Which Subwoofers get really low?

[Dwn2rth]

I'll explain this as clearly as possible. Never in my 15+ years of owning car stereos have I run into this problem. I typically buy setups with a decent head unit, amp, replaced interior speakers and subs. I currently have a Kenwood 4volt deck, Kenwood 9152 sub amp which seems to be enough for my taste, and 2 12" Diamond Audio D3's in a sealed enclosure to spec 1.5 cuft per side. My question is, why don't they hit the low lows on songs like Money Maker by Ludacris? I've tried various configuratons on the amp cross over and deck, both and one at a time. No matter what it's still not making audible the lower notes. All the typical rap bass songs are fine like Lean wit it, Rock wit it. I have some R&B tracks as well and it just falls apart on the super low notes. Iv'e been told I need woofers with low Fs and a high Qts. So it would seem the Diamonds need a ported box because the total is over 50 on the calculation with Fs / Qes. So for a sealed box that would rule out Rockford Fosgte P312D2 = 51.92 /DIAMOND AUDIO D312 = 52.77 / ALPINE TYPE-R 1222D = 63.63 /JL Audio 12W3v2-D2 = 52.37. Or would a high Xmaxx help. Yes no one can tell me how to fix this. I'm thinking new subs. You can see by what I've listed for the price range if you have any ideas....

Thanks

[mikee55]

You need to go to diy Audio Forums>Top>Car Audio

[ocool_15]

you should specify which model you have. There are 4 12" D3 currently listed. Recomended Q is a bit high, .707 butterworth is more common. F3 is often in the mid 40's for a 12" sealed car application.

[Dwn2rth]

I have the D312D2 model

[owdi]

Check the specs on your signal processors and amplifiers. Many car audio components include rumble filters that block the really low stuff. My Audiocontrol EQL and 2XS have 33hz 3rd order highpass filters.

EDIT: and you want an overall LOW in box qts. Something like .6 will have a big low end in a car.

Dan

[ocool_15]

They have a higher qts and fs then I would normally look at.
A lower fs(all else being equal) will improve the low end extension. Qts itself I would not use to indicate how low a speaker will play. A higher Qts is better suited it is to a sealed enclosure and low Qts will indicate a vented box with ~.35 being the middle ground.

If you use an application like winISD you will get a better idea.

[owdi]

The attached image demonstrates the difference between a subwoofer with .6 and .8 qts. I modeld my sub (sealed Blueprint 1001) in my car (scooby wrx sedan). Note the low qts sub has a broad peak around 32hz, while the higher qts sub has a sharper peak around 50hz.

Dan

[Dwn2rth]

Thanks for the reply! Yes I called Diamond about it earlier today and they said those subs need ported boxes to hit the low lows. Do you know of any other brand/models good for sealed enclosures such as the JBL P1222?

[Dwn2rth]

Originally posted by owdi
Check the specs on your signal processors and amplifiers. Many car audio components include rumble filters that block the really low stuff. My Audiocontrol EQL and 2XS have 33hz 3rd order highpass filters.

EDIT: and you want an overall LOW in box qts. Something like .6 will have a big low end in a car.

Dan

Thanks, I did turn off the subsonic filter which helps but again the sound of the super low freq are not as loud as the bass notes around 40hz. Typical rap bass. Lil Jon etc.

[Dwn2rth]

Originally posted by owdi
The attached image demonstrates the difference between a subwoofer with .6 and .8 qts. I modeld my sub (sealed Blueprint 1001) in my car (scooby wrx sedan). Note the low qts sub has a broad peak around 32hz, while the higher qts sub has a sharper peak around 50hz.

Dan

Very interesting! Now i need to find a nice 300-400rms low Qts sub! Any takers?