Audio heads, please school me

Matt

Silver Supporter
#1
02 LTZ with Bose but upgraded Pioneer AVH-X2800S HU. I replaced my front passengers mid with a new OEM one the other day because it was fading in and out occasionally with bumps or turns. Not all the time but enough to be annoying. Turns out it doesn't look like it was the speaker but it could either be the harness (Metra) or the amp. I'm leaning toward the amp.

If I looked at replacing the whole system but keeping the tweeters in the dash, mids in the front doors and coaxials in the rear doors, what exactly would I need to do? Can a fit a new amp in the space of the old one? Do I need to run an amp to have front components and rear 2 ways? How many channels would I need if I have to have one? I found that I could use the existing factory wiring from this writeup: https://www.trailblazerssforum.com/forum/viewtopic.php?t=10 Or, would I be better served just replacing the fronts and rears with Polk 6.5" coaxials and running new speaker wires?

What say you pro's?
 
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Reprise

Lifetime VIP Supporter
#2
Well, I'm not a 'pro', but I may be able to contribute here...answers are pretty much in order of your ask...

If you want to replace the speakers like for like (dash = tweets, and so on)... then components are your best bet, and the way to go in that case. More on components when we get to your other questions...

New amp in same space... sure...depending on how big / powerful an amp you want. Since you're not talking subwoofers at the moment, a 4-channel would probably be fine (yes, I know you'll have 6 speakers, with components...no worries). Something in the 200w RMS range would be fine (sounds like you're just wanting more or less a 'like for like' swapout) If you go with a *really* powerful amp, then give some thought to either relocating the amp, or getting some sort of 'squirrel cage' blower / fan for it (which takes up addn'l room, of course)

Since you're suspecting the amp - I think the OEM Bose amps are really starting to show their age - I have one in both my Voy and Sierra, with a 3rd one I got from a forum member...and *all* 3 have an issue (not with the same channel). So I think if you want to stay amplified...get a new one. My .02 on that.

Running component speakers off the HU, instead of an amp... it can be done (just make sure the HU and speakers are the same (almost always 4ohm). BUT - components really 'deserve' an amp to make them sound their best. And (IMO) most people who run components do so because they *care* about the sound quality (you're splitting off the appropriate frequencies to be handled by the right speaker - which will be better than sending 20-20K to a full-range (yes, they have internal crossovers built-in, but it's not quite the same.)

So how do we hook up 4 (assuming 2 tweets, 2 mid-bass) speakers to 2 front channels? Via an external crossover network, usually (these days) on a PCB (one per LH/ RH channel). You run the outputs from the HU to those crossover boards, then to the speakers from the connections on the PCBs, and they split the frequencies to go where they should.

Downsides to components (I'm sure there are more, but I'll list two...)
- They generally require more power to sound their best (so you should budget for an amp)
- If not properly placed, the discerning ear can 'localize' the sound from each.

Re: the Polks, specifically...
This would be a cost-effective solution, if you decide to skip the amp, and go with a simpler solution. They can be run with an amp, too, if you like. You'd want to run new wiring from the HU to the doors. The Bose amp has the crossover built into it, so if you retain that amp, things get dicey with regard to frequencies sent per wire, ohm load, etc. Another reason to ditch it, IMO.

BTW, I didn't view the link from the TBSS forum that discusses this scenario (?), but will do so now.

(on edit - now that I've viewed it, it discusses retaining / using factory wiring left over from removing the amp. This *can* work, but if you're 'going component', remember that you'll have to plan for your crossover network (since none will be present after the Bose amp goes bye-bye)
Since you have the 'oddball' '02 (IIRC), just make sure the wire colors correspond - I'm pretty sure they were changed at least once during the model run.

Finally, I'll add...re: harness. I love using them, and if you want chimes, OnStar, etc. - these fill the bill. I like Metra, myself (no trouble in either the Voy or Sierra); others like the PAC harness, and I think Crutchfield even sells a 3rd vendor now (although I'd look someplace else for it, cheaper)
 
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OP
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Matt

Matt

Silver Supporter
#3
Thanks @Reprise I think the simplest solution for me at the moment is to run Polk components in the front (in the OEM positions) using the Polk crossovers and run new speaker wire for them and the rears. I already have the harness because of the HU upgrade that's about 2 years old.

I'll keep the OEM wiring and amp in place so that when (not if) I get rid of the truck I can connect it all back up to OEM and keep the good stuff. So, it looks as though the only PITA part now would be running new speaker wires through the door boots.
 
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littleblazer

Gold Supporter
#4
My amp is under my seat but the way I'd do it is the same. Run line level rcas from head unit to new amp. Now you're replacing the speakers or keeping the stockers?

If replacing the speakers run leads to the doors. For the component set up wire in your crossover under the dash and then throw your leads to the respective location. Basically what I did and was already said
 

Reprise

Lifetime VIP Supporter
#5
I'll keep the OEM wiring and amp in place so that when (not if) I get rid of the truck I can connect it all back up to OEM and keep the good stuff
Sounds good. I'd recommend pulling the power / output plugs from the Bose amp before snugging everything up - that way, you'll have no potential for (parasitical) electrical drain.
 
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Matt

Matt

Silver Supporter
#6
My amp is under my seat but the way I'd do it is the same. Run line level rcas from head unit to new amp. Now you're replacing the speakers or keeping the stockers?

If replacing the speakers run leads to the doors. For the component set up wire in your crossover under the dash and then throw your leads to the respective location. Basically what I did and was already said
I'm replacing the speakers but keeping the stockers for when I get rid of the truck.

Sounds good. I'd recommend pulling the power / output plugs from the Bose amp before snugging everything up - that way, you'll have no potential for (parasitical) electrical drain.
Absolutely I'll be pulling the leads from the Bose. If I get an amp I'll be putting it in the same spot so the amp may very well be pulled out completely and stored in the basement.

Would I be able to pull power for the amp from the post on the rear fuse box?
 

littleblazer

Gold Supporter
#7
I'm replacing the speakers but keeping the stockers for when I get rid of the truck.



Absolutely I'll be pulling the leads from the Bose. If I get an amp I'll be putting it in the same spot so the amp may very well be pulled out completely and stored in the basement.

Would I be able to pull power for the amp from the post on the rear fuse box?
You can do it that way. It isn't recommended but you can do it that way. The lead for he rear block isn't the largest...
 
#8
Would I be able to pull power for the amp from the post on the rear fuse box?
I remember there were differing opinions on whether or not to do this for subs, and someone finally did the math on how much wattage you can pull that won't overload the mega fuse in combination with everything else in the rear block. I don't remember what that was though... :dunce:

FWIW I ran my first amp (for my 12"s) from there, only maxed at 300W, and was fine for years. Once I upgraded to a 5 channel, I pulled straight off the battery. :twocents:
 
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Matt

Matt

Silver Supporter
#9
Thanks guys. Looks like, when I do put in a new amp, I'll pull it from the battery.
 

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