Car sub Woofer

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first, the channels need to be summed (mixed) then sent to an amplifier.
Usually behind the 'radio' there are 2 RCA plugs available, and they are labeled
'pre out'. To overcome the absence ot those outlets , amplifiers have a
'high level' input , which reduces the signal with a resistor net to line level, then process the signal as usual : mix R&L ,lowpass>amplifier>speaker
In the past, woofers with a double voice coil were used with a coil each powered by each channel, but it's a solution not used nowadays.
Well, you should specify if you're referring to a woofer or a subwoofer, since
98 % of woofers have a single voice coil, and subwoofers ...well, it's just
for their intense use that DVC has some sense, since it dissipates the heat double, and as a plus the two VC may be paralleled to have more 'gain' (the impedance Z halves, so the amplifier 'sees' a lower load and is capable to pump more current...the negative side is that distortion doubles as also heat, which is not good with unsurveilled electronics such in car environment)
Then, you have to send to the loudspeaker only the range of frequencies that
it is supposed to work with. So to correctly drive a ( single) subwoofer the amplifier needs to be mono and needs an electronic filter ( crossover) to process the signal before entering the amplifier. Otherwise you still need to
filter or EQ a signal before sending it to the speakers, which is done with the (power) passive crossover, after the amplifier, but you'd need some inductors/coils/bobbins ( and also capacitors for correct filter slope) that are
humongous sized and not ready available for your project.
Too many words!:p
What radio is that?
Make and model.
Have you also install a separate power amplifier?
Some radios have build in crossovers that work with both the pre-outs and the build in amplifiers.. I am sure your answer is in the owners manual.
Post the make and model and I can check it out.

One more thing, unlike home or pro subs many car subwoofers come with a dual voice coil.
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Let me google that for you :D
98 to 2001 GS 300/400 Subwoofer Upgrade
In case somebody is interested I like to share that modification. It made a HUGE difference.

The stock stereo in my GS300 was fine as far as clarity of the mid and high parts of the music spectrum. The bass, however, was weak.

I just finished replacing the 10" subwoofer located on the rear deck with a new one and I added a separate amp to power it.

Now I can shake the mirror and feel the "thumps" in the seat !

I bought a KICKER Comp 07C104 10 Inch sub. the reason I picked that one if because it works well in free air ( the trunk ) as opposed to being in a small enclosure. The Amp I bought is the : Profile HA700M 350 watts at 2 Ohms.

I am sure there are other models that will fit as well

The trick is to install the sub. You have to remove the rear seats to get to it. It is not difficult if you know how .........

First, sit in the back seat and grab the front of the seat from underneath, lift until it pops out and remove the seat bottom.

Now you see 7 bolts that hold the vertical back seat. Some are 12 mm others are 14 mm. Unscrew them all. Remove the head rests. Now lift the leather flaps under the headrests and unscrew the two 12 mm screws there. Move the vertical seat forward ( keep seat belts attached to the the top ).

Now you can lift the rear deck and unscrew the existing sub.

To install the new one ( with different bolt pattern ) you might have to use some plywood to trace the pattern of new sub and securely bolt it on said plywood. Use some foam gasket material between sub and wood to eliminate vibrations. Now check out the screw pattern in the deck and use the same bolts to install your plywood with new sub on it into existing spot. Again, use foam gasket material to dampen potential vibrations.

This was the hard part.

Proceed with re-intalling the seats and you are done for the sub install.

The amp. is in my trunk and I use the existing 2 wires from the Lexus stereo to power the HI input of the Amp. Every other connection is standard:

12 Volt from battery ( fused)

12 V (ignition Only )


2 wires to Hi Input

2 wires to the new sub.

Adjust cross over frequency to fit your style and VOILA !!

Enjoy window rattling bass that can potentially frighten women and small children

If you have any question, send me an IM I will be glad to help
I have a Lexus 2001 GS300. I have installed a new radio which has one left and one right woofer output. How do I connect the out puts to one Woofer?

I have a 1997 Toyota Soarer (which would be the 1998 Lexus SC300) with the same engine as your car (and incidentally have your model wheels on my car:)).

Many Soarers come with Premium Stereo which includes a subwoofer on the parcel shelf, like yours. They have a separate amp under the carpet in the boot (trunk) although mine didn't as more basic stereo. I tried a 2nd hand Soarer subwoofer (after mounting and wiring an amp in the boot) but they're all quite old and the surrounds are hard (my woofers collapsed altogether- the parcel shelf is an inimical environment for a driver:mad:) so mounted a cheap 10" Philips unit instead. In any case the std Soarer 10" subs (whether EAS or Nakamichi[rare]) are 2Ohm, not good for most aftermarket amps).

The tutorial posted above looks on the money- a shallow, "free air" woofer is apparently the best bet for this application. Mine most certainly isn't "shallow" and I have only about 2cm clearance between bottom of driver and fuel sender unit's outlet. I may change to an 8" sub later, with an adaptor ring. The Philips unit sounds fine, it'll transmit bass (and vibrations) all through the car!

Oh, I have changed head unit to a Sony single DIN unit. Original unit was OK but ran extremely hot (even with the tiny wattage std speakers) which I thought was not good for my CDs, especially in our hot climate. Have never used the CD player in the Sony unit though- it has a USB input.
It is highly probably that the factory radio sends two channels to the factory subwoofer amp, which mixes the channels into 1 mono channel, and powers the sub.

So you need to connect your radio's "woofer" outputs to the factory amp left and right inputs. But really to help, we need:
- Make/model of the radio
- Picture of the factory sub amp inputs, if possible.

OR, you could try calling Crutchfield to ask. There is a decent chance they have a wiring harness adaptor that will do just what you need. If not, perhaps Metra or Scosche might.
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