MBP speakers sound bad; but is a software problem

[Namely]

My internal speakers sound broken, but according to Genius Bar it is apparently a software issue and they recommend an OS reinstall. I am hoping to hear some alternative suggestions.

A few days ago while playing iTunes, my MBP (unibody, late 2008 and in use since December 2008) began sounding bad. It sounded as if the internal speakers had blown. Not all songs produce ugly sounds, but within a certain sound range even classical piano music and relatively quiet songs with strong vocals now tend to become unclean-sounding/reverberate.

The Genius Bar employee rans some tests and concluded it probably is due to some kind of corruption of software, and he advised me to reinstall Mac OS.

He tested
1) if the mp3 file was damaged. Negative, a copy of it sounded fine on another MBP.
2) if the sound was bad when listening to my MBP with headphones. Negative, sounded fine on the headset.
3) if my MBP would sound bad when booted from another hard drive that played the same sound file. Negative, my MBP speakers now played that song just fine.

He also used disk utility and found no hard disk issues. He ran another test with disk utility, looking at a long list (that I don't know what is) but could not see any particular problem there, it seems.

I have subsequently tried to reinstall iTunes, but that has not helped, and am now hoping for a suggestion other than an OS install which I imagine can cause a lot of trouble (not so much the installation as such, but more the subsequent tweaking of various applications that I have had a great deal of trouble setting up).

Any second or third opinions on my problem?

Thank you for any thoughts.

 

[MacDawg]

If your MBP played the song just fine when booted from another HD, then I would have to agree it is not your speakers

You may not want do a clean install but, an Archive and Install should save all of your settings and still reinstall the System

If that doesn't work, you may need a clean install to ensure you have done everything you could.
I know it can be a pain, but if you want it fixed, you may have to take the time to work it out.


Woof, Woof - Dawg

 

[isaaclimdc]

Yup, sounds like at the end of the day, Erase and Install may be the only foolproof method of solving your problem.

 

[Banbeerd]

What you're talking about is an EQ issue. You have a range of frequencies boosted. Did you guys check for that yet? I've been into pro audio on the Mac for over six years and never came across this situation without the ability to easily fix it. (i.e. disable the EQ boost.)

 

[Namely]

Thanks MacDawg, isaaclimdc, and Banbeerd for your quick answers!
I will most likely go ahead with the reinstall, if no other effective suggestions comes along.
Banbeerd, regarding "EQ" -- which I guess mean equalizer; I'm no technician here -- the guy at the Genius Bar did suggest to set the iTunes Equalizer back to FLAT, but that did not change anything. In fact, I had turned on the iTunes equalizer for the first time about a week or two ago and was wondering if that might have been an influence.
I looked now at the Sound prefences but could not see anything I could fiddle with there... any specific suggestions to what I could try doing about "EQ" other than those two places (iTunes and pref)?
Thanks.

 

[Banbeerd]

Yes, EQ means "equalizer". (It also can mean "equalization curve".)

If your EQ is set to flat, then the EQ boost is coming from somewhere else. Have you tried playing the file in multiple apps? I've never heard of a software issue where a boost is always applied, but that's not saying it couldn't happen.

If you make a recording using SoundFlower and Garageband (or whatever recording software you prefer), I can analyze it and try to give you better advice. I wouldn't reinstall the OS yet. Most likely, that's just going to waste your time, considering there's no precedent for it to happen to begin with, so it will probably happen again unless you can find the source of the problem.

 

[chadamorrill]

Have you tried creating a new user and listening to iTunes logged in as that one?

 

[Namely]

[If your EQ is set to flat, then the EQ boost is coming from somewhere else. Have you tried playing the file in multiple apps?]
Ok, I'll try that and get back to you.

[If you make a recording using SoundFlower and Garageband]...
I am no sure what you mean. Using the internal MB mike recording something and sending that file? Or?

[There's no precedent for it to happen to begin with, so it will probably happen again unless you can find the source of the problem]

You have not hear about this problem before? I think its quite strange, so I really appreciate you point about reinstalling perhaps not solving the problem! Thanks. I'll report back later.

Thank you for your suggestion.
Sorry, I forgot to mention that bit. Yes, the Genius guy did set up a new user and the result was the same.

 

[Banbeerd]

[If your EQ is set to flat, then the EQ boost is coming from somewhere else. Have you tried playing the file in multiple apps?]
Ok, I'll try that and get back to you.

Let's just make sure we're clear on what I mean. Use something other than iTunes to play the file. Quicktime, VLC, Garageband, etc. We need to know if it's an iTunes-specific issue first.

[If you make a recording using SoundFlower and Garageband]...
I am no sure what you mean. Using the internal MB mike recording something and sending that file? Or?

No, SoundFlower allows you to route the audio data, that would be fed to the digital->analog converter in your Mac, somewhere else. You could record that in Garageband, possibly QuickTime (which might be easier), etc. I know you said that it sounded better through headphones, so this might be inconclusive, but it couldn't hurt to try.

 

[Namely]

Apologies for not investigating what you wrote before sending you more q's!
Ok, now I downloaded Sunflowerbed (great name:)... I can with this program record an example of my problem and send it for you to hear and analyze? I seem to have to identify an input program... Please advise how to proceed.

Ok, quicktime and VLC both sound bad with the sample file. will now attempt you next suggested step. A bit unsure what it exactly is I am supposed to be (previous post posted before reading your last post.)

 

[Banbeerd]

If all of your apps are giving the same results, I highly doubt I have a solution for you. But you should make sure to document this and get it to Apple if you have any means to do so, because this sounds like a very terrible thing to me. I certainly never want to have to deal with this.

I'll still check out an audio sample if you want to take the time to make one. Unfortunately, I don't have a Mac in front of me right now, so I can't give you fantastic instructions at the moment. However, let's see what we can do for the time being.

In System Preferences -> Sound, or the Audio MIDI Setup (I forget which...I typically use a third-party utility to switch things faster), you can select the system audio output device. Set that to be "Soundflower channels 1-2"(named something like that). Then, if you have Quicktime Pro, see if Quicktime allows for setting its input source to the same thing. If you don't have Quicktime Pro, you can do this in Garageband...it's just more clutter to go through, and again, I can't guide you through that right now. You can then hit record and make a few seconds worth of a sample. About five seconds is probably about as much as you can upload before you hit the 1.14 MB .zip limit for these forums, but that should be enough.

Let me know if you even want to bother. I might have better luck addressing the problem if I get this sample, but I'm not even confident I would have a solution for you then.

 

[Namely]

sample

I don't have Quicktime Pro, but Garageband is here. I think I figured out doing the input/output settings, but I am not sure what I am supposed to record and how. Audio software is totally new to me...
Thanks.

 

[Banbeerd]

Just set the input of the Garageband track to be the output of your system. (This should be called something like "Soundflower 1-2", meaning left and right channels.) Then hit record, and play a part of the track in any other application, like iTunes. Then we can find out if the audio is distorted before or after it goes to the digital->analog converter that comes right before the amplifier for your speakers.

One thing to note is that you don't have to set volume levels. Soundflower doesn't have volume control like you're used to using with the F keys in the upper right of your keyboard. You should set the output of Garageband to be your speakers, instead of Soundflower, though, so you can monitor what you record. This probably requires creating an "aggregate device" (which there are lots of internet tutorials on), but you could just record first, then edit the clip down afterwards, if you don't want to bother with that.

 

[Namely]

Sample

Hi Banbeerd,
Sorry for the wait. I have now made a sample using garageband...Is this usable for you? I appreciate your help very much and look forward to hearing what you can glean from it.
Thank you.

 

[Banbeerd]

Garageband doesn't seem to be able to tell me what format the original audio file was in, but here's an AAC (.m4a) file that represents exactly what I heard. I don't know this music, so I don't know what it was supposed to sound like. The only thing I experienced that could possible be considered "bad" is that there is a delay effect, but I assume that's just a creative decision that the producer made. I just mention it because you mentioned a problem with reverberation.

So, let me know if that echo is supposed to be in the mix, and if this file sounds any different to you than the version you had before.

 

[Namely]

Thank you for your response!
I am sorry for probably have wasted your time with the sample I sent you. The file was mpeg 1 layer 3 (and has echo-effect to begin with.). I chose it because it showed distortion when played in itunes, and because it was short enough for me to just dump it into garageband from the right sidewindow in garageband. I now realize that that method probably will not reveal how it actually sounds when I play it. I just dragged and dropped it because I cannot figure out how to record a file playing in itunes into garageband. I searched garageband and it says that audiofiles are added simply by dragging them in.
Maybe it is better til speak on the phone or chat if you have interest in doing that? (I am in Japan, so there could be a significant a time difference.)
Or are there any other software I can use other than quicktime and garageband? I'd prefer freeware/shareware.

 

[Banbeerd]

Well, it wasn't completely pointless, because now we know the original file sounds fine through my MBP. However, it doesn't sound like you made an attempt to use SoundFlower with Garageband. I think I already told you everything you need to do above, so why don't you try getting started on the process, and tell me where you get stuck?

Could you please tell me how the file I sent sounds on your machine, also?

 

[Namely]

new sample

Here you are, I finally figured it out, I think. This is another song. The file you sent back to me also sounded problematic. Look forward to hearing what you have to say.
Thank you.

 

[Banbeerd]

Fantastic. That recording sounds fine through my MBP speakers. Now, what I want you to do, is the same thing you did before, in terms of recording in Garageband. Except this time, make sure the system output is set to be the built in speakers, and the input of the track is the built-in microphone (unless you have a better microphone laying around). Just make sure that in Garageband, you have "Monitor" set to Off, on the right, under the "Real Instrument" tab. You can upload another .band file afterwards, and then I should be able to assess what I think is happening. Again, I may not be able to fix the problem, but this should be a fast process for you now that you know what you're doing, and I can at least tell Apple what the problem is, from an audio engineer's perspective, so that they can hopefully do something to prevent this from happening to you again.

(You will of course have to actually play the file. I'm going to recommend that you just do it from within Garageband. Just make one more "Real Instrument" track and use that. Then, you will have one track that represents the original recording, and another that displays how it is destroyed by OS X before it gets to the speakers.)

 

[Namely]

Here is a recording using an external mike. This recording sounds bad when I hear it in the headphones, too, so I think I did it right. (I played it via iTunes, not from within Garageband when I recorded it)

 

[Banbeerd]

I don't have my Mac with me today, so I can either listen later, or you could export the audio file (using the "Share" menu).

 

[Namely]

Here you go, an MP3 version.
Cheers

 

[Banbeerd]

Looks like the upload didn't happen, but in the future, please do not use .mp3s. MP3 is antiquated. AAC/M4A sounds better. (There are other formats that sound better still, but they won't play on Apple devices.)

 

[Namely]

Here is an AAC version. It is tiny for some reason. I hope it is usable.

 

[Banbeerd]

Well, it's been a day since I asked on a pro gear forum I frequent, and nobody has come up with anything to help you. I personally don't even recognize the type of distortion that you're experiencing. The best I can offer to you is to report the bug to Apple...

http://www.apple.com/feedback/macosx.html

...and if they get back to you, send them the original clip, along with the sample you just sent me. Or, more examples, if they're open to it.

I'm personally reporting this to Apple via their Developer Connection, so feel free to post any more clips you want to make, here, as I'm forwarding the address of this thread to Apple Developer Support.

Sorry I couldn't be of more assistance. I'm pretty positive it has something to do with Core Audio screwing things up on the way to the D/A converter, but I have no idea how to fix that, other than, as you have been told, possibly reinstalling the OS.