Joe X

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

You would just discharge the battery after a while.

So what is wrong with the sa-12s?

pitbullninja, no audio hardware is for free..lol.. there was a thread next to yours asking about some cheap junk speakers which are rated 2500W plus free tweeters so they recommended them here in your thread for fun.

Yes, for free try them!

which 6.5"s and against what.

pitbullninja, it all comes down to how much you want to spend and how hard you want an installation to get, for $70 you can get well balanced full range sound and easy installation. There is no denying that you can improve over them, the best way to know is to go and hear a few 6x9s and 6.5" components to get some idea of their differences.

I have tried a few of them away from a car environment in big enclosures, many people use midbass drivers with comps help this.

My point is that 6.5" components lack midbass, the only components that really sound great are those with 7"-8" midbass drivers. 6x9s give great midbass, if you are not a SQ guy you not be bothered by their sound at all. Sanitarium you should try Focal 6x9s

6x9s have better midbass than any 6.5" components. And sound plenty well for the price. Now if you are a rich audiophile you can buy a nice $1000+ dynaudio 3 way component set for your doors, better than 6x9s for sure.

One decent option could be this: http://www.sonicelectronix.com/item_17734_JBL-GTO928-GTO-928.html

They have a long history of reliability issues, poor sound quality, malfunctioning peripherals and the xplod series has been stellar at that and you can dismiss specs, even if really had 120dB SNR, in a car environment that is good for nothing, it's too much to say that a particular model from them will be good or bad but there are so many alternatives that I wouldn't bother to take any chances.