Right. I should probably use the search for this, but anyways...

I just got myself a complete factory subwoofer set (subwoofer housing, overhead control and amp). My headunit (Pioneer DEH-P77DH) has a subwoofer output.

I really don't have any specific questions because I haven't started building it in yet. But anyone want to share some tips and tricks before I start? Things to look out for? Anyone have the same headunit with this factory subwoofer?

Did you get the wiring also?

The factory amp is wired into all 4 speaker outputs, you don't need your separate sub output. It's actually a Y type harness that goes between the radio and the existing speaker wiring with another set of wires running to the amp.

The only real trick to it is powering the amp. The GM radio powers the amp when it's turned on. The power is supplied thru 2 pink wires, both going to the same terminal at the radio end. Most aftermarket units don't have a power output that will supply enough current. The only thing they have is the power ant. lead which will drive a relay, but not an amp. I rigged up a relay on mine. I've heard of others just wiring the amp power to an Acc wire. I've also seen where someone separated the 2 pink wires and hooked one to Acc power and the other to the Power Ant. Inside the amp one is supplying power and the other is just switching it on with an internal relay. The only trick is figuring out which is which.

I had a link to an article on it which I can't seem to find right now. If I do I'll post it here.

quote Originally posted by DRH: Did you get the wiring also?

Nope...

quote The factory amp is wired into all 4 speaker outputs, you don't need your separate sub output.

Hmmmm. I would like to use the headunit's subwoofer output, so I can control the crossover.

quote I had a link to an article on it which I can't seem to find right now. If I do I'll post it here.

Yes, please.

Maybe I'll just bypass the the subwoofer's amp alltogether, if that's possible.

If these schematics are not readable I can email them to you.

Pete

Well here's the link:
http://home.t-online.de/home/O_Scholz/sub.html

I'm not sure you need it now. I think you're right, using the Fiero amp will bypass/override the features built into your unit. Also, it's only a 20 watt amp so it's pretty limited on output anyway. I think your best bet would be to get a small amp that can be wired for mono (bridged) output.

It would be fairly easy to hook up; RCA wires from your unit, power and ground, Power Ant to turn it on and 2 wires to the Fiero sub. I don't think you can use the Fiero slider, but I think you can control the output level from the radio anyway.

Also, you should get a replacement speaker from Rodney Dickman. It's rated at 60W. Since the Fiero amp is 20W I doubt the factory speaker is much more than that.

Rodney's speaker is an 8 ohm unit. Amps should be rated for 'x' watts at some ohm value (usually 2 or 4) when bridged. You need to take the 8 ohm speaker into consideration when sizing the amp. Maybe someone else here can help with the math to figure out the right size amp to drive a 60W, 8 ohm speaker.

quote Originally posted by DRH: Did you get the wiring also? The factory amp is wired into all 4 speaker outputs, you don't need your separate sub output. It's actually a Y type harness that goes between the radio and the existing speaker wiring with another set of wires running to the amp. The only real trick to it is powering the amp. The GM radio powers the amp when it's turned on. The power is supplied thru 2 pink wires, both going to the same terminal at the radio end. Most aftermarket units don't have a power output that will supply enough current. The only thing they have is the power ant. lead which will drive a relay, but not an amp. I rigged up a relay on mine. I've heard of others just wiring the amp power to an Acc wire. I've also seen where someone separated the 2 pink wires and hooked one to Acc power and the other to the Power Ant. Inside the amp one is supplying power and the other is just switching it on with an internal relay. The only trick is figuring out which is which. I had a link to an article on it which I can't seem to find right now. If I do I'll post it here.

This is exactly what I was going to say. I wired up a relay for the sub and the radio that latches to give me a "retained accessory power" feature. The radio stays on after the car is shut off, until the driver's door is opened. I added that in both my Fieros.

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If you find my advice useful, then please give me a positive rating, thanks...

Cliff;

If you need a new speaker let me know and I'll get one in the mail ASAP N/C.

Rodney Dickman www.rodneydickman.com

quote Originally posted by Rodney: Cliff; If you need a new speaker let me know and I'll get one in the mail ASAP N/C www.rodneydickman.com

Thanks for the offer, but I just checked the speaker and it's still undamaged and working perfectly.

Only problem is that I don't have the wiring. Not really a problem but more a hassle to make the wiring myself. Now the only thing I'm still not sure about is how I will wire it.

My headunit has a subwoofer out which are in fact two cinch plugs (red and white) and they are both labeled "subwoofer out or non-fading out". I guess that means it's not amplified. I can wire the subwoofer the "stock" way by wiring it into the 4 speaker outputs. The only disadvantage is that I miss out on all subwoofer settings (crossover, normal/reverse, etc) on my headunit. Plus, I'm not sure the stock sub-amp can handle the 4x45 Watt output.

I can also hook it up the "official" way by getting a new subwoofer amp. I can use all the extras on my unit then, but I don't have the overhead slider.

Choices, choices.

Just a small update to let you know I installed the subwoofer system today. I connected it "the stock way", so using the speaker outputs of my headunit, the stock amp and the overhead slider. I ended up connecting only 1 speaker output (instead of 4) because I think the power output of my headunit is too high for the amp (connecting a 2nd speaker distorted the sound).

I must say I was quite impressed with the sound for such a small (and old) speaker.

Everything works, including the overhead slider.

Thats great, I am going to buy a small amp and hook up my sub with it. I have the stock amp but after I hooked up 2 speaker inputs it sounded bad so I am just going to replace the amp and then I will probably have to get a new speaker
Glad yours is working

[This message has been edited by Jake_Dragon (edited 02-21-2003).]