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Alpine Audio System improvements

Discussion in 'Roadster' started by mgemmell, Jan 29, 2012.

  1. mgemmell

    mgemmell Scottish chap

    Jan 11, 2012
    Madrid, Spain
    Hi all,

    While I am not considering changing the Alpine DDIN unit that came with my Roadster 2.5 I'd like to improve it.

    I just posted about how relocating the mic to the sun-visor area really has helped the handsfree phone performance, but I'd like to ask here about the speakers and in particular the subwoofer.

    We have noticed a problem: The subwoofer is not using the Alpine subwoofer output. It seems instead to be wired into the 4 speaker high-level outputs in such a way that it works regardless of the fader position. While this saves on having a separate subwoofer amp it means that the HPF (high pass filter) and subwoofer output level control are of no use. Ideally we should be able to control the subwoofer level independently and also be able to remove the low frequencies from the 4 smaller speakers (to reduce overload distortion at high volume levels).

    Ok, so here's the question... has anyone corrected this subwoofer issue? Have you added an extra subwoofer amplifier? Has anyone changed the stock speakers for better units?

    Many thanks

  2. NigelM

    NigelM Recovering Member

    Apr 3, 2011
    Northern Virginia
    *Warrenbonz* had his entire sound system customized...if he doesn't read this, try sending him a PM.
  3. S-2000 Roadster

    Apr 10, 2009
    I have not looked at the wiring in my Roadster for fear of voiding the warranty. However, I have examined the Alpine documentation quite a bit.

    My hunch is that the Tesla subwoofer has a separate amplifier with a built-in crossover. There's no way that the subwoofer is running off the 4 speaker powered outputs of the Alpine. Thus, when the line level outputs of the Alpine are lowered, the subwoofer lowers in volume, too. I do not know the brand of the subwoofer or its power amplifier (if there really is one, as I suspect, and/or if it isn't just part of the subwoofer product somehow).

    The full-range speakers are supposed to be Rockford Fosgate, and I believe that there is some sort of additional amplification besides the built-in power of the Alpine, but it's not the standard power boost accessory available from Alpine for similar head units.

    By the way, I believe that the rear outputs of the Alpine are unused, just like the subwoofer output.

    My hunch is that the audio wiring harness taps the Front Left and Front Right signals from the Alpine, then feeds them to both the Rockford full-range and the subwoofer amplifiers. I have no idea where in the harness the Y-split is made (if it's there). It's entirely possible that the subwoofer amplifier has full-range outputs as part of its crossover feature. The challenge, I believe, is to somehow connect the subwoofer outputs from the Alpine head unit to the subwoofer amplifier, perhaps defeating any built-in crossover. This should improve the ability to balance the volume levels between the full-range and sub, which is a feature sorely lacking from this $4,500 "option." The only question is whether the wiring harness has enough existing lines to allow the signals to be juggled this way.

    Has anyone torn into their Roadster who can describe what's in the subwoofer area, and/or how the full-range speakers are wired, and/or whether there is a separate amplifier for either?

    While we're on the topic of the subwoofer, the "enclosure" is very poorly designed for the power output levels, because I mostly hear plastic interior trim buzzing and vibrating with the bass. It's going to take a lot of professional work to make this sound good, which is a real insult considering a $1,500 stereo was billed at $4,500 on the invoice and was very poorly implemented. Even with the mediocre quality of the Alpine head unit, the Infotainment system could have simply been wired differently (at no extra cost besides the time to plan it right) and it would sound worlds better...
  4. W.Petefish

    W.Petefish Active Member

    Apr 29, 2011
    S-2000 has it pretty much on the money. EXCEPT the full range speakers are Alpine. (I looks at part number.) The amp is a non-standard item. (Tesla Specific, at least from the looks of what I think is the amp.)

    Goes a little bit like this:
    4 channel output > AMP > Crossover?? > Sub, Speakers, & Tweeters
    4 channel output > AMP & Crossover combo > Sub, Speakers, & Tweeters

    I have not torn into the SUB area, but that is just from what I've seen in the dash. If you have the cash check into some dynamat it helps the acoustics. If you go and get your sound system customized, use a reputable car audio place to do the install as the wires are not of standard colors. (nor is the color definition listed in the manual, any of them.)

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