when the engines cranks over before starting, there is a huge current drain resulting in teh lowering of the voltage. The empeg can handle this and puts up the battery icon as a warning. I get the same thing when I run the stereo with the car off for a few hours. The draw of the bass actually drops the voltage below the empeg's threshold. It sutteres the same symptoms. There is a circuit using capacitors which minimises this.
However...

when in tuner mode, the return of power alters the eq/sound settings.
This is abnormal.

Murray
Go-Wit-Da-Fro