[efunroom]

My car is 325 with HIFI option (OEM HU, OEM AMP, and analog signal between them)

OEM HU --> OEM AMP --> OEM Speakers


The dealer suggest the solution:

OEM HU --> OEM AMP --> AudioControl --> Aftermaket AMP --> Aftermaket Speaker


I suspect if the following solution can still work:

OEM HU --> Aftermaket AMP --> Aftermaket Speaker OR
OEM HU --> AudioControl --> Aftermaket AMP --> Aftermaket Speaker


Does audiocontrol is necessary when sound upgrade? which solution is the best one?

[fdiprete]

Been here, done that

The head unit has differential outputs rather than the more common line outs in most aftermarket head unit. The primary need for something in between the head unit and the aftermarket amp is driven by what the inputs of the aftermarket amp can accept. Some aftermarket amps can accept the differential signal from the bmw hifi head unit.

In addition to signal conversion from differential to line output, the Audiocontrol units - EQ or DSP - also gives you a way to shape the signal from the head unit, which in my opinion, is quite crappy.

On the output stage, bear in mind that the factory speakers are 2 ohms, not 4. Most aftermarket amps can drive 2 ohms at a higher power rating but check the spec.

So *if* the aftermarket amp you intend to use can accept differential line input then you could:

OEM_HU -> AMP -> SPEAKERS (oem or aftermarket depending on preference and amp capability)

if the aftermarket amp does not take differential inputs then you need something in between. Without an audiocontrol unit to shape the signal:

OEM_HU -> Line Converter -> AMP -> SPEAKERS

If you want to shape the signal: (this is what I ended up doing)

OEM_HU -> Audio Control -> AMP -> SPEAKERS

Technique may also offer some very good advice here, but first here is a link to my thread that goes into this ad nauseum.

http://www.e90post.com/forums/showthread.php?t=164359

[Technic]

Originally Posted by efunroom

My car is 325 with HIFI option (OEM HU, OEM AMP, and analog signal between them)

OEM HU --> OEM AMP --> OEM Speakers


The dealer suggest the solution:

OEM HU --> OEM AMP --> AudioControl --> Aftermaket AMP --> Aftermaket Speaker


I suspect if the following solution can still work:

OEM HU --> Aftermaket AMP --> Aftermaket Speaker OR
OEM HU --> AudioControl --> Aftermaket AMP --> Aftermaket Speaker


Does audiocontrol is necessary when sound upgrade? which solution is the best one?

What are you looking to accomplish? Which AudioControl product are we talking about?

The answers will determine if you can just follow the excellent upgrade of fdiprete or you need to do something else according to what you really want.