I'm about to give up, help please!

[Johannes]

I am having trouble getting my sub to pound in my 1991 Nissan Kingcab. I have a Clarion head unit with Pioneer 2 way 6.5" speakers in the front. I recently purchase the Pioneer GM3000T 200w max 2 channel amp, which supposedly puts out 100W x 1 when bridged. I have an 10" MTX 6000 series sub that was sold to me but when I took it out of the box it has a remanufactured sticker so I will return it soon. The kid working there lied to me. Anyways I also have a Rockford Fosgate 10" P110S4 subwoofer. MTX recommends about 0.5 - 1.0 cubic ft. sealed for that sub and Rockford recommends 0.65 cubic ft. sealed enclosure. The enclosure the MTX came in is over 1.3 cubic ft, but that's measuring on the outside... so factoring in the 3/4" wood and the displacement of the sub it's probably around 1.0.

I have tried hooking up the MTX bridged and it won't pound, it will barely do anything. Same with the Rockford, it will barely do anything. My cheapo speakers up front are putting out more bass than the sub does. The only way to actually hear the sub pound is to adjust the balance on the head unit all the way to the rear and then turn the volume up to about 30, which normally way too high a volume level.

Does this sound right? I also tried a crappy Pyramid 1600W max 2 channel amp bridged and same thing. Since I have tried 2 amps and 2 subs I don't know what is going on. Is it because it's a sealed box?
I have a wiring kit I got from Wal-mart that's rated for 550 W max, 275 W continuous.

Any help you guys could offer would be great. I've always wanted a sub in my truck but I don't want to have to return this stuff and give up! Thanks.

[sr20de4evr]

what's the impedance of the subs and how is the gain on the amp set?

[Johannes]

4 ohm subs and I've tried the gain on all settings it doesn't help! I usually try it with the gain around 60% though.

[sr20de4evr]

hmmm

well this won't affect anything, but your box is a max of .88cf, minus sub displacement, so closer to .8cf. That's if it's a perfect cube, if it's rectangular it will be even smaller than that. That size is fine, I'm just letting you know so that if you need to know the box size for some future sub or whatever then you'll know.

as for the problem, is the amp set to lowpass? what is the cutoff frequency set at? which preouts on the headunit are you using (if it has more than 1 set)?

[Johannes]

The box is almost a square... 14" x 14" by 12". Did you just calculate by subtracting 3/4" off of each side?

I have tried low pass on and off. I don't know about the cutoff frequency. The headunit has two sets of RCA plugs - front and rear, I've tried both.

Is it a huge deal that my head unit doesn't have sub outputs? I could have gotten that when I got my head unit a few years back but I didn't.

[sr20de4evr]

well first I assumed it was a cube, but yes then I subtracted 1.5" off of each side (2 walls). If it's 14x14x12 then it's .95 minus sub displacement (looks like I did too much rounding when I found it before ), so around .9 after sub displacement.

does your headunit have a highpass feature for your front and rear speakers? It's not a big deal that you don't have sub preouts, as long as the preouts that you're using instead aren't highpassed.

[TheSilentChamber]

Do you have something cross wired?

[Johannes]

I was wondering how you got to .88 because I subtracted 1.5" off each side as well. Anyways I don't think it has a highpass feature. When you say preouts you mean RCA cables right? My head unit has 2 - one front and one rear.

I don't think I have anything cross wired. I have checked everything over a bunch of times and read the instructions for the sub, amp, wiring kit and head unit. For the wire from sub to amp, I am using 14 gauge home speaker wire, it has copper and silver color, I always use copper color as positive but it doesn't say on the package. Does it make a difference which wire you use as neg. and pos.?

[RickwithaTbird]

you can use either color, just dont get it mixed up. its common to use copper as positive. Yes those are your front and rear pre outs. I didnt see it mentioned in this thread so im gonna ask... have you checked your ground wires.. particularly the ground wire from your amp. The wire terminal on the amp labeled "GND-" should be connected to a bolt which is directly connected to the frame, and it should be a rather clean connection.

[sr20de4evr]

yeah, those rca plugs output the signal before it reaches the headunit's internal amp -> "pre-amp outputs" -> "preouts"

as for the wires, no it doesn't matter, not only does it not matter which of the 2 wires you use as postive, it doesn't even really matter whether you wire the sub's + to the amp's + or the sub's + to the amp's - ("backwards" so to speak). It would sound slightly different if you wired it up backwards, but nothing like what you're experiencing.

The only thing I can think of is that your headunit is highpassing the signal, and then the sub amp is lowpassing it, so in the end everything is filtered out and barely anything is reaching the sub.

Try taking a cd or mp3 player, just some kind of portable player, get one of those cables that converts the 1/8" headphone plug to a pair of rca plugs (you can find them at best buy or radio shack), and then plug those into the amp. Keep the volume low and play some song, if the sub starts working fine then it has to be some problem with the headunit's settings.

[RickwithaTbird]

Originally Posted by sr20de4evr

as for the wires, no it doesn't matter, not only does it not matter which of the 2 wires you use as postive, it doesn't even really matter whether you wire the sub's + to the amp's + or the sub's + to the amp's - ("backwards" so to speak). It would sound slightly different if you wired it up backwards, but nothing like what you're experiencing.

oops, I kinda made it seem like it mattered. sorry I didnt think to clarify that. But as a side note, for future reference, if you hook up multiple subs on separate channels, dont be careless because they should be wired the same way.

[sr20de4evr]

right, if you have multiple voice coils or multiple speakers you have to make sure you're consistent, but the actual polarity doesn't really matter, just as long as you keep it the same for everything.

[Johannes]

I had it grounded to a metal part below my stereo, where my heater comes out... the same piece of metal my head unit is grounded to. I also have tried it bolted through the driver seat bolt... but that bolt isn't too clean.

I have one of those headphone to RCA cables... I could try that with a discman.

I have tried hooking up the sub to a 8 ohm home system and it was okay... well I had to crank it but it was decently bassy, for a home system hookup.

[RickwithaTbird]

have u tried turning off your high pass filter and play it at a low volume (so as not to blow your other speakers) and see if the sub plays louder. Im thinkin the same thing SR20 is, which is that the HPF is killing any signal your sub might get.

[Johannes]

The amp has a low pass filter... just an on and off switch, I have tried both and they both seem to be the same. I'll try again though.

How would I go about adjusting the high pass filter on the Clarion head unit?