Page 1 of 2

Sound Problem!!

Posted: Sun Nov 04, 2012 7:30 pm
by JerryFreilich
OK folks, I've got another nasty one that's driving me nuts. Sounds like a job for SuperMan.

Last night I was watching a streaming Netflix video... playing the audio out through my MacBook Pro to my TV. As it happens, the machine shut down while the movie was playing and I had to start it up again, after which it seemed to function normally... the sound through the TV seemed normal. But...

Today I find that the output sound on my computer is greatly reduced... 50% or less volume than normal. The audio sliders in System Preference are at their max. Sound is reduced in ALL apps including iTunes, Safari, and Messages. This reduction is very noticeable and is not at all "normal."

To make sure I was not imagining this, I tried logging into my test dummy log in and sure enough, the sound there is loud and clear as normal. So the problem is only in this, my main Admin login.

I went into the ~/Library folder and deleted several sound pref files com.apple.soundpref.plist, com.apple.systemsound.plist and rebooted but it made no difference. I tried zapping PRAM. No effect. Something is corrupted somewhere but how to fix this??

I found one single Discussion topic on Apple's website about how the computer reduces sound by 50% if the machine is rebooted WHILE HEADPHONES are attached. This is described as a feature rather than as a bug... and the author of that post didn't explain how to reset the audio to "normal" conditions. This is, in effect, what happened last night while playing the Netflix film with that "external speaker" wire attached to the TV.

I am at my wit's end after spending 2 hours on this changing and altering everything I could think of. The only thing I can think of next is to do a clean reinstall of Mtn Lion. Any other ideas from you folks??

Re: Sound Problem!!

Posted: Sun Nov 04, 2012 10:27 pm
by Richard Serkes
As silly as this sounds, plug in some headphones and start any file that has audio. While the file is playing, unplug the headphones. I think the problem happened when the audio was going from the MacBook to the TV and the MacBook crashed. This experiment might "tell" you Macbook that you're through using the headphone jack.

Re: Sound Problem!!

Posted: Mon Nov 05, 2012 4:26 pm
by Bob Wiswell
I recently purchased a used MBP 15" running Snow Leopard. I have noticed that the sound is very low when using the internal speakers. I just assumed this was because this is an old notebook (mid 2007). The sound is fine when I use headphones. I compensated by using external speakers with it's own power supply and volume control and that works fine.

I did not realize this may be a glitch. I am really interested if anyone has an answer to this problem

PS: I have disconnected the headphones while something is playing and the sound is as it was originally, reduced/not very loud.

Re: Sound Problem!!

Posted: Mon Nov 05, 2012 5:00 pm
by Stephen Hart
Googling "MacBook Pro volume too low" yielded a number of possible solutions.

Did you check in System Preferences > Sound > Output and make sure you have Internal Speakers selected?

You might also look at Audio MIDI Setup.app and see if there's a setting there that's affecting your speakers.

Peek into the earphone jack and see if you see a light. That appears to indicate that the MacBook thinks it still has earphones in.

Check iTunes > Window > Equalizer to see where the preamp is set.

Re: Sound Problem!!

Posted: Mon Nov 05, 2012 7:58 pm
by JerryFreilich
I did all the things you mention Stephen. But most importantly.... look at my posting... this is NOT a hardware issue!!!! The sound is FINE in another log in. Utterly frustrating.

Re: Sound Problem!!

Posted: Mon Nov 05, 2012 8:18 pm
by Stephen Hart
JerryFreilich wrote:I did all the things you mention Stephen. But most importantly.... look at my posting... this is NOT a hardware issue!!!! The sound is FINE in another log in. Utterly frustrating.
Some of the things I found seem to be login-dependent, the settings in iTunes, System Prefs and Audio MIDI Setup.

The only other thought I have is to hunt for a likely-sounding prefs file and try temporarily replacing it.

Re: Sound Problem!!

Posted: Mon Nov 05, 2012 8:42 pm
by JerryFreilich
Eureka!

(Or something less satisfactory than that....)

The problem seems to have gone away. I am forced to remember the scene in the Terry Gilliam movie "Brazil" when the protagonist tells the Central Services guys that his ducts "fixed themselves" and they laugh hysterically at him. "Things don't fix themselves."

I don't know which of my various fiddlings caused this to happen. But most immediately, I was in iTunes moving the volume slider up and down. I had done this 1000 times trying to make some effect. I had plugged in headphones and unplugged them. Jiggled the slider up and down. Unplugged them again. Plugged them in again. Moved the slider, back and forth. Over and over.

Well, at one point I used the KEYBOARD command key and the up and down arrows to perform this same task and all of a sudden the sound returned to normal levels. Why in the world this could possibly matter, I have no earthly clue. It fixed itself. You may all now laugh hysterically.

Re: Sound Problem!!

Posted: Tue Nov 06, 2012 9:24 am
by Richard Serkes
And the universe presents us with another conundrum.

Re: Sound Problem!!

Posted: Tue Nov 06, 2012 7:57 pm
by Jay Cline
Were you using the volume slider in the Netflix window to control volume? Do you know why the computer shut down while it was playing?

Re: Sound Problem!!

Posted: Thu Nov 08, 2012 10:45 pm
by 8string
I'm sorry. Thiskind of problem is not supposed to happen with Macs. Does not compute..
-steve jobs ( communicating to you from my special place in hell. ). Just joking, Jerry. Never experienced this before.