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bypassing JBL amp without removing bluetooth functionality?

Discussion in 'Gen 2 Prius Audio and Electronics' started by krooster1234, Aug 3, 2005.

  1. krooster1234

    krooster1234 New Member

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    So I've been thinking about ways to bypass the JBL amp without removing the bluetooth handsfree functionality (with the "premium" JBL sound system). I must admit, I don't remember exactly how the amp is wired from when I installed my sub, but would the following be feasible:

    1. Replace the head unit with an aftermarket unit with a built in amp. Wire this head unit to the front and rear door speakers, so that the JBL amp is not handling any of the music.

    2. Wire whatever channel handles the bluetooth audio (I believe it's the front left speaker's channel) from the JBL amp to the CENTER speaker (it may be necessary to replace the center speaker, I wouldn't know).

    This way, when you get a phone call, you would hear the ringing from the center speaker. It wouldn't mute the music, and the music may drown out the bluetooth ringing, but your LCD screen would show that someone is calling and you could simply power off your head unit manually and take the call.

    Also, and I HIGHLY doubt there is a way to make this part work, I'm wondering if there is some sort of signal in the JBL amp that designates when to mute the audio signals coming from the head unit (like a simple logic high = music on, logic low = music off and bluetooth audio on). If there is such a signal, maybe it can be wired to the aftermarket head unit in such a way as to power off the head unit when a phone call is being received.

    So, can anyone with more knowledge about the JBL system comment on the feasibility of this?
     
  2. tmorrowus

    tmorrowus Member

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    I have done a detailed study of the JBL system that should answer most of your questions, at

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

    You will have to replace the front speakers because the crossover that sends highs to tweeter and lows to woofer is located in the JBL amp. You can wire it so that the new head unit left channel speaker signal feeds into the nav system, which feeds the left speaker. Just like before. That should at least mute the left speaker when you get a call (although not the other speakers). There are wires labelled MUTE and N-MU on the harness that feeds the JBL amp... it may be possible that these serve your purpose, although my very limited testing didn't find them useful.
     
  3. krooster1234

    krooster1234 New Member

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    Re: bypassing JBL amp without removing bluetooth functionali

    Wow. You are awesome. Thanks for putting that together... especially thanks for doing frequency response curves using the factory equalizer. Now I know why it sounds like crap when I move the bass or mids from 0, and why it sounds better when I increase the treble!
     
  4. NuShrike

    NuShrike Active Member

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    Five
    Re: bypassing JBL amp without removing bluetooth functionali

    So bluetooth is in the HU then, and not the amp? That would be another reason the HU can't be changed out.

    Also, there is a higher possibility of feedback by routing bluetooth to the center speaker due to the closer proximity to the mics near the sunglasses flip-storage area.
     
  5. tmorrowus

    tmorrowus Member

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    Bluetooth is in the Nav system, but it sends muting signals to the head unit that I think will pause the current CD if I remember right and mute the audio.

    Agreed on the feedback issue... I don't see any reason to move the bluetooth audio away from the left speaker. Keeping it in like that means that the nav system can mute the left speaker while giving audio directions. In fact if you had an aftermarket crossover in the left door fed off the woofer wire, I think the nav system would mute the whole left speaker rather than leaving the tweeter playing music as it does now.
     
  6. DanMan32

    DanMan32 Senior Member

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    You would want the new HU left front output fed to the NAV audio input, so it could control the left speaker sound source, switching between itself and audio. Mute is only done for BT or voice recognition.
     
  7. jfkaiser

    jfkaiser Junior Member

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    DANMAN32 could you please elaborate on this wiring possibility?

    Have a 2009 Pkg3 Prius with JBL stereo……..it SHOULD be similar to your 2008 Prius with JBL that you have on your website.

    1. Looking to replace the JBL stock head unit in my Prius with a Kenwood……BUT I really like the Bluetooth that is built into my Prius (not part of the factory JBL head unit although they DO route the Bluetooth audio thru the JBL amp), so I want to keep the Bluetooth that is in the car already and not try and enable my Kenwood to do that function.

    Question: I am NOT interested in going thru the JBL amp in the Prius (intend to use my own amp) so basically I just need a harness that lets me separate power/ground/acc type leads from the Toyota connector in the dash WITHOUT me having to go in and butcher a bunch of wires.

    Does the Metra 70-8117 fulfill this?



    2. I DO somehow want to keep the JBL amp alive since the Bluetooth caller’s voice gets routed thru the JBL amp…….so I do want it powered up and running……I just don’t intend on passing my Kenwood audio thru it. So my question regarding the JBL amp is that I am not sure how to give it any kind of “turn on signal†via special harness or whatever……so that I can have the Bluetooth caller’s audio pass thru there

    I understand that I am going to somehow need to switch my JBL Bluetooth callers audio into my speakers (via a relay?) and that I may have to design some sort of special circuit to mute my Kenwood while the Bluetooth caller’s audio is present

    Anyway regarding my need to “turn on†the JBL so it can amplify the Bluetooth callers audio……….any suggestions on how to send it a signal and from where that will power it on?

    Thx,
    Jon
     
  8. jfkaiser

    jfkaiser Junior Member

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    Hi Guys,

    Well being impatient, I decided to modify the Metra Prius kit that comes with the pocket and just basically used a clamp and combination square to cut the side Left and Right sections off of that Metra kit.

    I will probably install the Scosche double-din when that kit finally arrives, but for now this works and looks "ok".

    I started by simply using the TYTO-01 interface so that I wouldn't have to hack up my Factory radio harness for Power, etc.

    I was quickly disappointed to learn that although the Prius Bluetooth still functioned and dialed my cellphone........NO audio was heard thru the speakers even though the TYTO has an integrated digital amp turn on so I knew that the JBL amp was indeed turned on.

    I suspect that something in the switching of outputs OR the mute circuits does not function to allow switching of the Bluetooth signal to the JBL amp once you get rid of the JBL radio.

    So then I ended up going and buying the Kenwood Bt-200 Bluetooth adapter (had to flash it to newer firmware 1.60).
    I ended up only used the plastic dash harness connector from the TYTO-01 and NOT any other part of the TYTO-01 since I had already decided to put ina 5-channel Kenwood amp that I had sitting around from my old Ford Explorer.

    Be sure you look at Crutchfields wiring diagram as it talks about needing to have your aftermarket stereo's antenna wire go to a wire on the Prius harness that turns on the Prius antenna booster or something like that.

    I DID have to install the resistor as mentioned in the METRA kit instructions so that my climate control would work.

    I also hooked up the PAC SWI-Jack so I could use the steering wheel controls to control my Kenwood. Disappointed to learn that none of the telephone Bluetooth Kenwood stuff is controllable via the SWIJack/Kenwood combination.

    I had previously bought the Bazooka FAST harness which of course DOESN'T work at all with the JBL 3 connector harness in my 2009 Prius......BUT I just didn't want to cut any of the factory speaker wires......so I took a dremel tool to my FAST harness and basically left the middle section and cut off the two outside pieces.
    I DID end up using all three pieces but had to bend a couple of pins on one of them to allow me to grab the correct speaker wires........again the only benefit to this was that I didn't have to hack up the factory harness that plugs into the JBL amp under the passenger seat.

    I threw my 10" sub in the back. My Kenwood amp is under the back trunk storage area.

    It sounds GREAT and I am very happy with the changeout overall.

    Thx,
    Jon