"theft" of audio output by Audacity on Mac

[wildsage2]

I know that in the past there was a chance that Audacity would "steal" the internal Mac audio output settings, making Audacity the only program that would play music. Nothing from ITunes or VLC or anything. In the stable version of Audacity this could be prevented by checking a box to avoid that problem. This box is not present in the unstable releases. (I bit the bullet and downloaded 1.3.5.) I had 1.3.3 and experienced this theft, I think (?) in changing the Mac inputs in Audio/Midi set-up to agree with 32 bit float, Audacity's default for recording. Was that even the proper or necessary thing to do? I had not changed output in any way. Not knowing how to restore Mac internal functions (although of course I set the Audio/Midi input back to its default), I had to resort to putting things back to normal via a Time Machine backup.

When and why does this event occur, and has it been prevented from happening in 1.3.5? Or what should I do to avoid it myself? Sorry for what may be a rudimentary question, but the experience I described above (and which I have also read about various Audacity sites) was frustrating, particularly because I didn't really know for sure why it happened or an easier way to restore Mac's proper output.

My current method of "avoidance" has been merely to use 16 bit input from Audacity which, of course, corresponds to the Mac default input set up. Suggestions would be much appreciated as I realize that 32 bit float would be a preferable method for recording.

Many thanks,
Christopher

[kozikowski]

<<<I know that in the past there was a chance that Audacity would "steal" the internal Mac audio output settings>>>

First I heard of this. Audacity is a complete slave to the operating system audio settings and most people have trouble the other way 'round. I can't get audio into Audacity because Mac preferences are set incorrectly--but everything else works. Audacity appears just like QuickTime Pro. If you can record and play audio in QuickTime Pro, you should be able to record and play audio in Audacity.

In that whole page, you never once said what you are trying to accomplish. What's your goal?

Koz

[steve]

I've never heard of this problem either.
It may be useful to know what kind of Mac this is.
[EDIT] Looks like it is an Intel Mac with OS X 10.5.3.

but the experience I described above (and which I have also read about various Audacity sites)

Could you post some links - perhaps it is the way that you are describing the problem that we do not correctly understand.

[Gale Andrews]

I've never heard of this problem either.
It may be useful to know what kind of Mac this is.
[EDIT] Looks like it is an Intel Mac with OS X 10.5.3.

This problem is quite well known and documented:
http://audacityteam.org/wiki/index.php? ... g_Audacity

The crux of it is that QuickTime and most Mac audio apps. are not clever enough to let one app. use say 24 bit 48000 Hz, and then change sound settings themselves back to standard 16 bit 44100 Hz when they have to play sound. Instead they just produce no sound until the user sets global sound settings back to what they want.

I'm not on Mac but I did not know of any intention to withdraw the "Do not modify audio device settings (such as sample rate)" checkbox, and we still mention it in the Beta readme, but this checkbox is certainly not in our current source code. I will see what I can find out.


Gale

[kozikowski]

Might this also account for the apparently much higher instability Macs seem to have with 24-bit audio?

Koz

[Leland]

Hi Christopher,

A couple of questions for ya...

1) How'd you change the default sample rate in Audio MIDI Setup to float32? Do you actually have a 32-bit float option?
2) What exactly do you mean by "theft"? Can you give a step-by-step of what made you believe Audacity was the culprit?

Mind you, I'm not saying that it wasn't the cause. I've just never had a problem with Audacity changing the system-wide settings in the 1.3.x series. (Most definitely had that problem with 1.2.x.) And, I need to get a better understanding of your issue before I can start to track it down.

Thanks,

Leland

[Gale Andrews]

Hi Leland

Not being on Mac, I've never *completely* understood the problem in 1.2.5/6. I believe if you asked Audacity to record say 16 bit 48000 Hz, and observed Audio MIDI Setup, you'd see it change to 48000 Hz and then other apps may not have sound. But given the Audacity default is 32 bit 44100 Hz, and Audio MIDI Setup (I thought) had no 32 bit option, I don't know what Audio MIDI changed to exactly that then meant 16 bit 44100 Hz apps had no sound.

But can you clarify with 1.3.5, if you set it to record 24 bit 48000 Hz, doesn't it now change Audio MIDI settings if you open that up and take a look (if not, are we sure Audacity really is recording 24 bit 48 000Hz)? Or does Audacity change the Audio MIDI Settings, but then change them back to default when it exits?

Thanks

Gale

[kozikowski]

<<<I believe if you asked Audacity to record say 16 bit 48000 Hz, and observed Audio MIDI Setup, you'd see it change to 48000 Hz and then other apps may not have sound.>>>

Given my video background, I do 48K/16 all the time on three different Macs and have never noticed all my audio applications stopping dead. I have never checked that "Do Not Modify Audio Settings" box and am spending a lot of time wondering what everybody's talking about.

I do notice, however, that the work "MIDI" is used a lot with this problem. I never use MIDI services (on a Mac). I will also bet this is an artifact of trying to record internet sound. Recording its own output is not something Macs do naturally and killing the output sound would be a natural result of getting it wrong.

Koz

[wildsage2]

Sorry for lack of clarity:
1. GaleAndrews is right that the problem is well documented (see that post above).
2. My goals: I am digitizing, and trying to improve the sound quality of very degraded and old audio cassettes of many of my own compositions and performances from my University Career. I am doing the same for another retired colleague. But I am "learning" on the job as I have no audio editing experience.
3. I never use any Midi settings or instruments, but on the Mac the Audio Input is controlled through the Audio Devices/Midi Devices System preferences panel, two sides of one coin.
4. No, you cannot choose 32 bit float on the Mac as an input source as it is not available. The available settings are 2ch-16 bit, 2ch-20 bit, and 2ch-24 bit.
5. The Stable versions of Audacity on Mac had a check box preventing Audacity from taking over System settings (as per GaleAndrews post). The unstable releases do not have this option on Mac.
6. My "theft" occurred using Audacity 1.3.3. I believe when I tried to choose an input other than 2ch-16 bit from amongst the three available, and matched it to the same in Audacity, in hopes of better editing potential. If I remember correctly it was 2ch-24 bit.
7. Simply resetting to the Mac default in the Audio Devices/Midi Devices System Preference and even rebooting did NOT return the system to normal. Audacity remained the only app that would play sound. Hence my resort to a Time Machine backup.
7. Although 32 bit float is the preferred setting for better quality control and the Audacity default, should I just stick with 2ch -16 bit input at 44,100 hz (Mac default) and set Audacity likewise, or are there work arounds?
Hope that is a little clearer. Thanks for everyone's contributions.
Christopher

[Leland]

Sorry for lack of clarity:
6. My "theft" occurred using Audacity 1.3.3. I believe when I tried to choose an input other than 2ch-16 bit from amongst the three available, and matched it to the same in Audacity, in hopes of better editing potential. If I remember correctly it was 2ch-24 bit.

Okay, I'll go grab a 1.3.3 and set to 2ch-24 to see if I can recreate. But, I have to say that I'm not very confident. I'll give it a good try, but I've just never seen the later 1.3.x series modify the system defaults.

7. Simply resetting to the Mac default in the Audio Devices/Midi Devices System Preference and even rebooting did NOT return the system to normal. Audacity remained the only app that would play sound. Hence my resort to a Time Machine backup.

This is the one that really interests me. Are you saying that when you went back into Audio MIDI Setup, you changed all of the settings back to default by manually changing the Source and Format for the your devices? Like this:

amsetup.png (62.1 KiB) Viewed 5222 times

And these settings didn't stick? When did they change back?

If they did stick after leaving Audio MIDI Setup, did you try an audio app like iTunes before starting up Audacity? If so, did it play? Did you just double click an audio file in Finder or did you load up iTunes (or whatever) and start playing it that way?

I know this is going to sound like a stupid question, but why did you feel you needed to restore? (Told ya...stupid question.)

The reason I'm asking is that I just can't figure out why your audio wouldn't play. I mean, if you changed the settings in AMS and then immediately turned around and double clicked a file in Finder and it didn't play, then there's most definitely something else wrong cause Audacity wouldn't have been able to get involved.

Now, if you are saying that when you double clicked a file in Finder and Audacity came up instead of your audio app of choice, then that's an entirely different issue and one that I could believe. (And one that I have a solution for.)

Finally, and this is probably the most important question, can you reproduce the problem?

Leland

(Sorry for all the questions.)