I tuned my 4 channel amp the other day with a dd1. I tuned for a cd and android auto. I got the same max undistorted volume for both which was 38. I have a pioneer nex 4500 and I use wireless android auto.. For android auto I downloaded the test tones and played it thru YouTube music. I played the exact same song thru a cd and apple music on Android auto. And android auto was alot louder. Did I use the dd1 correct for android auto? Are the recording levels different for the same songs on a cd versus like apple music, YouTube music, etc? And android auto volume cannot be controlled by my phone.