Amp/Sub Setup

[pro956]

You would have to keep the gains down a bit, but your amp won't be stressing so that's a good thing. Headroom is always good.

people don't seem to understand that concept for some reason...
i ALWAYS use an amp that will overpower a sub at full output.

everyone should try it out, if you have an okay ear for sound quality, you'll be happy you did it

[WJN333]

Ok so I ordered the Image Dynamics ID12 v.3 D2! Im gonna get most of the wiring in this weekend, so when it shows up I can put it in right away.

Thanks
Bill

[WJN333]

ok so i have the car dismantled, two projects at once. I found the small grey wire in the wiring harness, very thin and has a silver band on it, just wanted to confirm that this is the ACC turn on lead. Also I need to run the amp power cable so the fuse is next to the amp in the trunk, not the batt, is this a problem?

[cam2Xrunner]

To test that wire to see if it is the acc turn on lead, cut it in half when the car is on If the radio turns off you got it lol

But I'm pretty sure that is the one, did you see any other thin grey wires?

The inline fuse on the power wire is supposed to be connected less than 18 " from the battery, in the engine compartment.

[WJN333]

There was only one other wire that could have been it. Im not sure if that wire was grey, it had some extra, loose, grey, sheilding around it. Figured it was the one that was actually grey. got that wire in. Any idea what kind of juice is running through that wire? Volts? Amps?

The reason I asked about the power wire is that there isn't a good spot to Mount, yeah the one that i got mounts, the fuse holder in the engine compartment. Where its out of the way, but has reasonalbe access. I have the 4 cylinder (fyi). Easy to mount to the rear seat, plus the crimp on that end will fit into the amp, the one supplied for the other end will not. Just seemed easier to run it the other way. No worries, havent run the cable yet, ill figure it out tommarrow, was having a little trouble with that one today.

BTW: thanks for the tip on the grommet next to the master cylinder, should work beautifully.

[WJN333]

Got the amp mounted today. Plus the ground cable and the power cable, the right way. Went and bought a better fuse holder, cable, crimps... powered the amp briefly with no inputs/outputs and checked the acc lead. Checked out, so did the switch idea. Just thought Id let you all know. Time for sleep.

[WJN333]

Fine tuning time:

I set the amp on stereo to activate the brided mode, the bass boost off for now, and the filter on LPF.

I adjusted the amp's LPF frequency knob to be whithin the specs on the sub (generally).

There is another knob next to it that says "Input sensitivity" where should I set that knob? Increments are (Min) 5, 4, 3, 2, 1, 0.5, 0.3, 0.2 (Max). Is this my controll over gain?

Sound right??

[cam2Xrunner]

Yes that is your gain. You will want to match that to your headunit's voltage on the preouts.
http://www.jlaudio.com/tutorials/Input_ ... ivity.html

http://forum.sounddomain.com/ubb/ultima ... 2;t=030419

Also where do you have the crossover set to?

[WJN333]

Crossover being the LPF on the amp? If so i have it set from 50 to just below 150 Hz. cant go any lower than 50 with this amp, sub will only go to 150.

You have a saved mp3 or wave file you could send me of that sine wave recorded at 0db? I have a digital multimeter.

I have to get one more @#$% part! I need some sort of RCA to Speaker level input jack converter, other than that its all in. De-activated for the time being. Good thing to, Im tired of rolling the mini-van.

[cam2Xrunner]

N-85V from http://www.davidnavone.com/adaptor_products.htm will work perfect.

Here's your downloads.
http://www.realmofexcursion.com/downloads.htm

[WJN333]

Got the download, Thank you very much.

First, I dont understand what the N-85V component is for??? I thought the amp was acting as the crossover as well?

Second, my "P" power in those equations should be 250? the RMS power rating for the sub?

Amp: Bridged (4 Ohms)(1kHz, 0.8% THD)..............460 Watts x 1

Sub: 250W RMS, 500W Peak

[WJN333]

Ok so i think i got this.....please check

If i want my final output power to be 250w (P).....

And it is a 4 ohm system (R)

Using what I saw at the JL site for bridged systems we divide the R by 2, then double the value we get for V.

V=(PR)^(1/2)
V=(250x2)^(1/2)
V=(500)^(1/2)
V=22.36 Double that and we get 44.72

If i meter across the bridged channels with the input sensitivity at min and get a value too high, should i decrease the LPF range to make up the difference? and currently my RCA jacks are run into the RCA ports that say "Line In", from the unit that branches off the rear speakers. The "Speaker level input" is some square port with pins inside. Should i be running to that input?

Please Help. Pleeeease!

[cam2Xrunner]

The N-85V takes the speaker wire from one of the rear speakers and coverts it to an RCA output.

Or you can just wire the speaker into the amps speaker level inputs.(the square thing)

If you are not sure on the gain setting, just start off with it at minimum, then turn it up until you hear it starting to clip. Then turn it down some. The main thing is you do not want it to clip. The amp should have more than enough power for the sub, and it should get plenty loud enough before it gets close to clipping.

For the crossover setting, just play around with it to see where it blends in with the front speaker system well. I'm guessing it should end up around 80hz.

[B_Master_Flash]

Ok so i think i got this.....please check

If i want my final output power to be 250w (P).....

And it is a 4 ohm system (R)

Using what I saw at the JL site for bridged systems we divide the R by 2, then double the value we get for V.

V=(PR)^(1/2)
V=(250x2)^(1/2)
V=(500)^(1/2)
V=22.36 Double that and we get 44.72

If i meter across the bridged channels with the input sensitivity at min and get a value too high, should i decrease the LPF range to make up the difference? and currently my RCA jacks are run into the RCA ports that say "Line In", from the unit that branches off the rear speakers. The "Speaker level input" is some square port with pins inside. Should i be running to that input?

Please Help. Pleeeease!

Speaker level inputs suck ballz, rca adapters always sound better in my experience. With the input sensitivity at min you should get a voltage slightly above zero, and that method for benching amps (which is what I assume you're trying to do) isn't very accurate for actual output.

If you're trying to use the gain to limit output so you don't blow your subs, use your multimeter to find the voltage of your RCA outputs when you have the volume at the max you plan on using it (80-85% usualy), then set your input sensitivity slightly below that voltage. NEVER use the LPF to try to limit output, that's not what it's intened for, and more importantly it wont work.

[cam2Xrunner]

http://www.resnet.trinity.edu/areynol1/gain.htm

Just remembered I had that link about setting gains. Might be worth a look.