alright, so I'm installing my amp/sub this weekend, and maybe into next week if i can't get all of this figured out by sunday. here's what i've got to install:

1. pioneer premiere 12" sub going in a sealed enclosure
2. profile ap700m amp w/ 8-guage wiring kit
3. stock head unit

my friend/really good car tech guy is helping me install it. he's done many of these installations before, and says that i can do it with a stock HU. what i've heard from you guys is that there are two options: 1. buy an RCA headunit mod on eBay so the headunit will be able to support RCA connections or 2. splice the rear speaker wires and get the RCAs that way.

here are my questions (try to answer objectively):

1. im leaning towards splicing the rear speaker wires. if i do this *CORRECTLY*, will my sound quality suffer a lot?

2. we really want to avoid drilling through the firewall. does anyone have any pics/knowledge of where suitable holes already are?

3. we also need to have a way of turning off the amplifier so my battery is not getting robbed of power 24/7. how would we go about this with the stock head unit? my amp has a remote gain control, but that wouldnt really do anything here would it?

thanks everyone for the answers. i really appreciate it. this forum is the best.

-matt

 

1. I think the headunit RCA mod you're talking about is a line out converter. It will be fine.

2. You can fit the wire through the main grommet going through the firewall. It's on the driver's side near the steering stem (I think).

3. Are you sure your friend is a "really good car tech guy"? It's pretty standard to know that amps need to get a signal to turn on, hence the remote wire. I'm not trying to insult your friend or anything, but it's pretty standard knowledge. Just find a wire that is turned on when the key is on. Not sure which one because I haven't installed an amp in the tC yet, but search and you should find it.

 

haha well... he told me what we needed, but 1. i forgot what it was already (yeah i'm the dope of the group) and 2. he wanted me to double check on the forum since we're surrounded by really smart scion junkies.

thanks for the response though! good help!

 

I just wanted to make sure. I wouldn't trust someone to install my system if they don't know what a remote wire does.

It shouldn't really be that hard. It's a pretty straight forward install, especially after you get your car apart. Take your time, double check your connections, and make sure you disconnect your battery terminal before you start hooking anything up.

 

1. just make sure your amp has speaker level inputs. if you want to do it safely i suggest getting a Line Out Converter cause it will make things easier later if you want to change your amp if your amp doesnt have speaker level ins.

2. What i did to run my power into my car, if you trace the handle in which you open your hood from, it leads into a grommet in the foot area near your pedals. simply make a incision (sorry too much nip/tuck) and then run the power to the engine bay from there. the cable will endup behind the driverside strut tower (im not too sure of the exact name) so it will be a bit hidden, and you may need some small hands to get it out, but its alot easier than drilling through the firewall imo.

3. Fortunately the stock scion tC deck has a remote, which isnt to common. coming from the harness it is the blue wire on the bigger connector. just tapsplice a remote wire off that and run it to your amps remote input.

also personally i would run 4awg instead of 8awg. im only running 400 watts and i still run 4awg just for safety. im not exactly too sure how safe 700watts in 8awg is, but id use 4awg :D.

also heres a page that may help you alot in the long run. just search for wire diagram, so you know which stuff to splice the LOC off. and all this is off the bigger connector behind the deck

http://home.cfl.rr.com/icdedppl/faq.html#c12

GOOD LUCK! :D

 

and if you need help about grounding points i can tell you where and how to run stuff too. just pm me :D

 

thanks ADRdesignCo, good info

 

bump

 

no prob man. any results?

 

well we're not actually tackling it till the weekend (most likely sunday). BUT i was talking to my dad, who's pretty electrically inclined, and he brought up a question that i couldn't answer... take a look and let me know if it makes any sense:

when i told him about splicing the rear speaker wires and getting some RCA connections, he asked what kind of wires are being worked on. if they are the "power wires", hooking them up to an external amp would cause some major issues because the lines would be too powerful for the amp (distortion or damage would ensue). so what type of rear speaker wires are we splicing here?

i dont know... my friend who's helping me with the install has basically the same setup in his camry. all he has different is an aftermarket HU (which is a lot...). His 1 12" is LOUD. It sounds better than a lot of dual 12's ive heard. that's how i want mine to sound - if my SQ is going to suffer by doing this whole rear speaker wire procedure, i might just suck it up and wait to buy an aftermarket headunit.

 

and by the way, my amp does have speaker level inputs

 

The line out connector splices into the rear speaker wires. No power runs through these wires. All you are doing is taking the stereo signal and converting it so that instead of speaker wire, you have a set of RCA cables, which are in turn hooked into your amp.

I'm not sure on the benefits of line out connectors versus speaker level inputs. Hopefully someone else can answer that question.

 

thanks for the response, that clears some stuff up. now i think i'm getting close to a decent understanding. anyone care to input on the above quote? thanks in advance!

 

my amp right now has speaker level inputs alongside RCA inputs. when i had that original set up (amp + sub + Stock HU) i bought a line out converter. the main reason i went with this is because the wires that i couldve used the speaker level inputs that came with the amp were really short (less than 1ft) and 1foot is far from any of the speakers to splice off (my amp is in my trunk). secondly i went with the LOC instead is because if i wanted to (still do) upgrade my amp, not many amps have speaker level inputs. having those RCAs allow me to swap out any amp i wanna put in there easily. and if you were to truly splice off the rear speakers from anywhere near the actuall speakers themselves it will be a pain cause you literally have to rip our your whole back seat to gain access to them. thats why i suggest splicing the LOC into the harness behind the deck and run the 2 RCAs to my amp. in short, using the LOC is alot easier, just as efficient, and easy to upgrade the amp later down the line to ANY amp that i would want. :D.

about bumping your sub, use the SSP trick, set it to xB Feel. and set your amp accordingly to make it feel the way you want it. i had it on that setting before and i loved it. i actually kept my bass at -4 (sounds little but it was alot) and i was able to set off alarms with only 400w. but set it to the way you want it to sound, but always set it within safety (dont push your amp's gain to its max, etc) also for the safety of your sub make sure you set your LPF too, dont wanna throw in frequencies that your sub cant handle.

but to answer your question, using the LOC makes things alot easier to install, and makes everything just as good :D. hope this helps.

 

okay guys so i was researching stuff on my amp and this is what i found on crutchfield:

High-to-Low Level Converter: The amp is equipped with an external high (speaker) level to low (line) level converter to allow you to connect the amplifier to a receiver or factory radio without RCA preamp outputs. After splicing the receiver's speaker wires to the converter's speaker wires, you can simply plug the converter into the amp's RCA preamp input.

does this mean that if i splice the speaker wires, i dont need any other parts? everything i need is right there on the amp?

 

i just looked your amp up on crutchfield. by the looks of it you don't have speaker level inputs, you only have line level inputs (the RCAs). as for the converter you mention it has, i didnt see it on the page, but by the description you gave it sounds like that is a LOC.

 

hey, were you looking at the right one? here are specs straight from my amps page on crutchfield:

Details:

» mono subwoofer amplifier
» 220 watts RMS x 1 at 4 ohms (350 watts RMS x 1 at 2 ohms)
» MOSFET power supply
» remote-mount level control with 16-foot cable included
» selectable bass boost (0-12 dB) at 45 Hz
» variable low-pass filter (50-250 Hz, 12 dB/octave)
» subsonic filter (20-50 Hz, 12 dB/octave)
» preamp- and speaker-level inputs
» preamp outputs
» fuse rating: 20A x 2
» 4-gauge power and ground leads recommended — wiring and hardware not included with amplifier
» 11-5/16"W x 2-1/16"H x 10-1/4"D
» warranty: 3 years

and to see the other part about the included converter, you had to click the tab that said "Crutchfield Hands-On Research." It was there i think. but anyways, im just clarifying, i dont want to get into installation and find out something different. thanks!

 

the only reason i said you dont have them, was because i was looking at the pictures. speaker level inputs are usually just bare wires coming out of the amp, that you would splice. wheni was looking at the picture, i did not see any speaker level in terminals, only RCA ones.

however i did see the page with the line out converter, which i found very convienient that you wont have to buy another. my best guess for this is that they say it has speaker level inputs because it comes with the LOC. personally id use the LOC either way even if my amp had speaker level input. but thats just personal preference

 

alright! thanks ADRdesign, you've been a big help. I'm going over to my friends house either today or tomorrow to see what we can do in the way of install this weekend. i'll keep you all updated and post pics as we work.