Need help - Car Audio Noobie at a loss on Sub/Amp setup (little to no bass)

[Russ Sedam]

I'm a hard rocker who wanted some punch when listening to tunes in my car. Nothing earth shattering, but enough to definitely feel the bass while in in my car with it cranked, without making the car next to me feel it too. With limited funds, past good experiences with Polk Audio home speakers, & some recommendations, I went with a Polk Audio PA 1100.5 (5 channel amp) and 2 Polk Audio MM1040DVC subwoofers mounted in separate ATrend BBox e10sv (single vented) enclosures. I wanted to have separate boxes so I could easily remove 1 or both subs for trunk space on occasion. The head unit is a JVC KW-XR810.

The amp on it's sub channel is supposed to do 600w RMS @ 1 ohm or 280w RMS @ 4 ohms. The subs are rated at 350w RMS & a peak of 700w. Originally, I had the subs set up with a 1 ohm load, which is when they blew. At Polk Audio's recommendation, I changed them to 4 ohm load. But in both configurations it seemed to me I wasn't getting good bass output.

My problem is I know nothing about setting up the system. My cousins BF claimed he did, but when he set it all up, there's almost no bass. I've been playing around with the settings on the amp and can get it sounding great by ear, but I've already blown 2 subs & had to replace them. So I watched Steve Meade's videos on clipping & setting up your amp with an oscilloscope & a sound setup disc with a 1kHz -0dB track.

Using the oscope, the head unit doesn't clip until 2 notches before the max volume of 50. And I've never had to turn it turn up past 30. Mostly between 15-25 if I'm really cranking it loud. When I set the gain and xover on amp to just under it's clipping levels, I get almost no bass from the 2 subs. In fact I got more bass from the 2 factory 6x9s that came with the car before I replaced them with polk audio speakers. I know the subs are phased correctly as I've doublechecked many times.

Can anyone here provide some insight please?

Edited April 21, 2012 by Russ Sedam

[michigancapri92]

What ohm are the coils on the sub, it sounds like they may have been wired really high ohm load so the guy turned amp gain up far to be loud but clipping bad and that's why they blew

[MrSkippyJ]

do the subs seem like they are getting good power? I know excursion isn't the end all of output, but are they at least moving? Phase is definitely a possibility but you said you have double checked. Check again maybe?

[ant the ninja]

Anyway you can check the ohm load?

[Guest]

you should have the subs wired like this

it doesnt have to be exactly like this, but all the +'s have to wired together, and all the -'s have to be wired together.

[Russ Sedam]

Sorry...the subs were originally wired at 1 ohm load. That's when they blew (due to my inexperience I'm sure). Polk Audio support suggested I change them to 4 ohm load so they wouldn't run so hot. Either was I'm not happy with he bass output of the subs unless I turn them up to what appeared to be clipping levels on an oscope. The subs move, but just barely, unless I put some Black Eyed Peas through them. I know rock music doesn't have near as much bass, but I expect more from 2-10 inch subs than I would get from factory 6x9's. Lol.

I've double checked the phasing again and it appears correct.

[DTS909]

What kind of car? polk does not recommend a vented enclosure.

[Russ Sedam]

Car is a 2008 Chevy Malibu. I was told I'd get more bass with the vented enclosures.

[MrSkippyJ]

Car is a 2008 Chevy Malibu. I was told I'd get more bass with the vented enclosures.

vented enclosures in general will have more output, but the speakers have to be able to work in a vented enclosure also.

and just looked up specs on those subs from Polk's website and it says the work in ported enclosures.

Edited April 21, 2012 by MrSkippyJ

[CleanSierra]

Not enough pre-out voltage from the deck. Turn your SUB level setting to max and then see what happens. I assume the deck has dedicated subwoofer RCAs.