A little under a month ago, a Sound Booster user named Abby contacted me and reported sound distortions when using the app. She mentioned that she was using bluetooth speakers, and that the sound anomalies only occurred when she was using those speakers. I have a bluetooth headset, and it's used as a part of the routine tests performed with each version of Sound Booster before they are released. However, I have never noticed this happening and could not reproduce it on my end.
As luck would have it, several days ago I purchased a new pair of bluetooth headset. I was using it with Sound Booster casually when I noticed Abby's issue. Now able to reproduce the problem, I went to work to try to fix it. It turns out the problem only occurs if you are using bluetooth headsets and speakers, and only if the app that is playing audio (eg. iTunes) has its volume turned up to the max. My theory is that newer bluetooth headsets and speakers do their own audio boosting and calibration and therefore it would “double boosting” the audio that Sound Booster provides.
The fix is an added option in Preferences named “Bluetooth Volume Over-boost Protection”. It’s a mouthful but does describe what it’s supposed to do fairly clearly. It is on by default for all bluetooth headsets and speakers, and will protect you from over-boosting by encouraging you to use the volume up/down buttons on the bluetooth device and not from the app. Note that you will still be able to use system-wide equalizer, individual app volume adjustment, and other Sound Booster features with this new option turned on. Version 0.31 has been submitted to the Mac App Store and should be live any minute now. Thanks Abby!