shame that you can't use input from the device from one app and output to it from another.  As far as I know, most hardware supports that -- for instance, I have an imitone/Logic setup with a PreSonus FireStudio which is very reliable as long as I don't push CPU usage past about 60% from either application.  (If I do, it begins to crackle and doesn't stop until the interface is restarted.)

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#7 2016-02-26 11:56:56

Flosstradamus
Member
Registered: 2016-02-26

Re: 0.7.0 Crackling on Mac Pro with audio interface / OS X 10.9.5

Sadly I am experiencing the same thing. Ive tried the options above, downloaded soundflower, Even installed Antipop (http://www.macupdate.com/app/mac/29024/antipop). Still heavy crackling through imitone causing porly registered notes. Anyone else have solutions??

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#8 2016-02-27 19:48:39

buckfumbler
Member
Registered: 2016-02-27

Re: 0.7.0 Crackling on Mac Pro with audio interface / OS X 10.9.5

Encountering the same problem. Crackling and a thousand notes where one should be. it seemed to get worse when i upgraded 0.8.1 It has trouble with low notes and doesn't sustain a note with the high pitches.

Screen_Shot_2016-02-27_at_7.40.47_PM.png

Running a Mac mini OS X 10.10.5
1.4ghz Intel Core i5
4GB ram
Presonus AudioBox USB interface
Garage Band, Studio One 3, and Pro Tools First 12.3.1

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#9 2016-02-27 20:10:34

Flosstradamus
Member
Registered: 2016-02-26

Re: 0.7.0 Crackling on Mac Pro with audio interface / OS X 10.9.5

Ok I figured it out for the time being.

If you change your sample rate of your soundcard in audio to midi setup to anything above 88,200 Hz it will fix the crackle.

Last edited by Flosstradamus (2016-02-27 20:16:45)

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#10 2016-02-28 13:48:49

buckfumbler
Member
Registered: 2016-02-27

Re: 0.7.0 Crackling on Mac Pro with audio interface / OS X 10.9.5

i'm unable to change the sample rate. It doesn't give me the option.

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#11 2016-03-02 18:40:00

buckfumbler
Member
Registered: 2016-02-27

Re: 0.7.0 Crackling on Mac Pro with audio interface / OS X 10.9.5

no other options or opinions?

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#12 2016-03-04 11:38:01

Evan
developer
From: Olympic Peninsula, WA
Registered: 2014-05-23
Website

Re: 0.7.0 Crackling on Mac Pro with audio interface / OS X 10.9.5

Hey, Buck --

Crackle is most often a synchronization problem, and has one of two causes:

  1. imitone is using more CPU power than is available (not the case for you)

  2. Two programs are using the same audio device with different settings.

It's almost certainly #2 for you.  The easy work-around is to use a different microphone for imitone, or to disable recording in your DAW (Logic/GarageBand).  The trickier one is to make sure they're using the same sample-rate and buffersize settings.  imitone usually requests a 256-sample buffer on Mac -- try setting that size in your DAW and experimenting with different sample-rates there.

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#13 2016-03-06 18:23:48

buckfumbler
Member
Registered: 2016-02-27

Re: 0.7.0 Crackling on Mac Pro with audio interface / OS X 10.9.5

Is it possible to make imitone automatically adjust its sample size to the active DAW?

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#14 2016-03-09 11:57:58

Evan
developer
From: Olympic Peninsula, WA
Registered: 2014-05-23
Website

Re: 0.7.0 Crackling on Mac Pro with audio interface / OS X 10.9.5

Hey, Buck --

Astute question -- I will be looking into that in the future.  It's possible, but difficult -- I need to find a way for my program to detect the corruption in the audio and take that as a cue to try different settings until something works.

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