Why does it shout at me? (Thoughts on the stereo system)

[LM7Tahoe01]

I’ve got an 01 Tahoe that doesn’t sound all that great.

Here’s the story: non-Bose system, previous owner installed a JVC R540 head unit. Sounded pretty rough, peak in the upper mids, no bass from door speakers, and they rattled. Factory sub worked fine. Yanked the door panels and found factory speakers with rotted surrounds. That explained the bass/rattle issues and I assumed it would also explain the nasty spike in the upper midrange (shouty vocals, overemphasized guitars, etc.).

I went to Walmart (yeah, I know) and bought some cheapo speakers for the doors, and that fixed the bass/rattle issues, but it still shouts at me.

I’m guessing the PO ran the head unit through the factory amp (still have warning chimes, factory sub still worked, etc.) and I’m wondering if that’s where the EQ issue might be? I’m thinking about bypassing the factory amp and just running the door speakers right off the head unit, old-school style. Anyone have any comments on that?

Just for information’s sake I’ve disconnected the factory sub and I’m running a Radio Shack Pro Series 12” sub driven by a Phoenix Gold R500.1 amp. Fun fact: I bought the RS sub brand new probably close to 25 years ago…

 

[iamdub]

Have you adjusted the JVC's EQ? It only has a 3-band, but you can exaggerate the lows at least just to test. It might have a bass boost setting that needs to be turned on. Also, if it's a non-Bose car, wouldn't it not have an amp?

Have a pic of your sub setup? I like old school audio like that.

 

[LM7Tahoe01]

I’ve played with the settings in the head unit, and it helped some, but it still doesn’t sound great. I was under the impression that there was still an amp in the non-Bose trucks, something has to be crossing over and driving the factory sub…

I’ll definitely grab some pictures for you… I know everyone loves pictures!

 

[LM7Tahoe01]

Too dark to get decent pics tonight…

Just in case it helps anyone my truck had the UP0 radio with UK6 rear controls and the UQ3 speaker system…

 

[LM7Tahoe01]

Here’s a quick shot of the sub! The amp is under the seat…

 

[iamdub]

View attachment 380397

Here’s a quick shot of the sub! The amp is under the seat…

Nice survivor! Brings back memories.

 

[LM7Tahoe01]

Just finished bypassing the factory amp, first impression: sounds much better!

 

[02LT]

Hey do you know where the non-bose amp would be installed by the factory in a non-console truck with the UQ3 enhanced audio system?
I'm installing a pioneer head unit in my kid's '02 tahoe and i can't find the oe harness for the amp. Now just 5 out of the 7 speakers are working. Rear door speakers aren't working.

 

[Doubeleive]

Hey do you know where the non-bose amp would be installed by the factory in a non-console truck with the UQ3 enhanced audio system?
I'm installing a pioneer head unit in my kid's '02 tahoe and i can't find the oe harness for the amp. Now just 5 out of the 7 speakers are working. Rear door speakers aren't working.

it's behind the glove box

 

[02LT]

So here is the amp, radio and the big hole i made in the dash. Still can't find the stinkin amp harness. Would it be coming from the right hand side from behind the glovebox door? both of those harnesses off the amp go into a much larger tape wrapped loom. the 20 amp fuse under the hood is good. i got the fuse diagram off this forum.

 

[Fless]

That underhood fuse diagram is for 2003-2006. Close but no cigar. Fuses are different for 2000-2002:

 

[Doubeleive]

So here is the amp, radio and the big hole i made in the dash. Still can't find the stinkin amp harness. Would it be coming from the right hand side from behind the glovebox door? both of those harnesses off the amp go into a much larger tape wrapped loom. the 20 amp fuse under the hood is good. i got the fuse diagram off this forum.

The radio and amp harness are integrated into the main harness, there is no separate harness
if you are simply trying to bypass the factory amp then you will need to connect your aftermarket output to the amp outputs and unplug the factory amp.

 

[02LT]

ok so the radio shows 2 plugs but I can't remember how many i disconnected when I took out the OE head unit. I DO NOT want to bypass anything, the rear door speakers aren't working. I initially bought a Metra 70-1858 and the rear door speakers aren't working. I called Metra and they said I need a 70-1859 cuz we have 7 speakers. I sent Metra a pic of the OE head unit and they said i have a second plug for the amp. The 70.1859 has two plugs (the main plug is the same as the 1858 but has a second plug) and one plug has a single red wire on it for the amp. I plugged the OE unit back in using the single OE harness and the rear door speakers don't work either. Thank you for the updated fuse diagram, just pulled that fuse (25 amp) and it looks good. I swapped it with the other 25 amp fuse for the wipers.)
Are we absolutely sure there is only a single harness for this OE head unit?
I called my local dealer and the parts guys confirmed it has the enhanced audio but i did not ask how many harnesses it used.
Could I have a bad amp? What else would cause the rear door speakers not to work. i thought I may have screwed up the Pioneer harness adapter but the OE radio has no rear door speakers as well......

 

[LM7Tahoe01]

Original Poster here coming back to the original topic… my truck definitely sounds better with the factory amp bypassed, but there’s still a definite peak in the upper midrange. It’s still a bit shouty. I’m thinking it’s got to be the cheapo speakers. I’ve played around with the eq settings a bunch but I just can’t tame it… Does anyone have any suggestions for some budget minded door speakers that actually sound decent?

 

[Doubeleive]

Original Poster here coming back to the original topic… my truck definitely sounds better with the factory amp bypassed, but there’s still a definite peak in the upper midrange. It’s still a bit shouty. I’m thinking it’s got to be the cheapo speakers. I’ve played around with the eq settings a bunch but I just can’t tame it… Does anyone have any suggestions for some budget minded door speakers that actually sound decent?

well not sure what your budget is but the infinity Kappa series are a pretty good choice, prices vary...... depending
I would shop ebay, amazon, sonic electronics.
beware of buying them with too good to be true prices on some websites, word to the wise, stick with a known dealer/retailer

 

[02LT]

What would you say is the easiest way to test the rear door speakers? Does anyone know what wires are the rear speakers coming out of the amp? What about the door harness? Is there a way of accessing the wires there? If the amp is bad how do you diagnose that?
THnx

 

[Doubeleive]

What would you say is the easiest way to test the rear door speakers? Does anyone know what wires are the rear speakers coming out of the amp? What about the door harness? Is there a way of accessing the wires there? If the amp is bad how do you diagnose that?
THnx
View attachment 395313View attachment 395315

you will have to find the wiring diagram for it, one of those harness plugs is the input and other is the output
should be here

https://www.scosche.com/media/guides/ct1031.pdf

 

[LM7Tahoe01]

I feel like this is going to get confusing. I am pretty sure my issue is poor quality speakers, I don’t think I need further assistance with that, I just have to find better speakers that fit my budget.

Let’s just focus on the new guy’s rear speaker issue now…


I would start at the rear speakers. Pull one and unplug it. Get any old speaker and see if you can jam its wires into the plug and see if it plays. If it does then the door speakers themselves are bad. If it doesn’t play further diagnosis is required…

 

[02LT]

Awesome! Thanks a lot, that pdf is great. I was told by Metra to use a 9v battery on the speaker wires (no polarity involved) to see if the speakers make a noise. Where can a replacement OE amp be sourced? Is there a cheap alternative that is plug and play or would i need more Metra harness adapters?

 

[LM7Tahoe01]

The 9v battery trick works too, but don’t hold the wires on, just tap them…