99Bluz28

iTrader: (35)

So is the port designed to have the tuning frequency easily changed..?
It looks like you could add an extension on fairly easy to lower the tune frequency.

Daniel Richards

iTrader: (1)

found the Steve Meade build http://www.stevemeadedesigns.com/boa...?hl=aqfirebird

nitrodude

The port is actually completely removable. Remove a few screws and it slides out.
Plans are to open the port up (get some more port area) and raise tunning a hair. Then make one port for a nice low running, and another for higher tunning to compete. Right now I just have the one port in there tuned to 34hz, And my car peaked @34hz on the termlab as well.
Like I said 149.0@34hz, Hopefully opening up the port and raising tunning I break a 150.

Yup, crazy build.
The build that actually inspired mine is the "AQfirebird"
He did 4 aq hdc3 12"s firing forward, port back, on 4 aq 2200's.
I was going to do the same general thing but subs up port back (Since sub forward port back usually causes a lot of cancellation)
I'm Pretty sure the only reason his didnt, was because with how big the port was, and it loading off the hatch and coming forward, it pretty much acted like a huge ported horn firing forward.

Daniel Richards

iTrader: (1)

you've got me thinking on a few ways I could possibly boost the volume of the box on the underside and then maybe close off the front port, remove it's pieces and "bump" up between the 2 subs to create a rear facing port (with the added bonus of improved airflow over the amp, LOL), I kept it simple before because I didn't feel the extra math and advanced cutting angles where worth the effort.

Avaric3

iTrader: (3)

aiming the ports backwards I could easily see making a large difference. I did some placement testing wit my sa12 in a sealed box and when I had it aimed forward or aimed up in the back seat, it felt like nothing compared to having the sub aimed sideways or directly up at the back of the hatch.

also, the flat area just behind the back seats didn't have to close to as good of a response as the back of the hatch area did as well.

nitrodude

Do it, Its worth it
My box was a little more complex because I needed to squeeze a bit of airspace out of the back area.

Thats because firing forward the sound waves dont get to fully form, when firing back youre loading off the back hatch.

nitrodude

Whoops, just actually clicked the link and looked, thats the build that inspired mine, The AQ firebird. Let me see if I can find the 18"s camaro.

Found it.

Ment to say Steve Mead without an E LOL

http://www.floridaspl.com/forums/showthread.php?t=23063

Daniel Richards

iTrader: (1)

I used a cardboard box from a package we got at work yesterday, basically my new port would be about half an inch shorter and 2.5 inches wider then the box but it would run all the back to the end of the MDF top of the box with the port pointing right at the amp.

Also attached is another picture I snapped of the setup while I was putting the t-tops in the back yesterday.

nitrodude

Hmm.
Is there Any way to make the box sit higher up? Then cover the front port, and cut a slot port out of the back and make most of it external like my box.

If not try that, worst case, It sounds worse cover it up and go back to firing forward lol

Daniel Richards

iTrader: (1)

the box height is pretty fixed, short of a total rebuild, and I did it that way because it was the look I wanted, here is a pic of the box during assembly so you can see why it couldn't be done like you described. the top actually hangs over empty space on the back half.

For what its worth in the paper work for these subs it calls for 1.5 cubic feet interior volume with a 3" round port that is 8" long (with all supposedly being a 31 hertz tuning frequency), so square inch of port I'm running is already larger then what the specs call for and I recalculated my interior box volume (including the current ports) and not counting displacement of the subs I'm at 3.38 cubic feet interior.

nitrodude

Im not sure what type of port area you're using with slot port, but you NEED more slot port area then when using an aeroport.

I would do around 13sqin slot port per cube if you can.

Daniel Richards

iTrader: (1)

As it sits the math is about 1.69 cubes per side (internal volume) with 15.5 square inch of port per side, I know it's small but any bigger a port area and it would make the port to LONG to fit in the box how it has to.

Keep in mind I'm more looking for SQ then SPL these days, I haven't competed in years.

nitrodude

Do you have a router?
Do a roundover on the inside and outside of the port-It'll help with the air flow

Daniel Richards

iTrader: (1)

I have access to my dad's router, I think more then anything I really need to be focusing on getting more power (both in terms of alternator output and amplifier output) if you where to believe the max output number of my amp it is still around the max power handling of just one of my subs, A friend of mine knows a guy looking to do an ENTIRE system from the ground up (HU, wires, amp, sub) and I'm hoping to sell my old setup to him and maybe I can sell him on this amp so I can get the next model up.

nitrodude

Dont look at max/peak ratings of amps or subs-they pretty much dont mean jack.
Look at the RMS wattage, thats the real number that matters.
What are you looking to step up to in terms of amp power?
Unless you're going up a bit-you really dont NEED an alt, I ran 3k rms for years on stock alt daily.

Daniel Richards

iTrader: (1)

I'm looking to jump up from the 1250 RMS to like 2k RMS and I've already done the big 3 with Knukonceptz 0 gauge and have a less then a year old Optima Redtop and a 6 month old Brand New (not reman) alternator (I had to get it when I did because the stock one crapped out on me while I was on my lunch break and I had to get the car running so I could get back to work) and even with all this I still get headlight dimming while doing 55 down the road if I turn the volume even one notch above normal listening volume (39 on a scale to 62 with 48 being what I would use to "show off")

nitrodude

Sent ya a PM

Your headlights will dim a little no matter what-If your voltage is a 14.5v, Unless your alt has enough amperage to supply your car+amp with enough juice, youre voltage is going to dip into battery voltage (Most batts rest at 12.5ish volts) And dipping from 14v to 12v will cause your lights to dim some. of course dropping to an even lower voltage will make them dim worse.

99Bluz28

iTrader: (35)

IMO, at least double you wattage or you're wasting your money and time.

Avaric3

iTrader: (3)

and even then, doubling wattage will only give you a 3db increase

nitrodude

No, Not necessarily.
I had the same subs/box, three batts, two runs of wire, stock alt, on a crunch Ground pounder 3000.
My score on the term lab was a 147.4@38hz.
I bought the nendo 5500, a 300amp alt, and got remetered (Nothing else changed just upped my amp power, and upped alt power), Got remetered and did a 149.0@34hz.
Gained 1.6db and lowered my peak from 38hz to 34hz

Wish I would of gained 3db, I'd be into the 50's! LOL.

Hopefully going today to get my port worked on to raise my tunning and play on the termlab to get my score up, I'll update with pics if I get it done.