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How do I get under the carpet?

Discussion in 'Gen 2 Prius Audio and Electronics' started by ScubaX, Nov 23, 2005.

  1. ScubaX

    ScubaX Member

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    2005 Prius
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    I completed my Kicker 4 channel AMP, Kenwood powered sub and Infinity speaker install. The AMP and Kenwood powered sub are in the rear hidden compartment. I ran the inputs to the AMP and the speaker outs down the right side under the kick panels. It runs along with the wire bundle for the rear electronics (Brake lights, tail lights, etc?). I am not sure what is in that bundle of wires, but I do know the slight buzz/hum I get increases and decreases with break usage.

    So first I tried changing over to a Novone LOC and using ground loop isolators. That did cut most of the sound but not all. Then I had new troubles with the speakers shutting off with bumps in the road. The LOC is the source (tapping it mimics the road bumps and speakers jump on and off). So its out and on it way back to Navone. I am not sure I want to put it back as it is of very poor quality workmanship. The first one arrived and the output RCA's were connected with bare broken wires showing and two wires were not even connected.

    Now I am using the Kicker's high level inputs and all is well again except the low noise that I can hear at low volumes. It is also there when the stereo is off and before the AMP's shut down via the Navone trigger. Pulling the inputs with the AMP on also ends the noise.

    Should I run the AMP inputs and speaker wires under the carpet and passenger seat? If so, how do I get it under there and without any bulges under the carpet?

    Thanks
     
    #1 ScubaX, Nov 23, 2005
  2. Lather

    Lather New Member

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    There’s plenty of room under the carpet. It’s loose with lots of space. I had enough room to add a layer of soundproofing material without anyone noticing. If you pull one of the seats and take the trim pieces off the sides (they snap off) you’re there.

    If I had to do it over again, I wouldn’t have unsnapped the wiring harness along the doors to unhook the carpet. It’s almost impossible to close them again. I’d just slit the carpet there and slide it out. It would have saved me a few hours.

    Another possibility is shielded speaker cable. Look up Belden 8718 or an equivalent. It might be easier.
     
    #2 Lather, Nov 23, 2005
  3. ScubaX

    ScubaX Member

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    Thanks for the help. I think I will try the under the carpet method. I believe the noise problem is incoming and not outgoing. The noise goes away if I disconnect inputs at amp. Also, I could barely reclose the trim with the current 14AWG Streetwires twisted pair I used for the speakers and Streetwires 18AWG 9 wire bundle I used for input. The Belden is 12AWG and thicker with the shielding. I don't think 8 cables of that will fit in the trim. If the noise continues with under the carpet install, then I can try that under the carpet.

    Also if I slit the carpet as suggested, how will the carpet be held in place at the trim?

    Thanks for the great help :D
     
    #3 ScubaX, Nov 23, 2005
  4. Lather

    Lather New Member

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    Sorry, I thought you might be using speaker wire for the speaker level inputs. Shielding it whould reduce noise. You should be able to find other manufactures and gauges. For example, Belden 8761 is 22 AWG. Shielded audio cable is fairly common.

    Regardless, there’s plenty of room along the hump. I don’t think 8 cables would be noticed. But...I thought the HV cables ran under there. There's a possibility that there would be more noise there than anywhere else. I don't know.

    The carpet is notched and held in place by the wiring harness clamp. If you push it back under the clamp, friction should hold it in place. The trim piece does more to hold it in place than the notches. If you pop open the harness clamp, try to close it again before deciding. I stripped the interior down to bare metal and those clamps were the only thing to stump me.
     
    #4 Lather, Nov 23, 2005
  5. ScubaX

    ScubaX Member

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    Do you know of an online supplier or brand name store for Belden cables? I seem to be able to only find bulk supplies at $400 and up.
     
    #5 ScubaX, Nov 23, 2005
  6. tmorrowus

    tmorrowus Member

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    I can't claim to be an expert on this matter, but my understanding is that shielding is not very effective on car audio noise. It's useful for high frequency stuff like radio and video, but the noises in car audio tend to be much lower in frequency and much less blocked by the shielding.

    I use Canare 4S8 twisted wire in my Prius install and don't have any noise. It's a twisted pair speaker wire and I use it for the signal from the JBL to aftermarket LOC, and for the speaker connections. I'm not necessarily recommending that particular wire since it probably is flammable due to cottonlike fibers inside, but perhaps the twisting of the wire inside is helpful to me in reducing noise. I have my wires running right down the right side next to the factory bundle of wires.

    Before doing any elaborate rerouting of the wires, I'd try temporarily running a wire outside of the car or supported on the seats etc as a quick test to see if your noise is caused by proximity to the factory bundle.

    And of course make sure you have good grounds for your amplifiers, sanding down to bare metal and using a star washer.
     
    #6 tmorrowus, Nov 23, 2005
  7. ScubaX

    ScubaX Member

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    Thanks Tmorrowus,

    I will look into the twisted pair for input. I already have 14AWG twisted pair for the speakers. What AWG did you use for the input? The Streetwires wire I chose for input is a 9 wire bundle. It includes the ACC 12 I use for the remote. That probably does not help either. Where did you run your remote? Since I do have a Navone Auto Trigger N-902 I could run the power from my fuse/dist block.


    Edit: P.S. What LOC are you using? I was using the Navone, but have had a lot of troubles with poor workmanship on the wires. It was also shutting off speakers with bumps in the road.
     
    #7 ScubaX, Nov 23, 2005
  8. tmorrowus

    tmorrowus Member

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    I used the 14 gauge twisted wire for both speakers and input, just b/c I had it around. You could probably get away with a smaller gauge for feeding the LOC and it would be better (smaller twist diameter meaning even less noise).

    I wouldn't worry about having the remote wire in proximity to the signal wires. The current running through it is very low and DC so it shouldn't cause any problems. I ran mine alongside the other wires.

    I have found the Navone LOC isn't as great as I had hoped... see my tests at:

    http://tom-morrow-land.com/tests/navoneloc/

    I'm about to experiment with some other options, like perhaps the AudioControl LC6, or more likely using the balanced signal from before the JBL amp alongside with my own volume control, either straight or through transformers.
     
    #8 tmorrowus, Nov 23, 2005
  9. ScubaX

    ScubaX Member

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    My Kicker 4 channel AMP and Kenwood powered sub have speaker level input. I think I will stay with that for now and look for the sound problems. I only went with an external LOC so I could use RCA's and add a ground loop isolator. The noise is still there with that setup though.

    I used the battery neg for my amp ground. I also added an 8AWG ground cable running along side the stock ground cable. I sanded the spot to bare metal.

    I will try and come up with some 18AWG twisted pair for the input to the AMP. I will run it over the seats first and see if that cuts the noise.
     
    #9 ScubaX, Nov 23, 2005
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