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iunspoken

macrumors newbie
Original poster
Nov 14, 2007
10
1
Singapore
Hi everyone,

Have a weird problem. I've also found multiple forum and discussion threads on this issue dating back to 2010.

Without any apparent reason or trigger point, the volume on my Mid-2010 Mac Pro started fluctuating on it's own.
There is no observable factor that affects or triggers the volume fluctuation.
I've tried deleting the iTunes plist files, done a PRAM reset, even a complete power cycle including my UPS. But nothing seems to be able to resolve it.
It's become extremely frustrating as my creative work revolves around having to edit audio as well.

Any one has come up with a viable solution these past 5 years?


Mid-2010 Mac Pro
Mac OS 10.5.5
256GB SSD
64GB RAM
Audio Output: Line Out
 

iunspoken

macrumors newbie
Original poster
Nov 14, 2007
10
1
Singapore
Any more details, or examples? What do you mean by volume fluctuating?

Meaning at any given point in time, the system volume will fluctuate on it's own. Going low, then back to normal.
I do edit work on Premiere Pro CC, so you can see how this can really screw things up.
 

VAGDesign

macrumors 6502
Feb 1, 2014
344
189
Greece
Might seem crazy but, is your keyboard keys OK? (I mean without dust or dirt on the volume buttons)
If you have an Apple Display (I think some have volume controls on it) is it OK?
Any other device that might control your volume, is it functional and working OK?

Just some thoughts...
 

h9826790

macrumors P6
Apr 3, 2014
16,656
8,587
Hong Kong
Is the HUD shows anything on the display when the volume change? If the system volume hasn't change (e.g. stay at 50%), but you can clearly hear that the volume is fluctuating. May be it's the cable's / speaker's problem.
 

iunspoken

macrumors newbie
Original poster
Nov 14, 2007
10
1
Singapore
Nope. none of those factors that were suggested were conclusive.
the HUD doesn't come up when it happens. Definitely not the volume keys either, almost 100% certain of it.
Thought it might be a speaker issue, so went through the cables, power supply and even an alternate audio source, not a problem there.

the volume keys still respond accordingly, just that the unpredictable volume changes messes around with the eventual output.
 

h9826790

macrumors P6
Apr 3, 2014
16,656
8,587
Hong Kong
Do you have another boot drive? Backup OSX or Windows? If yes, try that and see if still the same, that may be helpful to focus on software / hardware.
 

ixxx69

macrumors 65816
Jul 31, 2009
1,299
883
United States
Thought it might be a speaker issue, so went through the cables, power supply and even an alternate audio source, not a problem there.
You're absolutely sure? Because I was having a similar issue with a pair of powered speakers on my old 2010 cMP, and a new pair of powered speakers fixed the problem for me.

The issue was kind of subtle - it didn't go from 10 to 1, it was more like 7 to 4 and then back to 7 like it was temporarily dropping out.

If that's definitely not the issue, one long shot thing to investigate is if you have an automatically gain-adjusting microphone - maybe it's somehow affecting the line out as well.

Good luck with that one!
 

iunspoken

macrumors newbie
Original poster
Nov 14, 2007
10
1
Singapore
That's what the Apple Support Staff said too. Eventually I either had to lug my entire Mac Pro down to a AASP, or try a full restore.
Accordingly to him, there have been random reports of this problems, but not enough to make it an official issue. Reports date back all the way to OS 10.2. There has never been an official fix or solution though. So.

@ixxx69 yeah that pretty much describes my problem actually. it's like a 6 to 3 then back up to 6, sometimes a 1. I'm not completely convinced it's a power speaker problem though. The speaker works fine on my iPhone.
 
Jul 4, 2015
4,487
2,551
Paris
'Loudness' level changes depending on the source of the sound. Different videos and audio files have their own loudness levels independent of system volume.
 

iunspoken

macrumors newbie
Original poster
Nov 14, 2007
10
1
Singapore
'Loudness' level changes depending on the source of the sound. Different videos and audio files have their own loudness levels independent of system volume.

thanks. i would know that cos i edit for a living. this level changes has nothing to do with source files, audio or video, loudness or peak levels. as it is, for now i'm editing audio based on level readouts instead of the actual audio that i'm hearing. it's frustrating but doesn't seem like i have a choice as of now.
 
Jul 4, 2015
4,487
2,551
Paris
thanks. i would know that cos i edit for a living. this level changes has nothing to do with source files, audio or video, loudness or peak levels. as it is, for now i'm editing audio based on level readouts instead of the actual audio that i'm hearing. it's frustrating but doesn't seem like i have a choice as of now.
I'm with you. There has been something about the OSX audio driver. In Windows on the same computer it doesn't happen.
 

Arron Rouse

macrumors regular
Apr 28, 2010
105
32
Chichester, UK
thanks. i would know that cos i edit for a living. this level changes has nothing to do with source files, audio or video, loudness or peak levels. as it is, for now i'm editing audio based on level readouts instead of the actual audio that i'm hearing. it's frustrating but doesn't seem like i have a choice as of now.

Maybe ditch the speakers and try a pair of headphones before lugging your kit down to the service centre?
 
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iunspoken

macrumors newbie
Original poster
Nov 14, 2007
10
1
Singapore
Read the negative reviews at Amazon.com for that particular speaker system and I think you'll find your answer.
i'm not 100% convinced that it's due to the speaker system itself really. cos with an iphone input, it works just fine. it has worked fine for the past year plus, until i upgraded to Yosemite, but even then, the problem only came in 2-3 weeks after i upgraded.
 

iunspoken

macrumors newbie
Original poster
Nov 14, 2007
10
1
Singapore
You should still try with some other set of speakers. If you don't then your troubleshooting is poor.
didn't say i didn't. tried with headphones, an identical pair of speakers, and a whole different set of speakers as well.
same problem.
 

Inutopia

macrumors 6502
Apr 8, 2009
299
84
South of Heaven
didn't say i didn't. tried with headphones, an identical pair of speakers, and a whole different set of speakers as well.
same problem.

You also never said you did, and I'm not the first person to suggest it with you not mentioning you had already tried this. Good luck with your issue, I'm out.
 
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