Static/distortion on recording in Yosemite

cmac185 · Post by **cmac185** » Wed Apr 22, 2015 6:14 pm

Thanks. None of these are in the suspect range, so I'd guess it could be the OSX version?

I guess that is good. IMHO, it has to be the OS since Audacity worked fine for me on Mavericks. If I had known when Yosemite came out what I do now I probably wouldn't have upgraded. In my mind it could be problems in Yosemite itself and how it handles the sound card or a subtle interface change that affects the reliability of how Audacity gets it's data. How to determine which it is is beyond me.

Are you familiar with the Terminal?

It depends on what you mean by familiar. I am comfortable using it, but have very little Bash knowledge or experience. I have figured out how to do what I need to do in Terminal, but not much more than that. If you have suggestions as to something I could try I would be willing to give it a go provided you give full instructions.

Cliff

cyrano · Post by **cyrano** » Wed Apr 22, 2015 8:57 pm

Hey, you know what bash is!

That definitely counts as "experience" in my book!

Four commands to disable background stuff:

Code: Select all

sudo chmod 0444 /System/Library/CoreServices/Dock.app/Contents/XPCServices/com.apple.dock.extra.xpc
sudo chmod 0444 /Applications/iTunes.app/Contents/MacOS/iTunesHelper.app                           
sudo chmod 0444 /System/Library/PrivateFrameworks/BookKit.framework/XPCServices/com.apple.BKAgentService.x
sudo chmod 0444 /System/Library/com.apple.sharingd.plist

Try one by one. After the command, restart the Mac and test audio.

I know, things that are intermittent might take months to test this way. And I haven't tested this on Yosemite, but it has solved phantom fans running and some audio weirdness for me. This is a continuous test for me too.

If it does nothing, revert to 0777 for the plist, restart and you're back in business.

There is a fifth, but I'm still trying to figure out what "pacemaker" really does. It shouldn't interfere with audio, but so should the others.

I also have no idea about impact on connected iphones, icloud or other "sharing" services. I don't use those.

cmac185 · Post by **cmac185** » Wed Apr 22, 2015 9:21 pm

I'll give them a try.

If you have read the past history on this problem, you know that another one of the very puzzling aspects to this is that Audacity is 100% reliable at home. It is only when doing the live recording that the problem crops up. Just as I was writing this it dawned on me that one difference between at home and at church doing the recording is that at home the Internet is active and not active at church. It would be really crazy if not having Internet is causing the issue, naw, it couldn't be that could it? Nothing else make sense, might as well try that one too.

Cliff

Post by **Gale Andrews** » Wed Apr 22, 2015 10:15 pm

Rather than experimenting with Audio to buffer I would set it as low as you can on the Yosemite machine and leave it there. You have the insurance of recording in parallel to the other machine.

And I would power cycle the mic between recordings, if I recall correctly that the other machine is not on Yosemite.

Gale

cmac185 · Post by **cmac185** » Thu Apr 23, 2015 12:02 am

Rather than experimenting with Audio to buffer I would set it as low as you can on the Yosemite machine and leave it there. You have the insurance of recording in parallel to the other machine.

That would be about 15. Anything is worth a try at this point.

And I would power cycle the mic between recordings,

Are you referring to the receiver only or both the receiver and mic? Just wondering what you're thinking might be changed by the recycle.

if I recall correctly that the other machine is not on Yosemite

Correct, the other machine will be either on Snow Leopard or Mavericks.

Cliff

Post by **Gale Andrews** » Thu Apr 23, 2015 1:14 am

cmac185 wrote:
And I would power cycle the mic between recordings,
Are you referring to the receiver only or both the receiver and mic? Just wondering what you're thinking might be changed by the recycle.

If you can power cycle both, do so, but try the mic first. I''m thinking build up of interference after a while or anything Yosemite does not like with some device running continually without being re-initialised.

Gale

cmac185 · Post by **cmac185** » Thu Apr 23, 2015 1:43 am

Re: Static/distortion on recording in Yosemite

Permanent link to this post (unread) Posted by Gale Andrews » Wed Apr 22, 2015 7:14 pm

cmac185 wrote:

And I would power cycle the mic between recordings,

Are you referring to the receiver only or both the receiver and mic? Just wondering what you're thinking might be changed by the recycle.

If you can power cycle both, do so, but try the mic first. I''m thinking build up of interference after a while or anything Yosemite does not like with some device running continually without being re-initialised.

Pardon my skepticism, but with an analog device how would anything build up that wouldn't be heard on the parallel machine? Since the parallel recording is fine I'm not too hopeful this will help, but I'm willing to try anything at this point. Would just unpluging the line-in line and reinserting it accomplish the "reset"?

Cliff

Post by **Gale Andrews** » Thu Apr 23, 2015 12:44 pm

cmac185 wrote:

Re: Static/distortion on recording in Yosemite

Permanent link to this post (unread) Posted by Gale Andrews » Wed Apr 22, 2015 7:14 pm

cmac185 wrote:

And I would power cycle the mic between recordings,

Are you referring to the receiver only or both the receiver and mic? Just wondering what you're thinking might be changed by the recycle.

If you can power cycle both, do so, but try the mic first. I''m thinking build up of interference after a while or anything Yosemite does not like with some device running continually without being re-initialised.
Pardon my skepticism, but with an analog device how would anything build up that wouldn't be heard on the parallel machine? Since the parallel recording is fine I'm not too hopeful this will help, but I'm willing to try anything at this point. Would just unpluging the line-in line and reinserting it accomplish the "reset"?

The other machines are "other machines" and other versions of Mac.

If the receiver connects to a power supply, you could unplug it. But I'm thinking more of the mic.

Gale

cmac185 · Post by **cmac185** » Sun Apr 26, 2015 10:21 pm

Well here we are again. I decided to try to establish a base line from which to experiment. The following is what I did and I got 2 good recordings. First time ever on Yosemite!

1. Turn off WiFi.
2. Set App Nap off for Audacity.
3. Reboot at church. Only 3 small programs open and minimized. Programs that do not access Internet.
4. Open Audacity and set buffer size to 20.
5. Quit Audacity - Cmd+Q.
6. Restart Audacity
7. Do first recording and save recording.
8. Change Buffer size to 15.
9. Quit Audacity
10. Restart Audacity. (no wait period between quit and restart.)
11. Do second recording and save recording.
12. Quit Audacity.

End result is two good recordings. It's only been 3 months or so in coming.

Now to hopefully create a test case that will give a bad recording with the old settings and then one by one try to identify the culprit. Hopefully there's only one.

Cliff

Post by **Gale Andrews** » Sun Apr 26, 2015 10:53 pm

I'm glad it's working for you.

The first step I would omit is #8 (change buffer to 15). I would still doubt refreshing/tweaking an already low buffer setting would make any difference.

Gale