I want to deprogram my rear speakers' EQ

[HextallS550]

727-01-01 : 1850 F000 44CC

Correct? What will this do?

Should remove ESE. I'm going to do the opposite and add it to my GT just to see what I find.

What's your end game BTW? Aftermarket amplifier and speakers or you just want to be done with the digital signal processing BS?

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[cking]

Should remove ESE. I'm going to do the opposite and add it to my GT just to see what I find.

What's your end game BTW? Aftermarket amplifier and speakers or you just want to be done with the digital signal processing BS?

My goal is to first correct the as-is system. Which to me means the stereo is for music, so no fake noise. Then to restore some bass as I like loud music. My living room has 6 Klipsch folded speakers and 1500 watts. When I watch Jurassic park my drink ripples, when I watch HEAT my neighbors think I have machine guns, Stairway to heaven is only good when you can hear the cross channel echo. Super clean and loud.

So after the ESE and roll off is gone then I can evaluate the system mainly the performance of the speakers, which I'm thinking is a little amp and kicker, and probable tweeters as the system seems weak in top and bottom.

So which value at 727-01-02 do set for no roll off ?

 

[Spart]

Waiting on RCA's

I'll take one as soon as you can ship them. I don't have everything together yet, but that is definitely the starting point.

 

[West TX GT]

Waiting on RCA's

What exactly are these harnesses? If it is an easier way to add a DSP and aftermarket speakers with an amp, put me in line to lay my money down. The final pieces for my sub install are on their way but front sound stage has me stumped.

 

[Rick#7]

Was there ever an answer to the OP for eliminating the bass roll off to the rear speakers?

After reading through this thread twice, as well as other threads and following links to similar threads on other forums, I haven't seen a definitive answer that was confirmed to work. The reason I ask is I have a V6 car with the base 6 speaker system, and I was about to buy replacement speakers because of how crappy the rear speakers sound. Then I saw this thread and learned about them not getting a full range signal. The speakers themselves may still get upgraded later but I feel that's a waste of money at the moment if they aren't getting a clean full range signal to begin with.

So, from what I've read on the subject I think there's only 2 options that will actually work to get rid of any factory EQ programing or bass roll off, and if it does away with ANC and ESE at the same time then so much the better (does the V6 even have these? I've only seen it mentioned regarding the EB and V8).

Option 1; replace the ACM with an aftermarket head unit, the issue here is both cost and compatibility. I would want a head unit that retains the steering wheel controls and hopefully interfaces with the SYNC module (that's the APIM, is that correct?), and keeps the voice command feature functional. If there is a head unit that retains all of those features, it won't be cheap! The only reason I can think of this wouldn't eliminate any frequency roll off and be able to send a clean full range signal to all the speakers is if that programming is in the APIM, but based on what I've read here I don't think that's the case, can anyone confirm that?

Option 2; use FORScan to change the factory ACM speaker level output to line out, then make a wire harness to adapt the output wire to RCA, connect it to a 4 channel amp and run that back to the speaker wires in the original harness. According to info on another forum, when the ACM is reprogrammed to line level output it provides a very high quality, full range pre-amp signal. Does anyone know for certain if this is true or not?

 

[HextallS550]

Was there ever an answer to the OP for eliminating the bass roll off to the rear speakers?

I've said this before, NO. Besides, there is no reason to turn off the rear only. Just turn it off universally.

So, from what I've read on the subject I think there's only 2 options that will actually work to get rid of any factory EQ programing or bass roll off, and if it does away with ANC and ESE at the same time then so much the better (does the V6 even have these? I've only seen it mentioned regarding the EB and V8).

Your car doesn't have ANC or ESE

Option 2; use FORScan to change the factory ACM speaker level output to line out, then make a wire harness to adapt the output wire to RCA, connect it to a 4 channel amp and run that back to the speaker wires in the original harness. According to info on another forum, when the ACM is reprogrammed to line level output it provides a very high quality, full range pre-amp signal. Does anyone know for certain if this is true or not?

Yes it's true. It's also a higher voltage that is sent out and (compared to aftermarket) it doesn't clip even at max volume.

 

[HextallS550]

What exactly are these harnesses? If it is an easier way to add a DSP and aftermarket speakers with an amp, put me in line to lay my money down. The final pieces for my sub install are on their way but front sound stage has me stumped.

Here's one in progress:

 

[GTP]

OP here.

I think I will install a compact stereo amp with high-level inputs, near the main amp up front. Then run some short wires in parallel with the lower door speakers' amp outputs into the new amp. Then connect the rear shelf speaker wires to the new amp speaker outputs.

Make sense?

This assumes that the door speakers don't also have the bass rolled off. If so, then I am still screwed, and I return to the desire of deprogramming the EQ.

 

[Rick#7]

I've said this before, NO. Besides, there is no reason to turn off the rear only. Just turn it off universally.

Thanks for the info, it's good to know at least one of my listed options is a workable plan.

I realize I mentioned just the rear speakers when I was referring to the OP's question, that was only because his interest was specifically for the rear speakers. If there's a confirmed way to disable the bass roll off (other than replacing the ACM or going with a separate amp), I have no problem doing it for all the speakers, I just didn't see how to do it from what seemed like conflicting info. Did I miss something?

 

[HextallS550]

I think I will install a compact stereo amp with high-level inputs, near the main amp up front. Then run some short wires in parallel with the lower door speakers' amp outputs into the new amp. Then connect the rear shelf speaker wires to the new amp speaker outputs.

I have to ask why? What's the point of keeping the factory DSP/Amp Module when it obviously doesn't meet your needs or desires...

This assumes that the door speakers don't also have the bass rolled off. If so, then I am still screwed, and I return to the desire of deprogramming the EQ.

Why are you screwed? Use FORScan, change the digit, and continue with your build.

 

[HextallS550]

Thanks for the info, it's good to know at least one of my listed options is a workable plan.

I realize I mentioned just the rear speakers when I was referring to the OP's question, that was only because his interest was specifically for the rear speakers. If there's a confirmed way to disable the bass roll off (other than replacing the ACM or going with a separate amp), I have no problem doing it for all the speakers, I just didn't see how to do it from what seemed like conflicting info. Did I miss something?

FORScan. It's one digit in the hex code. This isn't the thread that discusses it.

 

[GTP]

FORScan. It's one digit in the hex code. This isn't the thread that discusses it.

I have read every post, and maybe I missed it. But I thought the "flat EQ" parameter was never identified? Of course this is the superior way.

And yes, I don't care if the door speakers receive full range after the change.

 

[GTP]

I have to ask why? What's the point of keeping the factory DSP/Amp Module when it obviously doesn't meet your needs or desires...

My idea works only if the bass rolloff does not occur in the factory amp, and equally on all channels.

Again, this is all made more difficult by the fact that I cannot inject my own analyzer signal to see what's what and where.

 

[HextallS550]

My idea works only if the bass rolloff does not occur in the factory amp, and equally on all channels.

Again, this is all made more difficult by the fact that I cannot inject my own analyzer signal to see what's what and where.

The roll off occurs in the ACM. My question is why keep the factory amp? If you want to test the amp itself it's pretty easy. You buy the parts and I'll make you a harness you can test with.

I have read every post, and maybe I missed it. But I thought the "flat EQ" parameter was never identified? Of course this is the superior way.

And yes, I don't care if the door speakers receive full range after the change.

It was solved awhile ago. 727-01-02: 00xx xxxx xx Confirmed with a lab grade scope.

 

[Quackfoo]

Guys if I figured it out, anyone can. Just listen to what Hextall is telling you and it'll all work out. He knows his stuff.

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