Joe X

So it says that you have Hertz ESK 130, that's a 5" components, those usually start to kick in at 80-100Hz I'd say your gap is upper in frequency also, after all you said you tuned high and it didn't fix it looks more a gap in the 50-90 Hz region and not much below. I don't think going bandpass will help you with your problem, do you know for real the exact specs of the box you are using now??

Midbass drivers.

Fi SSD12 are 1000W RMS and are $204 each.. besides power handling they have superior sound quality.

If you listen to a lot of rap and also heavy you should tune low like 30-33 and the add some hefty midbass drivers, that will get you exactly what you are looking for.

You have 2 different issues that you should not confuse: 1) what enclosure is better for a particular sub. 2) what type of enclosure is better for a particular cabin For question 1 you calculate the following as a general rule: EBP = Fs/Qes <50 sealed. >100 Ported. between 50 and 100 you could use in either. For question 2 sealed will usually give you better transient response and lower group delay plus this: Since sealed has a roll-off of 12dB/octave and cabin gain raises at 12db/Octave starting at 50-90Hz you can get to cancel each other giving you a perfectly flat low frequency response. So properly used sealed is best for SQ. If your cabin is huge you can't get that and then ported is the better way to get bass.

Sub/amp combos: http://www.sonicelectronix.com/viewcat.php?category_id=103&from=857&sort_order=price_asc

The port displacement would be significantly higher, that's the prob.

10 sq inches of port per cube... wow but 32-35 is good for daily like fmedina said and box will also vary with power you plan to run I know it's 12-16 but I went by the Alpine manual multiply Vb x 4 and Port area X4, I mean I am hoping alpine knows what they are doing.. right??? Also they suggest to tune to 30Hz look it up... ok so where did you get 90sq inches of port from? im confused here Download SWR-1542D.pdf from somewhere look ay optimum ported enclosure and find that the recommended vent area per sub is 22.5 multiply that x 4 and you get 90 sqin, of course you have to calculate the lenght by formula.

10 sq inches of port per cube... wow but 32-35 is good for daily like fmedina said and box will also vary with power you plan to run I know it's 12-16 but I went by the Alpine manual multiply Vb x 4 and Port area X4, I mean I am hoping alpine knows what they are doing.. right??? Also they suggest to tune to 30Hz look it up...

9cuft@30Hz port area should be 90 sqin, it will be a huge box!

So loose it physically by unscrewing and then tap it while on, if it still does that check the fuse if you installed it, if not then it's something inside it.

As loud as possible without sounding like junk of course, I dont care if I have to change boxes, amps.. whatever.

I have 2 SA-12 in a dual chamber box 1.75cuft@34Hz (per chamber) on a MB Quart DSC 1500.1D amplifier, I want to get much louder what should I change to get the most of these subs, thanks in advance.

Are Audioque that bad? and also could you suggest something you liked in the price range?

The PVC pipe can stay inside with one cap to each end no need for it to come out, obviously the reduced Vb will increase tuning frequency, you can just keep taking up more Vb until you get the 30Hz. If you have the full dims of the port (cross-sectional area and centerline lenght) I could better estimate or you can do it if you know the equation.

No bracing? You could at least thicken the subs mounting surface.

A glued closed PVC pipe would reduce the effective internal volume and is reversible, changing the tuning is going to be harder, that's one of the upsides of airports.

But since the turn is smoother the losses on the turn will be lower so tuning has to change a bit. Anyhow with properly calculated port area and H/W < 9 you should not need any port smoothing.

You may want to take a look at this: http://www.ecoustics.com/electronics/forum/car-audio/697680.html

It makes music BIG enough to feel it.

This is a 5Khz 12dB per octave rollof high pass filter: http://www.parts-express.com/pe/showdetl.cfm?Partnumber=266-472

Expect greater efficiency easy on your electrical system and will not run hot, of course better output, regarding SQ not everyone likes it that much, if you care or even can listen a JL will still be better.

Its a high pass filter and the simplest implementation is a non polarized capacitor in series, will provide a 6dB per octave roll-off.

You do it with this free software: WinISD A little learning curve but it lets you calculate, sealed, ported and bandpass: 4th order and 6th order. Enclosures are built for your specific sub. Be warned build and align properly 4th order enclosures is hard, you have to do it perfectly.

You are not going to get any true bass from 6x9s, you get midbass at most, no matter how many you put, those speakers will not perform well on boxes, are designed to work in infinite baffle settings like your rear deck, will loose low end. 3 way will pickup earlier midrange frequencies which the big oval driver can't reproduce accurately. There are very good and inexpensive subs to choose from that will get you real bass (30-40Hz). Take a look: MB-Quart-FWA-304D