Acura RSX with Acura/Bose "Premium" Sound System

[kevinkr]

I have a 2002 RSX Type S with the Acura/Bose "Premium" Sound System. Last week the FM tuner in the head unit gave up the ghost and a certain amount of magic smoke (failed electrolytic) was released. This seems all to common with Matsushita oem head units as this happened on my previous two accords as well.. And I don't play music loud either - always just the tuner, cd changer and tape still worked.

Anyway on to some background and my question for the experts here.

I bought an Alpine cd receiver 9985 from Crutchfield, and last night wired up the pac oem2 adaptor that comes with the kit. Works great, and sounds considerably better than the oem piece of **** that came with it.

The installation was surprisingly easy despite some glaring omissions in the installation instructions and the head unit works great.

The head unit is currently driving the pac oem 2 which just basically converts the speaker level outputs to low level ground referenced outputs to drive the bose amplifier. The head unit also has line level outputs (4Vrms) and given the relatively high sensitivity of the Blose (oops) amplifier I was thinking even better results might be attained driving it with the pre-amp outs instead. The Alpine can turn off the internal power amplifiers in this scenario as well, functioning solely as a line level head amplifier.

Now I don't know what the input impedance of the Bose amp is, but I already know the sensitivity is high enough to drive the amplifier using the pre-outs on the head unit. Has anyone done this?

I used to work at that certain nameless entity, but rarely talk to anyone up there any longer, so I would feel uncomfortable contacting anyone there to ask this question, so I ask here.

I could of course modify the amplifier - that would actually be pretty simple to do. The changes to do this are pretty trivial actually, and the quality gain might be significant.. I worked on a lot of oem projects back in the day..

I am contemplating other possible changes down the road like new rear speakers which would require me to delete the EQ sections in the those amplifier channels. And maybe a real subwoofer with its own amplifier

[kevinkr]

Small typo the Alpine model I actually bought was the CDA-9885... Sorry..

[MadMutt]

Why not just run rca's to a replacement 'normal' amp.
Surely it would give much better sound quality.
Just watch the speaker impedance though.
bose like to run 2ohm rubbish...

[kevinkr]

Originally posted by MadMutt
Why not just run rca's to a replacement 'normal' amp.
Surely it would give much better sound quality.
Just watch the speaker impedance though.
bose like to run 2ohm rubbish...

I thought about that, but I think the weak point in the system is the speakers, and without the EQ in the amplifier I imagine they would sound frightful. I haven't actually opened up this amplifier yet, but my suspicion given the vintage is that it is probably six class D 50W amplifier channels based on a similar amp I did work on.

While I am tempted to replace the amplifier, I suspect that would have to go hand in hand with speaker replacement (except maybe those dash dome tweeters) and a massive amount of rewiring.

The acoustimass (tm) bass module is probably the single worst thing about this system. The mids and top end actually aren't bad at all now that I have disposed of the original head unit.

When I worked for Bose ages ago all oem amplifier and eq. automotive development was done without the oem head unit using AMS (a digital acoustical measurement system) to perform multiple position interior acoustical measurements.

Possibly the weakest point in the system was the head unit (made by Matsushita - probably for the lowest possible cost) followed by the "subwoofer" .. or the reverse? In either case... and then everything else.

[MadMutt]

Well, seeings how the h/u has a built in amp, run new wires to the doors and rear deck, then replace speakers.
Basically convert the car to a std 'deck and four'.

I don't think changing from a loc, to low level and modified bose amp input's, would be worth the effort.

It all really just depends on how much time and effort you want to spend on it.

[kevinkr]

Originally posted by MadMutt
Well, seeings how the h/u has a built in amp, run new wires to the doors and rear deck, then replace speakers.
Basically convert the car to a std 'deck and four'.

I don't think changing from a loc, to low level and modified bose amp input's, would be worth the effort.

It all really just depends on how much time and effort you want to spend on it.

I'll think about that, I figure modifying the amplifier to work with line level inputs is actually a lot easier than ripping this car apart to rewire everything - its got a 7 speaker system in it currently. The Alpine head unit is currently driving the Bose amplifier through an adaptor - was just hoping to eliminate that from the signal path.

[ppia600]

I would think the loc is using transformers on each channel to make the ground plane more flexible between the aftermarket head unit and factory amp. I wouldn't try to run directly from the head unit. It may actually sound better with the engine off, but with it running you may have severe noise issues. I too agree bose blose but if it sounds as good as you say, leave the converter until the speakers (or the amps) start having issues then swap it all out for aftermarket. Just my opinion

[MartyM]

Why did you use only the high-to-low level conversion?

If I remember correctly, the PAC-OEM2 will allow you to use the "line level" inputs for going out to your Bose factory amp.

Too much "hee-hawing" around in all these posts. Just try it. That's easy enough to do.

I've installed stereos in some of the most difficult "premium sound" systems in cars including Bose in Infinitis, GM, & more. with great success, bypassing factory amp or not.

What the other guys failed to mention is that if you remove the factory amp, there are no crossovers for the factory sub, tweeters, and so on. Hence there is more complication than meets the eye.

The crossovers are built into the amp on Bose & Infinity systems.

Just give it a shot. The results likely won't be significant, but it all depends on what makes you happy of course.

[ppia600]

"What the other guys failed to mention is that if you remove the factory amp, there are no crossovers for the factory sub, tweeters, and so on. Hence there is more complication than meets the eye."





/\ we didn't have to mention it.. he already stated he is aware of it.

[MartyM]

Well he said EQ, not crossover. But now I realize that's what he meant.

At any rate, the results can be really good removing the Bose amp. Did the same in a BMW Harmon-Kardon equipped vehicle.

Well must have been interesting working for Bose...!

Kind of dissapointed at the OEM "premium" speakers these days, including Bose, that are lightweight, ONE PIECE plastic-basket units!

Blah! Terrible!