Volume triggered Muffled Speakers - 2016 MBP 15” Fault (w/ Video Demonstration)

Hello all,

I’m having an unusual problem with my Late 2016 Macbook Pro 15” with Touchbar (model shipping 17th December 2016).

Whenever playing audio that reaches a certain volume the internal speakers would become muffled. When lowering the volume the sound continues to be muffled. The only way to get clear sound is to either:

• Restart my Macbook
• Plug in headphones and pull them out again
• Type ‘midi’ into spotlight to enter ‘Audio MIDI Setup’ and change the audio frequency (Hz) of the Internal Speakers output.
• Killing the ‘coreaudiod’ process within terminal or activity monitor and restarting it.

Increasing the volume again will result in the audio becoming muffled again.

In this video I demonstrate the problem in detail.

I find this problem unusual as I’ve searched extensively for a resolution and cannot find anyone else with the same problem. I realise there was a problem around launch with bootcamp audio drivers breaking the speakers. However I had never used bootcamp and this problem started in the past week.

Here are the things I’ve tried

• I’ve reset the NVRAM/PRAM (on multiple occasions) [Via. boot keypresses & terminal]
• I’ve reset SMC (on multiple occasions, however as there is no confirmation I’m unsure if it really processed)
• I’ve formatted & reinstalled OSX Sierra (version 10.12.5)
• I’ve formatted & Internet Recovered OSX Sierra (version 10.12.5)
• I’ve downloaded an older version of OSX Sierra (version 10.12.2) and installed it.

Yet, the problem remains.

I decided to install Windows 10 via. Bootcamp and the problem no longer occurred. However after some use it started occurring. I believe it is harder to trigger the muffled sound as Windows 10’s maximum volume on the MBP 2016 is lower.

Apple Diagnostics report reference code ADP000 ‘No issues found’.

I’m tech savvy, however am stumped at what is causing this.

Hopefully some of you have some ideas?

At first I thought it was a software issue however after trying everything outlined above I no longer think this is the case. Do you think I should take my mac in for warranty? This is a last resort as I’d hate to be without my mac for a week.

See the full demonstration on YouTube here!

Keywords to help others search for this problem.

Poor Quality Sound, Low Quality Audio, Sounding Distant, Sounding Hollow, Sounding Underwater, Low Pitched, Distorted, Deep