Hello,

The factory configured the Shaker 500 system to decrease the bass output with volume to protect the subwoofers in the doors at high volumes. Does anybody know if this soundprocessing is done by the headunit or is it done by the amps that power the subwoofers?

Thanks,

Scott

 

It is done by the Head Unit. If you swap head units and move over to an aftermarket solution with 4 volts or higher of pre-amp output, you may want to opt for something with a separate subwoofer volume.

 

Thanks for the reply. I need to keep the headunit because I bought a lifetime subscription to Sirius. I'm thinking of using a MTX RE-Q5 sound processor to restore the bass that the factory head unit rolls off with volume. I'm hoping the RE-Q5 will send proper bass to the door woofers and 12" sub ni the trunk.

Scott

 

How did you confirm this behavior? Does the Shaker 1000 perform the same bass reduction?

 

It is either a compression circuit or a loudness circuit that disengages as the volume is increased. I forget because I haven't rocked the stock HU since 2007 and I haven't used the shaker amps in over a year.

I am leaning towards a loudness circuit because at lower volume levels, many head units increase the bass and treble as part of the Fletcher-Munson curve. As the volume is increased, the loudness circuit gradually (or not so gradually) decreases.

 

That I get. Just like aftermarket radios have the loudness button. What I was asking was if someone had analyzed some test tones and confirmed it. I have never heard of this with a Shaker system. My Dad had a radio in an Oldsmobile that did that long ago. I remember the speakers had an extra wire running to them, which I always assumed was some sense wire to monitor when the woofers began to distort. I think it would have been cheaper to just use a slightly better speaker and forget all the extra engineering. It sounded terrible anyway!

 

Thanks for the replies. I have not measured the bass roll-off but I can hear it in my system. I have also found reference to it when searching the internet.

I am thinking of using the MTX RE-Q5 between my factory head unit and the factory Shaker 500 amps. The output from the RE-Q5 will go to the stock Shaker 500 amps and to the amp driving my 12" sub in the trunk. Does anyone have any thoughts on this set up? Will it work? My hope in doing this is to eliminate the facotory bass roll-off.

Thanks,

Scott

 

No offense, but I wouldn't waste much time on extra processing for those micro amps or subwoofers.

This is what the amplifier guts look like:


And this is one of the subs that have dual voice coils at 1.2 ohms each:

 

I agree with the factory amps and door subs not being the greatest. I am building my system one piece at a time as I can. I first added a 12" sub in the trunk which works great except for the bass roll-off at higher volumes. I decided my next step would be to correct the bass roll-off by adding the MTX RE-Q5 as described above. Following that, I hope to replace the Shaker 500 amps followed by replacing the 8" subs in the doors. Hopefully in the end the system will sound pretty good.

Scott

 

where did u tap for the signal for your sub