ero1220 Posted August 18, 2004 Report Share Posted August 18, 2004 I'm not very good with car audio setups, and when I say not very good I mean I know next to nothing. How exactly would I wire in a seperate amp powering two 10" subs I have in a box in the trunk? I have all of the equipment and wiring, and I understand what is needed, but I'm no genius electrician. My plan is to have the amp and subs in the trunk and have a seperate control (simple on/off) up front for them. This is a project I had an old friend do for me in my 93 STS, but I haven't spoken with him in years and I know someone here will be able to provide some help. Link to comment Share on other sites More sharing options...
Jeff Wilson Posted August 19, 2004 Report Share Posted August 19, 2004 I have been thinking about adding a new 12" subwoofer too I know I could do it but becasue of Caddilac's extensive electrical system I will leave it to the boys at the stereo shop. A reputable stereo shop should charge you no more than 4 hrs labour. Spend the money to hook it up the right way. Link to comment Share on other sites More sharing options...
phat albert Posted August 19, 2004 Report Share Posted August 19, 2004 i bought two really high end 12" subs with the appropriate amp to run them, i do not know how they installed it but i know they somehow spliced into the stock stereo, it sounded like crap the bass pumped like crazy and it was really loud but i got an electrical interference with every thing the car did like the engine RPM went throught the subs turn signals the antena going up and down,it was not reall noticable at first but it got progressivly worse forcing me to just take them out,they are now in my semi, hopefully your installer knows what they are doing better then the guys at AVU in guildford b.c. and remember get something louder than you want that sealed trunk sure keeps in alot of the noise. good luck Link to comment Share on other sites More sharing options...
bigfoo Posted August 19, 2004 Report Share Posted August 19, 2004 I'm planning on doing the same to mine.. Really I think just replacing the stock subwoofer and maybe getting a bigger amp might satisfy me without a box.. but i'm not sure.. It's real easy to hook up.. You have to take the back seat out to get to the amp (at least on my 99) and I don't mean just the bottom i mean the entire seat back. Link to comment Share on other sites More sharing options...
cad98 Posted August 19, 2004 Report Share Posted August 19, 2004 Be carefull 12" sub is a free air sub if you go with a regular sub you will have to build a box. Also if you hook a amp up to Bose you will blow something bose runs at 1-2 omh. Link to comment Share on other sites More sharing options...
Willie Hank Posted August 19, 2004 Report Share Posted August 19, 2004 Be carefull 12" sub is a free air sub if you go with a regular sub you will have to build a box. Also if you hook a amp up to Bose you will blow something bose runs at 1-2 omh. Your proabably talking about the speakers at 1-2 ohm, not really germane to a signal coming from the head unit. Link to comment Share on other sites More sharing options...
Willie Hank Posted August 19, 2004 Report Share Posted August 19, 2004 Your best bet would be to engage someone with experience, to be sure. I'm a little skiddish about giving advice abouts stereos when I am unsure of the recipients knowledge. However, here is one approach to explore. Some power amplifiers have "high inputs", that is, they will take an input from a powered signal coming from a head unit, and they will also have "low inputs" or "pre-ins" from a pre-amplified signal coming from the "pre-outs" from a head unit. I do not know anything about the Bose system, other than I have read a power amplifier is resident on the speakers. If that is the case, then more than likely the signal coming from the amplifier will be a pre-amplified signal. That being the case, you can tap right off your rear speakers, to the power amplifier. However, you must know this in advance. If it is an amplified signal and you tap into the low inputs, you will be amplifiying an amplified signal and could potentially overdrive your power amp and blow your speakers (the latter would probably not occurr, as woofers are pretty resilient. If it is a powered signal, you can tap into your high inputs on the amp (if they exist), or buy some turn-down pot.s at a car stereop shop, that will effectively turn the amplified signal into a pre-amplified signal. If you bought the right type of amp, you bought a bridgable amp, which will mix the left side signal with the right side signal, to produce a mono signal output to your sub-woofers. You will need to tap off your switched wire to the head unit (usually blue wire, 12V), and run a SPST toggle switch in series at the dash, prior to connecting it to the 12V switched wire on the power amp. This will allow you to cut the subwoofer amp out, if you do not want to use it. There are many more things to consider, such as right-sizing the subwoofers with the amplfier, the impedance of the speakers and stability of the amp at those impedances, which will determine whether you run the sub-woofers in series or in a parallel. Hoepfully you did this when you spec.ed the amp and woofers. If you know someone who has expereince with this, I would employ their knowledge. Link to comment Share on other sites More sharing options...
vantasticdude Posted August 19, 2004 Report Share Posted August 19, 2004 I'm not positive but I think the original Bose sub is still at 4 ohm which should allow any new sub ................ adding a more powerful amp is a different story altogether . You could always hook up the old way ... ie .. low level outputs off the main speakers to a low level input of an aftermarket amp yada . Link to comment Share on other sites More sharing options...
Jeff Wilson Posted August 20, 2004 Report Share Posted August 20, 2004 Find a reputable stereo shop that can handle this type of project as I have heard that the head unit communicates with the computer and the alarm in the car. More reason to seek out a good stereo shop. Let us know what you going to do. Link to comment Share on other sites More sharing options...
Willie Hank Posted August 20, 2004 Report Share Posted August 20, 2004 You could always hook up the old way ... ie .. low level outputs off the main speakers to a low level input of an aftermarket amp yada . So the Bose subwoofer is a powered subwoofer? Link to comment Share on other sites More sharing options...
Willie Hank Posted August 20, 2004 Report Share Posted August 20, 2004 Find a reputable stereo shop that can handle this type of project as I have heard that the head unit communicates with the computer and the alarm in the car. More reason to seek out a good stereo shop. Let us know what you going to do. I would be hard pressed to believe the car computer "monitors" how a pre-out signal is being utilized. Link to comment Share on other sites More sharing options...
67coupedeville Posted August 20, 2004 Report Share Posted August 20, 2004 My buddy had just put two 10" subs into his factory stereo in his 2000 Chevy Truck. What he did was bought this splicer box that brings in the wires from a speaker and runs four wires out, two back to the factory head unit and two to the amp for the subs. The thing is with his is that there is no filter for the words from the speaker and you can hear words coming through the subs. It was a relativly easy install but kinda shotty at the same time. The box for splitting the speaker wire into 4 was I think $20 CDN from Radio Shack. I guess if you have subs in the trunk rather than in the cab of a truck, you would not be able to hear the treble coming through the subs . Spence Link to comment Share on other sites More sharing options...
Jeff Wilson Posted August 20, 2004 Report Share Posted August 20, 2004 I would be hard pressed to believe the car computer "monitors" how a pre-out signal is being utilized. I didn't say that the computer "monitors" a pre-out I said the car's computer communicates with the head unit. As to what it exactly commmunicates with I am not sure, however my guess is a car phone. Link to comment Share on other sites More sharing options...
Marika Posted August 20, 2004 Report Share Posted August 20, 2004 If you know nothing about it don't do it. The police and fire departments are reporting a lot of cars catching fire because of overheating wires and amps in cars do to the installation of custom sound systems or add-ons to existing systems. I would suspect a lot of these fires are caused by do-it-yourselfers. Leave it to a professional. If you really want to make people safe drivers again then simply remove all the safety features from cars. No more seat belts, ABS brakes, traction control, air bags or stability control. No more anything. You'll see how quickly people will slow down and once again learn to drive like "normal" humans. Link to comment Share on other sites More sharing options...
CaddyChris Posted August 21, 2004 Report Share Posted August 21, 2004 Ero, Sorry I didnt get back to your PM. This is how you do it. Assuming the brains of the headunit are still in the back right corner of the trunk by the power antenna, which I assume they are? If not please correct me someone, because all I have is a 94. You need to get the cadillac shop manual for 99, find out where it diagrams the reciever. On the diagram you will see what color wires are going out to what speakers. This is before they are amplified at all. This is the signal you want to get in order to have clean bass. This is called the "low level" output. You need to find the 4 wires, going to Right Rear and Left Rear speakers. There will be a + and - for each. Get yourself a pair of "dykes" or strippers and carefully splice into the positive of each wire without cutting it. You may also try a razor blade to skim off the insulation. Get about 1/4 inch of wire exposed. Once you do that on both +s go to radio shack and get 2 good RCA cables with two male ends on each side. Cut the one end off and strip the insulation around the wire that runs through the middle of the RCA cable, this is your +, Also, take note that the amplifier should have RCA plugs, if not, you should get a new amp. Anyways, around the outisde of the + there will be a braided type of wire going around the outside, this is -, get enough of both wires exposed, you will have to twist the braided - to make it all 1 wire. Now, splice the positive ( center of RCA cable) right onto that 1/4 inch section, you can weld it, but i would just wrap it around the 1/4 inch section a few times, make sure you electrical tape it. Do the same with the other RCA cable. Now, as far as the - side, when I hooked the -'s up to the -'s coming off the reciever, I got all kinds of feedback, w/ the engine rpms, it sounded bad, I simply took both -'s from both the left and right channel, (after you splice the +'s into the +'s) and sent them to a ground. The subs pick up the channel from the + side. I wouldnt even bother to try to hook the -'s up to the -'s coming off the reciever. Now, you are all set for your speaker signal, you need to run the power cable back from the battery, make sure you put a fuse within 2 ft of the battery, and also , splice into a hot on ignition by the power antenna, this can be accomplished with a test light, seeing what is hot on ignition. YOu can just use speaker wire for this, it will go to the remote turn on on the amplifier. That should be about it. If you need anything else, I'll check back tommorow or send me a PM. Chris Christopher Petro 94 sts 67 coupe de Ville Link to comment Share on other sites More sharing options...
ero1220 Posted August 22, 2004 Author Report Share Posted August 22, 2004 I ended up doing it myself, I followed cpetro's directions. I knew this was something I'd be able to tackle with a little bit of direction. I know enough about fuses and wiring to make sure I won't be starting any fires, I mean I do a little electrical work on the side as part of a shopping plaza maintenance job, and I've wired enough stuff into an STS to know a little bit about where things are (CD changer and hands free phone in a 93 and hands free phone in a 2000). I'm just not familiar with speaker input/output, pos/neg etc etc. or car audio setups in general. Thanks guys. Link to comment Share on other sites More sharing options...
Willie Hank Posted August 23, 2004 Report Share Posted August 23, 2004 Do what you want, but if you get noise, it might be because you ran speaker (-) to ground,...not a good idea. A noise-free stereo installation starts with "isolating" the signal as much as possible. Also, taping wire connections is not a good idea either, always solder to eliminate intermittent connections and thus, noise. Link to comment Share on other sites More sharing options...
Willie Hank Posted August 23, 2004 Report Share Posted August 23, 2004 My buddy had just put two 10" subs into his factory stereo in his 2000 Chevy Truck. What he did was bought this splicer box that brings in the wires from a speaker and runs four wires out, two back to the factory head unit and two to the amp for the subs. The thing is with his is that there is no filter for the words from the speaker and you can hear words coming through the subs. It was a relativly easy install but kinda shotty at the same time. The box for splitting the speaker wire into 4 was I think $20 CDN from Radio Shack. I guess if you have subs in the trunk rather than in the cab of a truck, you would not be able to hear the treble coming through the subs . Spence I am surprised his amplifier didn't have a low pass filter to cut out the "highs". Most amps come with high pass and low pass settings. If he is not cutting out frequencies above 150 hz, he is getting the whole spectrum of sound, and his woofer will not respond well to the low frequencies because it is trying to reproduce all frequencies. For deep base response, some "thumpers" will cut out signals above 75 hz. Basically, he doesn't have a woofer, he has a very large 1-way speaker. Link to comment Share on other sites More sharing options...
CaddyChris Posted August 23, 2004 Report Share Posted August 23, 2004 I forgot to mention that i have a monoblock amplifier, which would be the best to use for this application. It takes the L and R channel and makes it one. These types of amps are designed for subs and an application like we are discussing. This amp ignores all the high frequencies automatically. As far as Ero's amp, who knows, if it has high pass and low pass, obviously put it on low pass. Additionally, Willie, when I hooked my negetive leads to the negetive coming off the reciever, there was all kinds of horrible feedback w/ engine rpm). Where would you suggest, other than to a ground ( such as the one on the power antenna) to put them? Mine are grounded and the bass is very clean, no interference at all. Ero, please comment on how yours sounds. Thanks. Chris Christopher Petro 94 sts 67 coupe de Ville Link to comment Share on other sites More sharing options...
Willie Hank Posted August 23, 2004 Report Share Posted August 23, 2004 Additionally, Willie, when I hooked my negetive leads to the negetive coming off the reciever, there was all kinds of horrible feedback w/ engine rpm). Where would you suggest, other than to a ground ( such as the one on the power antenna) to put them? Mine are grounded and the bass is very clean, no interference at all. Well, "the proof is in the pudding", if you got better sound grounding out the speaker (-), then I agree, do what yields the best results. Car manufacturers stopped the practice of grounding the speaker negative years ago, I cannot comment why your getting noise from the head unit (-),... sometimes experimentation yields unpredictable results, ...as you found. Interesting information ..... Link to comment Share on other sites More sharing options...
ero1220 Posted August 25, 2004 Author Report Share Posted August 25, 2004 Ok, so here it is... I pretty much followed cpetro's directions by applying them to the way the newer model is configured. I got lots of feedback/never sounded right so I just trashed the amp because it was a piece of garbage anyway. What do you guys think about a direct connect into the wiring for the Bose 12"? The wires are exposed right there and I figure that either the head unit is definitely powerful enough to support two (small) 10's or there is a pre-amp between the 12" and the head-unit which would definitely ramp it up enough to support them. I haven't traced any wires yet because I'm working mostly on my phone system... I can't get the thing to work on ignition. When the car is off the battery in the phone will charge, but it cuts out when accessory comes on or when I fire it up. I've been trying different fuses, battery c/dc, phone on/off. It's odd. This is something I've installed in four different Cadillacs and once before in this car. Link to comment Share on other sites More sharing options...
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