Using rear channel wiring for front speakers

Yes I'm sure about the 2007. I respectfully submit the following diagrams for the 2004(5) and the 2007. You are right about the BT & nav audio being injected after the JBL amp in the 2004 diagram. This is not shown in the 2007 because it happens inside the JBL amp. The later model JBL has three signal connectors and is quite different from the 2004/5 model which has only two connectors. I hope this information is helpful to anyone concerned.

 

Here's a merge of the two relevant pages of the 2004/5 wiring diagram showing how the output of the JBL goes into the Nav. I've removed the wiring that is only present if you don't have Nav (stuff labeled "*4 w/o Navigation" in the digram).

 

How is the 2005's audio intelligibility from the BT & nav since it is confined to only the mid/low speaker that's aimed at your feet? In the 2007, the BT/nav is mixed to both tweeter & woofer--maybe sounds more natural.

 

Well Peakay, I see you subscribe to the adage "one good test is worth a thousand expert opinions." Good for you. I believe it too.

My test: Last year following some of the expert opinions on this board, I used just the rear outputs from my 2007 Prius to drive the front & rear audio. It sounded fine except there was no BT/nav audio. My cell phone went off and the system muted but I couldn't hear the caller. Had to pull over and disconnect from BT and call back using the handset.

The BT/nav audio and system volume control and tone control and fading and pretty much everything else, except the head-unit's analog "audio" content, are transmitted digitally from the head-unit/nav system via the "TX- & TX+" cables to the JBL amp where the commands are decoded and executed.

I've spent hours and hours working under the seat, behind the dash, inside the doors and center console experimenting, mapping, measuring voltages, levels and equalization to really know how it all comes together. I disassembled my JBL amp down to its circuit board to trace some of its logic to determine the best possible integration for my system upgrade. Much of this was documented in my early posts. Much was not.

For example, where does the center speaker get its audio signal? What's its level and bandwidth? Should you consider leaving it operational as part of your upgrade? Can you easily feed it just the BT & nav outputs or independently adjust its volume?

The answers to these and other searching questions can not be easily found in the available documentation. You have to figure them out yourself. And that's the real fun.

Hope you have much fun in your future. The adventure is just beginning.

Mr. Banjoman

 

The crossover frequency of my Diamond Audio speakers is around 3kHz, and female voices are centered around 200Hz. That means the vast majority of the sound for voice comes out of the mid-woofer.

 

Yes, you should be able to do that.

Interesting idea - never heard of anyone trying that.

If the sound hasn't already convinced you, once you pull the stock speakers you'll see how utterly worthless they are. Yeah, a lot of good speakers sound better with lots of clean power behind them, but the JBLs in the Prius aren't good speakers.

I've got a complete set of Infinity Reference component speakers including crossovers that you can have, for the cost of shipping. They were pulled out of my front doors when I upgraded to the Diamond Audio speakers. They've rolled around in my trunk and gotten banged up (one of the woofers has a big crease in it from something sitting on it), but I think they still work. I can't sell them like that, and I have no use for them, so PM me if you want them.

 

So, for my 2008 w/ premium sound system, I am still considering an aftermarket amp after the JBL to drive all 4 speakers. Would it be possible to splice a new amp's left front speaker output into the JBL's intact left front speaker wire in order to preserve Nav/BT sounds? As I am no electrician, I don't know if that introduces resistance, etc issues.

I guess I am still unclear, too, about what to do with the center dash speaker, which I believe adds something that's missing by having the mid-woofers so low in the doors.

 

Go back and reread this thread a little more carefully. If you're asking whether you can drive one speaker with two different amps at the same time, no that will not work, but there is no reason to do that either.

Preserving Nav and BT output on a 2004-2005 w/JBL depends on using the stock speaker wiring but does not depend on preserving the front left speaker output from the JBL amp. Preserving Nav and BT output on a 2007 (and presumably a 2008) does depend on preserving the front left speaker output from the JBL amp.

 

As you can see, I have an 08 model. Actually, rereading this thread was the source of my confusion initially. At first, many folks were not clear on the difference between 04-05 and 07 and later models. I'm trying to nail down the definitive answer that it is NOT possible to run another amp after the JBL AND preserve Nav/BT output to the speaker. This is certianly a disappointment to me, but at least replacing the speakers alone resulted in a significant improvement.

 

That is not correct, and I really don't understand how you came to that, or your previous conclusion.

You can recombine the front left woofer and tweeter signal and run that into amp, or you can bi-amp the front stage out of the JBL. Either one of those will preserve Nav and BT. It's only when you don't use the front left speaker signal out of the JBL amp at all on a 2007 that you lose Nav and BT.

 

OK, thanks much. I realize now that it's do-able, but will cost more by using a Cleansweep along with the amp, unless I use banjoman's homemade circuitry, which doesn't correct the JBL's internal equalization.

So, the remaining question to ask myself: Am I worth it?!?

 

I have a 2008 Prius w/ option #3. I just replaced the stock JBL front speakers with Focal VR165 speakers. Having used the existing wiring are they not being driven full range? If not, is using the rear channel output the only way to drive them full range? And if I understand this correctly from the previous posts ( I probably don't) if I disconnect the front channel outputs I won't be able to use (hear) my BT. Could the front output wires be connected to the center speaker for BT function? I disconnected the center speaker anyway to improve stereo imaging. The sound is much improved with the new speakers. I guess I want to know if the new speakers would sound better with the rear channels diving them. Sorry about the somewhat convoluted post. Thanks in advance.