Sound muffled; hardware or software issue?

Question

Sound muffled; hardware or software issue?

When listening to the internal speakers on my MacBook Pro (15-inch, 2016), the sound occasionally becomes very muffled.

If I plug in external EarPods, the sound through them is perfect.

Here'e the odd part: unplugging the EarPods returns the sound to the internal speakers and it's no longer muffled.

So does this sound like a:

Hardware issue (as I physically have to plug and unplug EarPods to 'fix it' (temporarily) or a
Software issue (as the act of plugging and unplugging earphones is recognised by macOS as a command to transfer the sound).

I'll probably try reinstalling macOS soon to see if that helps but just wondered what you guys' views on this might be.

MacBook Pro 15″, macOS 10.15

Posted on Sep 11, 2020 7:57 AM

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Answer 1

Top-ranking reply

HWTech

Level 9

60,302 points

Sep 11, 2020 9:15 PM in response to The_Knowledge_Seeker

That is odd behavior. I'm not entirely sure. Before reinstalling:

Try a PRAM reset (hold the PRAM reset for a full minute to activate it several times -- sometimes it will just begin booting into macOS after 20-30 seconds).

Try booting into Safe Mode.

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Answer 2

Sep 17, 2020 10:30 AM in response to HWTech

HWTech wrote:

That is odd behavior.

I agree!

Before reinstalling:

Try a PRAM reset (hold the PRAM reset for a full minute to activate it several times -- sometimes it will just begin booting into macOS after 20-30 seconds).

Did that. I've got a MacBook Pro (15-inch, 2016) which doesn't play a startup sound so it was difficult to tell how many times it activated and, in fact, it only appears to take around ten seconds before moving on. But it DID do it at least once because it did its normal trick of showing the Guest account which it doesn't in normal mode.

Try booting into Safe Mode.

Tried that, too. Safe mode doesn't allow sound in or out so could only test it after rebooting into normal mode again.

Sadly, the problem remained. It took about 15 seconds of a youtube video before the sound went fuzzy again.

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Answer 3

HWTech

Level 9

60,302 points

Sep 17, 2020 7:11 PM in response to The_Knowledge_Seeker

The_Knowledge_Seeker wrote:

HWTech wrote:

Try a PRAM reset (hold the PRAM reset for a full minute to activate it several times -- sometimes it will just begin booting into macOS after 20-30 seconds).

Did that. I've got a MacBook Pro (15-inch, 2016) which doesn't play a startup sound so it was difficult to tell how many times it activated and, in fact, it only appears to take around ten seconds before moving on. But it DID do it at least once because it did its normal trick of showing the Guest account which it doesn't in normal mode.

FYI, if you look closely at the display you may notice the backlight flicker on very dimly about every 20 seconds or so (it is much easier to see in a dimly lit room). On some of the 2016/2017 USB-C MBPros and on all 2018+ laptops with the T2 chip Apple only allows one PRAM reset after which the Mac will automatically boot.

You can also clear the NVRAM by using the Terminal command line (I'm not certain if this is exactly equivalent to doing the PRAM reset):

sudo  nvram  -c

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