oryxbikeboy

Hello, I just joined this forum so I can get some help with putting an amp and sub into a factory 2002 Rendezvous.
The Rendezvous has the premium sound package with an amp and rear subs.
My son has a JBL BP300.1 amp and an 8 inch sub that he would like to put in this Buick.
I am wondering if the best thing to do would be to disconnect the two factory subs and use their power wires from the factory amp as the input into the JBL amp and then to his 8 inch sub?
Would it be okay to connect the left and right sub wires together or should I just use either the left or right alone?
By the way, his 8 inch sub is 125 rms and 4 ohms.
Thanks, I appreciate any help I can get.
Craig

gramser57

iTrader: (1)

Line out converter and tap it into the rear speakers. Run a power wire from the front battery to the amp, find a viable source for a ground, tap a remote wire from the ignition to the amp and it will be good to go.

oryxbikeboy

Thanks gramser57 ,
Line out converter and tap it into the rear speakers.
I'm not really sure what this means. Are you saying that I should leave the factory speakers connected and just run a line from each of them to the amp input and then to the 8 inch sub?

gramser57

iTrader: (1)

oryxbikeboy

Thank you gramser57.
That is very clear. I will try this in the next day or two and post my results.
I have a couple of more things that are not clear to me. Reading the amp manual it is clear how to adjust the input-sensitivity LEVEL
control but could you let me know how to set the frequency and bass boost controls. This is what the manual says: These amplifiers are designed to
drive subwoofers. Consequently, the
electronic crossover is a 12dB/oct.
low-pass filter which can be set at any
frequency between 32Hz and 320Hz.
The bass boost control will provide up
to 6dB of boost at 50Hz.
Thanks for your help, Craig

gramser57

iTrader: (1)

When setting up the equipment make sure everything is set to 0 and head unit EQ is flat.

On the amp keep the bass boost to 0, adding bass boost will create distortion which you don't want.

Set the Low Pass Filter between the 10 o'clock and 11 o'clock and it will be close to 80hz on that amp. I am not sure what kind of enclosure you have but you can later set the LPF higher if its a sealed setup to give you more usable bandwidth.

Now play a song that is 128kbps (that is equal to CD quality) to ensure its high quality and it also helps if the song has a constant bassline. Turn the volume up until you notice the speakers are starting to distort then back it down a notch, usually 75-80% of the max volume. Now keep the volume on that level and slowly turn the gain up on the amp, listen to the sub for mechanical noise or notice if starts to sounds sloppy then back it down a notch.

That is the easiest way to gain match an amp and usually the safest way, just make sure not to turn the bass boost up on the amp or turn the bass up on the headunits EQ.

Cheers

That is the easiest way to gain match an amp.

zoomer

iTrader: (3)

I think there is a lack of information here. Basically you don't know if the main speakers have a high pass on them. If they do, then tapping off the rears will not give you any bass.
You could try various setups tapping off the fronts, rears, or sub.
You could also disconnect the sub to see if there is much bass coming out of the mains. personally I would go with tapping off the sub outputs. I would not connect them together as you don't know if they have their own amps or both connected to a single amp. If they each have their own amp and you connect them together you are shorting out the amps! You can test this by seeing if there is zero ohms between the 2 sub positives, and the 2 negatives. My bet is that they have separate amps.
You can use the sub power wire as a remote on for your sub amp.

IT Hz

iTrader: (1)

If your using a high level adapter, and the factory system has a factory subwoofer that is where you tie in your high level input. If you tie into a speaker lead say for example the rear speaker leads and you want to fade your music more to the front (for whatever reason), the unfortunate thing is your sub performance is going to be affected because of the fading. So use your factory sub leads as your high level source input.