Aftermarket HU Install with stock HK Amp and Speakers

[vanishm3]

OEM head unit bit the dust recently going to replace it with an aftermarket deck.

Wanted to double check I have this correct, taken from:
https://www.bimmerforums.com/forum/s...1#post26812971

My favorite trick to interfacing an aftermarket deck to a stock BMW amp is simple: use chassis ground on the speaker level negative inputs.

Basically, I do not connect the aftermarket decks speaker negatives to anything, simply insulate them. Once the positives are connected, grounding the amp input negatives drops the aftermarket decks voltage to a far more acceptable level. The deck then runs cooler and overall SQ is improved by not overloading the input stage of the amp.

If you meter the output of your stock deck, you will see all 4 speaker negatives are chassis ground anyway, so all it does is replicate the factory systems output.

So I am going to not wire and insulate the negative wires leaving the aftermarket head unit and then the negative wires coming to the head unit I need to ground them to chassis aka something metal, so bunch together those negative wires and ground them to a spot on the metal chassis in the dash

yes? no? thanks.

[82bmw633]

I just installed an Alpine unit in my 98 with the 10-speaker HK system. I just spliced in the existing wiring to the adapter and did not isolate the speaker grounds.

It sounds much better than stock and I have a lot more input options. If I wanted a truly stellar system I would replace all the speakers, the amp, all the wiring, and use a much higher quality head unit.