Sound issue with Mojave

Has any one experienced sound issues after upgrading to Mojave? I have a 2013 iMac (3.5 GHz Intel Core i7). After upgrading to 10.14, internal speaker sound output has been reduced by roughly 50%. Additionally, my BT paired Beats Pill+ sound output is bear audible. Oddly enough, the internal speaker output returns to normal levels a few minutes after pairing with the Beats Pill+, despite no output from the Pill. I also note that the volume control in the Menu Bar is no longer synchronized with the volume control in iTunes. Despite pushing both to the maximum level, sound output with the internal speakers is significantly reduced unless the Pill+ is paired.