HOW TO: Fix Bluetooth A2DP audio quality on Mac OS X

If you’ve paired a Bluetooth audio device with your Mac, even if it supports A2DP, you might have noticed how awful and rough the sound quality is. I’ve always put this down to Bluetooth being a rubbish standard when it comes to sound, but I noticed how good a set of Motorokr Bluetooth headphones sounded when I connected them to my Blackberry tonight, even though they sound awful on the Mac.

Turns out that OS X uses a horribly low bit rate for Bluetooth audio by default — who knows why. Perhaps it’s to allow for maximum compatibility with all devices.

The easy way to fix it is to copy and paste this line into your terminal:

defaults write com.apple.BluetoothAudioAgent "Apple Bitpool Min (editable)" 40

The “40” is the quality — depending on your Bluetooth headset, you can adjust it up for higher quality, or down if you have connection problems. 40 worked for me with a Motorokr S9 headset.

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19 Replies to “HOW TO: Fix Bluetooth A2DP audio quality on Mac OS X”

  1. Thank you very much for this useful tips! The issue with audio quality has been nagging me for almost two years, especially after noticing how much better the the A2DP quality is with a Bluetooth headset connected to basically any mobile phone (including iPhone 3GS) compared to the Mac. Your tip worked excellent with the SonyEricsson MW600 Bluetooth headset. I increased the parameter to 51 resulting in better quality than what 40 gave.

    Apparently the A2DP standard defines one mandatory codec, the low-complexity SubBand Codec (SBC). The SBC encoder use different parameter settings (sampling frequency, number of sub-bands, bitpool, channel mode, block length) to trade quality for bitrate. While the source is only required to support one such combination, the sink must support every possible combination that do not result in bit rates exceeding 320 kb/s for mono and 512 kb/s for stereo. However, the profile recommends encoders to support eight settings that results in bit rates ranging from 127 kb/s (mono) to 345 kb/s (stereo).

  2. Man, thank you very much for this great post. Saved my day! I coupled a Voiis Stereo Wireless Bluetooth Music Gateway with my MBP and the sound was horrible. With your help I could even use a quality of 60 which worked fine. Wonderful!!

  3. LEGEND!!! Took me a while to find the post but once I did sorted the problem out in 10 mins after trying a few values.

    Mate can not thank you enough… Let there be music!!!

  4. Thank you so much for this blog post. Audio Quality on my BOSE Soundlink Mobile was driving me nuts. I was already about to return them. I used „51“ and everything sounds fine. Haven’t played around with the values yet.

  5. : defaults read com.apple.BluetoothAudioAgent
    {
        “Apple Bitpool Max (editable)” = 64;
        “Apple Bitpool Min (editable)” = 2;
        “Apple Initial Bitpool (editable)” = 35;
        “Negotiated Bitpool” = 35;
        “Negotiated Bitpool Max” = 53;
        “Negotiated Bitpool Min” = 2;
        “Stream – Flush Ring on Packet Drop (editable)” = 0;
        “Stream – Max Outstanding Packets (editable)” = 15;
    }

  6. Thanks! Couldn’t figure out why my iphone 4 was putting out better quality than my MBP to my Bose SoundLink Wireless Speakers. Worked perfectly.

  7. Thanks so much for this. I was really annoyed the Jabra Wave+ with “crystal-clear sound” I bought for Skype use sounded worse than the built-in MBA microphone. I was able to turn the setting up to 53 at which point it still sounds noticably worse than cheap wired headsets but at least it’s usable.

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