Forgive me if I sound ignorant, or blessed considering I've only used Pioneer Premieres and Alpines... but why is the head unit so important if it's simply relaying signal to the external amp for real sound processing? Does the head unit modify the sound before pre-amp?
Other than the pre-amp voltages which may affect how clean the signal sends to the external amp, it seems that head units only differ between features, looks, and ergonomics. Or does it play a role before the signal gets sent to the ext amp? Thanks for clarifications.
the head unit plays a role before sending the signal out
you can have the best speakers and amplifier that money can buy but if the head unit is screwing up the signal then the speakers and amplifier will suffer
for example: head units can distort the pre amps that means the amplifier and speaker are going to distort also.. even if the amplifier gain is turned all the way down
just like any other component of the system, if the head unit allows interference from outside sources , that interference is a part of the signal sent out. also s/n ratios are different, build quality is different depending on the brand,
with all that said, the head unit is the source and if u have a bad source everything else will suffer