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Hi there,

So I'm relatively new to car audio but by no means am I green.

Just installed 2 DC level 4 m2 15's, on a DC 3.5k at 1 ohm. Custom ported box @31hz.

I'm having a problem with the sound quality coming from my subs. I can only describe it as an empty/hollow sound, that is most noticable on short notes. It almost sounds like my high pass filter is too high, and/or gain is too high. Instead of that nice clean deep quick hit it's more of a pop (not like a blown coil popping though). On longer bass notes it seems to change frequency slightly throughout the note, like it can't quite hold onto it. I've tried every combination of settings I can, on the amp and the HU and I've quadruple checked all my connections.

I am beginning to suspect it may be my head-unit. When I set the LPF on HU to 55/85/or 120hz and turn the LPF up on my amp up to ~250hz, you can hear vocals through the subs (I dont turn it up loud obviously). Seems to me like my HU LPF is not working on my sub channel, does anyone disagree? The HU is putting out 2.1volts on a 45hz test tone with sub level on 8/8, and 1/5volts on music with sub level on 8/8. So it's sending as strong of a singal as it should, I just suspect it's a dirty ass signal jumping all over the place.

Thoughts? Appreciate it.

08 Chevy Cobalt LS Coupe, Black

DC Soundlabs 3.5K
2x DC Level 4m2 15's @ 1 ohm
31hz designed by chevysub4x4spl

1x XS Power D3400

Stock Alt (mechman soon)

60ft 1/0 Copper Welding Cable

Alt, Batt, and Amp Power & All Grounds are 1/0 Copper

50 sq ft B-Quiet Ultimate & Cans of Spray Foam

JVC KD-A625

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Hmmm...

Box could be leaky?

Radio crossovers are nothing near perfect, that's why you fine tune on the amp.

Are you at the right impedance at the amp?

Did you hook the positive speaker wire up to the negative speaker terminals on the amp? Switching the polarity could, notice could, be the culprit. It changes the way the subs move. (stating from experience)

Just my ideas.

Car: 2011 Ford Taurus SEL / Alt: DC Power 270XP (Will be here 7/17!!!)

Deck: Pioneer AVIC-Z140BH / Amps: (1) DC 5.0k, (1) RF T400-2

Speaks: RF T2652-S 6.5" and RF T1692 6x9"

Subs: (2) DC XLm2 15's / Batts: (2) XS XP3000's

Wiring: Kolossus Fleks Kable 1/0 (2 runs)

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What HU ya runnin?

JVC KD-A625 it's pushing 2 years old now.

08 Chevy Cobalt LS Coupe, Black

DC Soundlabs 3.5K
2x DC Level 4m2 15's @ 1 ohm
31hz designed by chevysub4x4spl

1x XS Power D3400

Stock Alt (mechman soon)

60ft 1/0 Copper Welding Cable

Alt, Batt, and Amp Power & All Grounds are 1/0 Copper

50 sq ft B-Quiet Ultimate & Cans of Spray Foam

JVC KD-A625

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Share on other sites

Hmmm...

Box could be leaky?

Radio crossovers are nothing near perfect, that's why you fine tune on the amp.

Are you at the right impedance at the amp?

Did you hook the positive speaker wire up to the negative speaker terminals on the amp? Switching the polarity could, notice could, be the culprit. It changes the way the subs move. (stating from experience)

Just my ideas.

Box is sealed up cant feel any leaks around subs or terminals or any seams/corners. The noise I speak of is there at all volumes too even when there's really no pressure in the box. I read 1.0 ohms at the amp (1.3 but my leads are done for and show 0.3). Sub wiring should be good to go but that's one thing I need to double check, big time pain to pull subs out though so i'm trying to check everything else first as lazy as that may sound. If I did do that wrong, would changing the phase on the amp to 180 correct the problem(temporarily of course)? That was one of the things I experimented with and it didn't seem to help, it also didn't seem to make much difference (maybe that means something?).

Thanks man

08 Chevy Cobalt LS Coupe, Black

DC Soundlabs 3.5K
2x DC Level 4m2 15's @ 1 ohm
31hz designed by chevysub4x4spl

1x XS Power D3400

Stock Alt (mechman soon)

60ft 1/0 Copper Welding Cable

Alt, Batt, and Amp Power & All Grounds are 1/0 Copper

50 sq ft B-Quiet Ultimate & Cans of Spray Foam

JVC KD-A625

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I always set the LPF on the amp to around 70hz and the hpf on the h/u to either 63 or 80 depending on what i'm listening to.

That's about what i used to set it at with my JL w3's. Since I put these new subs and new amp in, anything over 35hz on the amp LPF starts to sound worse.

08 Chevy Cobalt LS Coupe, Black

DC Soundlabs 3.5K
2x DC Level 4m2 15's @ 1 ohm
31hz designed by chevysub4x4spl

1x XS Power D3400

Stock Alt (mechman soon)

60ft 1/0 Copper Welding Cable

Alt, Batt, and Amp Power & All Grounds are 1/0 Copper

50 sq ft B-Quiet Ultimate & Cans of Spray Foam

JVC KD-A625

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Yeah the phase is what it would change but if you already tried that, it's probably not that then.

Car: 2011 Ford Taurus SEL / Alt: DC Power 270XP (Will be here 7/17!!!)

Deck: Pioneer AVIC-Z140BH / Amps: (1) DC 5.0k, (1) RF T400-2

Speaks: RF T2652-S 6.5" and RF T1692 6x9"

Subs: (2) DC XLm2 15's / Batts: (2) XS XP3000's

Wiring: Kolossus Fleks Kable 1/0 (2 runs)

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Why the pass doesn't seem to be working correct is bugging me.

Have you ran a sweep/tones to see where your cutting off?

Edit- (anythin at or above 35 is worse??????..)....your not confusing the SSF with the low pass are you??

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