Replace DSP with active XO , in OEM Bose amp .

[CanisLupus]

I'm determined to complete this project though I know it will take some work . I have a car with a Bose amp that drives the following ; 3 tweets in the dash , a 6.5" in each of 4 doors , 2 subs in the rear deck .

The amp receives 4 balanced signals from the head-unit . They go into a A/D converter . I'm sure alot goes on in the DSP world but I'm not interested in that . At the other end there's a DAC . The DAC feeds a number of Drivers(chips).
My project is to put an active crossover between the inputs and the drivers . What I'm asking for is advice on the design of the XO (balanced) including which hardware would be suitable . I still need to find out which voltages +- are available from the on board power supply . Any help , ideas or advice would be greatly appreciated . Thanks everyone .

[richie00boy]

You need to put the crossover between the DAC and driver chips, which is complicated as it means you need to do the crossover in digital. If you try to put it where you say you may as well just dump the entire DSP.

[CanisLupus]

Yes , I'm wanting to dump the DSP . I don't want it . I could power-down the entire DSP area of the board but it also manages the driver chips on powering up (ramp-up?) . If I completely get rid of the DSP area , I will have to hardwire the driver chips , possibly with a delay for turn-on . The one XO design that I've found through websearch is from a site in the UK . (soton.ac.uk) Towards a differential crossover .

[richie00boy]

How much board area do you have to work with? I can't help think that the best option would be to ditch the whole thing and make a new amp and crossover unit, maybe in the same form factor.

[CanisLupus]

The board area available looks to be about 4" X 5" . A new amp and XO is another option and could very well be my choice , ultimately . The reasoning that I have for my idea is that the hardware is well matched , utilizes the balanced signal (noise cancellation) and would be less cost . I do love tinkering around in electronics and in the end I appreciate a good sounding system . rb , thanks for your comments thus far .

[Perry Babin]

Bose is known for using speakers that 'require' a lot of processing/equalization to produce an acceptable frequency response. Eliminating the DSP may leave you with a system that's virtually impossible to use unless you add additional equalization. Before you invest too much time in this, you should drive the speakers or the amplifiers with a normal/flat signal to see if the output is acceptable/usable without the DSP.

[CanisLupus]

That's good advice . I'll try to bench test to the best of my capabilities as part of the feasibility plan .