In-call volume too high after cm-12.1-20150806-NIGHTLY-d802

I did the upgrade to cm-12.1-20150806-NIGHTLY-d802 yesterday but now the in-call volume is too high, even when on the 'quietest' setting. It was OK before the upgrade.

I have looked through every setting on the phone all to no avail.

I read on another forum that someone managed to alter it with DSPManager, which I installed but can't seem to get it to make a difference.

Any help appreciated!