Problem with ill audio sound, what could it be ?

[XPcentric]

Macbook Alu late 2008
OS X version 10.9.4
SSD Samsung (a couple of months old)

Incident: the audio output is suddenly 'corrupted'. Its like its ill, like it has a scratch in the throat and somewhat slower.

How it happened:
I listened to few music files when the sound was OK then I turned off Macbook.
I turned back on, I copied some music files from an external HDD and then the sound was no longer OK. It was not OK on either the new music files or the previous files I listened to before.
I tried to open the files with different software like VLC, Quicktime even with spacebar (preview) and still its not OK. I also tried restart.

Could it be the hardware ? I doubt it could be a virus. Or could I have pressed accidentally any shortcut to make any changes ?

 

[DeltaMac]

...
Incident: the audio output is suddenly 'corrupted'. Its like its ill, like it has a scratch in the throat and somewhat slower.
...
I tried to open the files with different software like VLC, Quicktime even with spacebar (preview) and still its not OK. I also tried restart.

Could it be the hardware ? ...

Is that distorted sound on the internal speakers only?
Did you check sound quality with headphones, too?

 

[XPcentric]

Thank you for advice DeltaMac.

Even on a cheap pair of headphones the sound is OK and so perfect in comparison. Now what do I do ? Do I prepare to spend some money or is there something I could try before ? Maybe some cleaning, could it be dust ? but can I be sure its of a hardware nature and not software ?

 

[DeltaMac]

I don't know for sure.
Maybe the speakers are blown (damaged) - or, a 6 or 7 year old laptop, so maybe the adhesive holding the speakers in place has dried out. Some double-sided sticky tape can be a good fix. The challenge will be getting to the speakers to clean them up and reinstall.

If you adjust balance all the way to the left (or right), is the sound less distorted? I'm just trying to pin this down to one speaker... And, it's also possible that the subwoofer is faulty. The subwoofer is attached to the right speaker.

You may be able to discover if one of the speakers is loose, by removing the bottom cover. The speakers are partly held in place with something like foam tape.

Do you get the same problem if you try something else that plays audio?
Go to youtube, and play a nice music video (your choice ), maybe with great bass. Listen to audio, moving balance control in your Sound Pref pane to get the effect. If you don't really hear anything (or you do hear distortion), be sure to try headphones, just to make sure of the difference - if that's necessary.

 

[XPcentric]

many thanks again DeltaMac, meanwhile I’ve done the following tests:

I booted from an external hdd and I confirm its nothing wrong with the software, its the hardware fault. I have almost always kept sound level to zero when booting up until now in order not to disturb anyone, but now I observed that even the startup sound of the system is distorded. Maybe the wearing off didnt happen suddenly - it rarely happened to me to have little noise when turning the volume to maximum, so maybe the wearing off was a little progressive ?!

After doing some research I’ve done already the test with Volume balance and Midi utilities checks, and it seems that both the right and left are faulty.
I’ve done also many other tests about sofware troubleshooting like reset PRAM, removing battery and holding down the power button for 5 seconds, etc

I’ve also dismantled already and brushed some dust, it was just one larger spot of dust, no parts seemed to be loose but I’ll check again and pay attention to that.

Hopefully the clues in this post will be helpful for future reference.

 

[XPcentric]

I opened again the bottom screws and what I discovered is amazing. Thank you for pointing out about the subwoofer, cause I would not even know it exists or could not recognise it by shape.

Hope this will be a lesson for people who will find problems with sound:
Although I'm an alien to audio hardware and software, Yes, I observed the subwoofer is the round box beneath my macbook and half of it's circumference is cut/cracked. Then, in VLC i tried alternatively Full Treble/Full bass and I confirm that is the issue, one could verify it easily if they ever play with audio software.

Now the problem remains:
1. I can play music again with software which offer effects such as Full Treble, but there are default sounds or software which might not have the option to disable the Bass hardware. - I want to find out how to do that.
2. I want to find out how much it costs to replace it, and if too expensive, to find out how to glue it myself, its a very thin piece which need handling with care.

Thank you DeltaMac, your the best!

 

[DeltaMac]

...
2. I want to find out how much it costs to replace it, and if too expensive, to find out how to glue it myself, its a very thin piece which need handling with care.

Not so expensive, you can likely get the speaker (right speaker plus the subwoofer) for less than $20.
Amazon offers them - and you can search for yourself with Apple's part number 922-8617.
http://www.amazon.com/Apple-Right-Speaker-Subwoofer-922-8617/dp/B003CO3GB6
Then, not so much more for the left speaker, too - so you can replace all at once.
http://www.amazon.com/922-8618-Left...=UTF8&qid=1422646239&sr=1-2&keywords=922-8618