Iggy

It was a PIA to do for this novice, but I think it came out allright. I lost the pass through but kept the trunk space in tact. The pass through is there to facilitate handing beers to the ugly chick in the trunk, and seeings how there won't be any ugly chicks in my car it's not a problem.

Anyway, now I have to wire this sucker in which is gonna be a lot of work. I am starting to see the light at the end of the tunnel though.

Southbound

Iggy,
Again nice work! But are you sure you won't miss having a place to pass BECKS bottles back and forth? LMFAO!

You said that your new speakers sounded really nice with just the stock amp. Did you find they were too bright? With nice components mounted up high and good coaxials in the rear, I would expect them to sound really bright with the stock EQ. Where did you have to set the treble control to sound right? Once I replaced all four of my BOSE POS, I have found it to be a bit too bright. But cutting down the tweeter mod helped a lot. I guess your crossover probably has a similar adjustment for the tweeters... The two effects are different between just turning the treble down and cutting the tweeter level down. Turning the treble down will start to "ROLL OFF" high frequencies at some attack point. From that point upward the frequencies will be more and more attentuated. The rolloff may be 6db or 12db or even 18db per octave depending upon how many reactive poles are involved. With the treble control, if you turn it down to drop 6db at 5Khz, you will be down another two octaves, or another 12db or 24db or even 36db at 20Khz. However, when putting a series resistor into the tweeter circuit, you are dropping ALL of the frequencies equally. So if you put a resistor in series with the tweeter to drop it down by 6db at 5Khz, it will still only be down 6db at 20Khz. It's important to realize the difference between these two types of response control. A combination of both is great to achieve the optimum effect. But then a 1/3 octave graphic equalizer would provide that "selective" attentuation, but you're not going to find that in many car stereos... A single treble control just can't do that. It has to start somewhere and then just keep rolling off. I suppose it could have a shelving frequency where it quits attentuating further, but again which box is doing what in this stupid BOSE system?

In any case you shouldn't have to worry about that for much longer. This new amp ought to pump some real FLAT suds into those new speakers. BUT, I was wondering what other features the stock EQ amp might be performing? There's one nice feature about the stock system that I like. I like how it ramps the volume up everytime you turn the car on and off. It's a good way to keep from surprise sound blasts and helps prevent blowing up speakers. Once you have the new amp in place, I hope that feature still works with the EQ bypassed? Someone on the board reported that the basic bass and treble controls still work with the head unit after the EQ has been bypassed. That is a good thing... I just wonder if the "ramp up" circuit will still function? There's also a compression "soft clipping" circuit that is employed in the stock system. You will notice that you can never drive the amp into actual "clipping"... Rather, it utilizes a self gain reduction/compression stage somewhere before the final output stage. Hopefully with the new amp, you never have to push the old amp up into that range, but it's still a decent feature to have. Square waves and speakers don't usually mix... Again, I wonder where that protection circuit is located?

I will be most appreciative of any pics that you can post and/or detailed descriptions of the process involved to take the dash apart and get to the EQ for bypassing purposes. I will also be very interested to know how many of the stock features remain once it's bypassed. It seems pretty lame to design a box and install it only to put a high frequency boost into some cheap cardboard speakers Like I say, I have to wonder just what all the EQ box does do besides that?

Thanks for the great progress reports and posted pics. I'd love to hear the effects of bypassing the EQ with just the stock amp... But I don't want to wreck my dash trying to get to it. I also don't want to gut the stock harness just yet, because of warranty issues. If you find an aftermarket harness adapter that works with this TLS BOSE system, I'd REALLY appreciate knowing where to buy it. That way I could cut and double back the wires to bypass the EQ WITHOUT altering the factory harness. Then if the Headunit ever dies, I can put things back to stock before taking it in for repair. I'm sure the dealer will want to void things when they see the wiring harness all chopped up, etc...

KEEP UP THE GREAT WORK!!!
Southbound, but YOU can call me "Southy"

hemoglobin23

MAN!!!! That is one big amp...LOL...Looks cool though...What are the specs on that amp??? Looks good though...

Iggy

hemoglobin23 ,
Yeah it is very long, but it's only 2" thick. It's only a mediocre amp, but for $180 I could'nt argue.


Earthquake TNT900
Maximum output power: 900Watts
Output Power: 65Watts RMSx4 into 4 Ohms
200Watts RMSx1 into 4 Ohms
Bridged Output Power (5Ch): 200Watts RMSx2 into 4 Ohms
200Watts RMSx1 into 4 Ohms
Distortion: 0.015% THD
Frequency Response: 10Hz-35kHz +/- 1.5 dB
Signal To Noise: 104 dB
Low Level Input: 200mV-4V
Size(WxHxD): 8 1/2" x 2" x 16"

Iggy