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Car audio hack. Bose system in Silverado. More power! Sub wires directly to amp?

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  • Car audio hack. Bose system in Silverado. More power! Sub wires directly to amp?

    So.... A chain of events has happened. The truck needs cleaned very bad. I removed all the seats and now removing the carpet. This sad sounding factory Bose sub is just staring at me. First I was going to just find another driver to install in the factory box and go. Then I thought adding a better amp on the sub should reduce the load on the main Bose amp and maybe sound a little better. Then I got to wondering if I can shoe horn a REAL 8" driver and a REAL amp in there. Happen to have an old PPI PCX1250 doing nothing.

    Assuming I can make this all fit in the center console, I have a few questions.

    1. My options might be rear firing or down firing on the sub. Thoughts?

    2. I will need to stay with a sealed enclosure. Both due to the need of a small enclosure, and I like more accurate bass.

    3. I will need to get signal to the bigger amp and was considering just feeding the speaker outputs from the little Bose amp right to the input of the PPI? I see that the PPI can handle up to 12V RMS on the input. Will I most certainly need a line level adapter? Is that just a series resistor?

  • #2
    It is not just a series resistor but rather a resistor divider network.

    As you know, your amp has the ability to handle speaker level inputs. But that capability is typically targeted at head unit's with output voltages normally limited by the car's nominal 12 V system. So the first issue is whether the Bose sub amp has an internal step-up voltage converter to supply more power to the original sub. If so, that may exceed the 1250's speaker level input limit. A power rating on the Bose sub amp may provide a clue.


    • #3
      Another thing to investigate is whether the Bose system is EQed for the factory sub. I'll bet money they have some subtle (or not so subtle) contouring going on in those systems. You could measure it, but you'll need a jig so you won't fry your audio interface with the output from the Bose amp. A cheap speaker level to line level adapter might work.
      Co-conspirator in the development of the "CR Gnarly Fidelity Reduction Unit" - Registered Trademark, Patent Pending.


      • #4
        Good point, it might be just as good to tap into the line level inputs from the head unit to the Bose amp since that amp is sitting only inches away from the sub. Entirely possible that they roll off some gain at max throttle to keep from blowing the little guy.

        I have studied the available area for a sub, as well as listed to the stock system without the sub to determine which direction to go. In short, what I REALLY want to do is throw it ALL in the garbage and start over. However, this is my work truck so I have to stay sane here. I think a high power 8" would both be an overkill for this system, but also may be impossible to fit without a big fight.

        So here are some revised ideas and looking for others.

        1. Go back to my original plan of replacing the stock sub in the Bose vented box. Run the OEM Bose amp
        2. Replace the stock sub in the OE box, and run a little Clarion 60W amp I have on the sub. The Clarion is tiny but pushes out very clean power.
        3. Rebuild a sealed enclosure for a good 6.5" sub, and run the Clarion amp.

        I was wanting to install my PPI 500W amp, but I just cannot fit that in the console area. This is a work truck so space is at a premium, as is time. I would not be above buying a better suited amp either.

        I think if I ran the OE vented box, I could get away with less power, but in a sealed box, sound quality should certainly get a nice boost, but I will need more power. I have a history of over powering as opposed to under powering speakers. They just sound better and as long as they are not pushed to extremes, things sound so much better. So it might be hard for me to use a 300W RMS rated 6.5" sub, and power it with 60W. I would hammer it with the 500W amp but again, I can't fit that guy.


        • #5
          If you can disconnect the amp without setting off the check engine light, you can replace it.
          if this looks like your model, here's the wiring color code:
          1. solid orange wire = 12v accessory
          2. solid white wire = extra its for the bose amp function
          Front RCA
          1. Left Front (+) = Tan
          2. Left Front (-) = dark green
          3. Right Front (+) = light green/white
          4. Right Front (-) = Orange/black
          Rear RCA
          1. Left Rear (+) = Brown/white
          2. Left Rear (-) = Brown
          3. Right Rear (+) = Dark Blue
          4. Right Rear (-) = Tan


          • #6
            Yep, though that one looks to differ slightly, I am willing to bet the amp and driver are the same. I took pics of the sub part numbers but it might not matter too much.
            So it looks like the amp brings in 4 channels and kicks out 5? an LFE channel? Any chance I can find a decent replacement amp similar enough?

            Really looking for thoughts on the sub. I am really torn. It appears obvious that I can install a 6.5" sealed sub without issue. However, we all know that bigger drivers don't have to work as hard to hit the same marks so an 8" "decent" sub may be able to perform on par with a really high end 6.5". Or? Anyone feel a sealed enclosure is less than ideal? Seems amps eat less space than an enclosure and space is tight here. Bummer that I turned loose of a really goo PPI 4ch amp a while back. Would have worked great here and had low level outs for another amp too.

            Dropcarve, it looks like the pic you have is also what I dug up. Someone made (you?) an adapter off the RCA outs from the head unit. Can I buy that somewhere? Not opposed to soldering one up, but thought they might be a buy item? I have to stick this truck together this week so I need to decide, and move. As many people here, I have "tweak-itis". Very hard to leave this thing stock. The sound is very puny.