Sub help and opinions please

[JasonK94Z]

Awhile back, I built the typical sealed fiberglass and mdf sub enclosure we all see on here to go underneath my rear passenger seat.

Powerbass L1004D 10" sub. Dual voice coil, running at 2 ohms. http://www.powerbassusa.com/sites/powerbassusa.com/files/L_Woofer 2013_Manual_2.pdf

Factory basic head unit, so I used an AudioControl LC2i line out converter. Using the bass output on it.

Amp is a Alpine MRX-M55 - 550 watts rms at 2 ohms


Got it all finished up, carpeted, etc. For one 10" sub, I guess it hits ok, but just not quite as hard as I anticipated from hearing other single 10's. Doesn't have that sharp thump.
So now I'm still left wondering, where's the beef? It makes good noise, just not what I have heard before in other vehicles.

Powerbass says optimal volume is 0.75 cu ft. Acceptable volume from 0.50 - 1.25 cu ft.
Dummy never measured the volume of my box. Worth my time doing it? What about the volume of the driver? Is it, the box minus the volume of the driver?

Is it the crap factory head unit holding me back?

Anything else I might be missing here? Perhaps insulation in the box?

Thanks

 

[Etroze86]

Definitely measure your airspace then subtract the driver displacement from that. If you get to big output suffers and can actually end up sounding a little sloppy when you apply to much power. The other thing to look at is where is your low pass xover set to on the amp. If it's to low like 50hz or less you won't get that good thwack, I would suggest start at 80hz and see how that sounds.

 

[Graygoose]

While its jamming, what's voltage AT the amp? If your not getting good voltage, your not getting 550 watts.

 

[JasonK94Z]

I will check into these suggestions and follow up after the weekend.

 

[DoubleTap]

Where did you tap factory speaker wire for signal for the LC2i? That could be your problem

 

[JasonK94Z]

Where did you tap factory speaker wire for signal for the LC2i? That could be your problem

I tapped into the front door speakers. Did the rears the first time around, and there was not much bass. I believe I even posted about it way back then.

 

[adurm]

You should be able to use a VOM on the RCA out from the LC2i and get AC volts (I think AC is used to test audio signal). Center pin is positive on the RCA. Don't let the VOM probe short across the RCA. You should see 2-5 volts I would assume. If not, adjust the LC2i and amp gain. You should be able to test the signal coming into the LC2i in a similar fashion. Did you tap left and right side or just one side? Make sure you didn't cross a pos and neg in the process. You can use the VOM to find out of course. Positive probe to what you think is the positive wire and neg to the other. Should show a positive reading, if negative then the wires are backwards.

Might be obvious to some, but I had issues with a LC6 because I had a neg and pos crossed coming in. Still made sound but not ideal. Took me many hours crammed in the rear seat of a genesis coupe to figure it out.

Afterthought: Maybe you can bypass the LC2i by running a headphone to RCA out from your phone and go straight to the amp. If it still sounds weak, then its localized to the sub/amp/box.