Although the Dynavin N7 is advertised as working and integrating with DSP, it’s not quite as straight forward as it first appears.
If you’ve got the DSP amp installed in the right cubby hole in your boot, check if you’ve got one sub-woofer or two. If you’ve got two you’ve got the premium sound system and once you’ve spent hours pulling your car apart and fitting it all you’ll discover you’ve got no sound.
On the Dynavin head unit go to the telephone screen as if you were about to make a call, enter *123456# and press the green telephone button as if you were going to ring someone, this takes you to the hidden menu.
Press the words “car type” and change it from E53 to E46, then click ok to restart the Dynavin, sound may or may not issue forth.
If you still have no sound, go to the “sound” option on the main screens and
the box that says “OE DSP amp”, you should then have sound.Then you just need to get the balance right between the DSP output and the Dynavin output to avoid distortion and give you gradual volume control.
Alternatively, if you’re close enough, pay them to fit it!