[z-lite]

about 3 cubic feet for the box, ill work on it right now

[supratreo]

thank you very much for all your help. do you use a program or just experience?

[joeybutts]

Good ol Z to the rescue!

The man.

The myth.

The Salsa.

Z will get you something right. no worries. you'll be destroying foundations in no time.

Most guys use some sort of program to optimize performance for the application.

[supratreo]

hey, i haven't gotten a reply from z, could someone let me know how i can go about designing this box? this way i can post my specs and hopefully z can chime in and give me his opinion

[z-lite]

Sorry supra, I've been really busy the past couple of days, haven't had a chance to enjoy sitting at my desk and working on the computer at leisure. I will make time when it's available to be made.

[supratreo]

no problem man, i figured you just got busy so i thought id do the leg work and get your aproval

[z-lite]

For some reason I can not reply to your PM supra but here is my response:
I did start working on it but the problem I'm having is that the port is super long due to the volume in the box and low tuning. With having so many turns in the port "path", that can cause port noise. Would you mind if I tuned it a bit higher in the 22-25 hertz range?

[supratreo]

honestly, i'm no expert so what ever you say if fine with me. but what about using a round (tube) port?

[z-lite]

Sorry for the delay:

http://www.icixsound.com/vb/nationpicture.php?pid=30900
http://www.icixsound.com/vb/nationpicture.php?pid=30899

Port area is 1.75" x 12"
Left/right side walls (2 pieces): 13.5" x 38.25"
Back wall (1 piece): 12" x 38.25"
Top/bottom (2 pieces): 13.5" x 13.5"
Front wall (1 piece): 12" x 35.75"
Port wall (short piece): 11" x 12"
Port wall (long piece): 12" x 27.25"

Assembly should be easy, it's a 2.5 cubic foot box tuned to 22 or 23 hertz I believe. As you can see from the 2nd picture, the long port wall "sits" on the short port wall.

[supratreo]

z, you are the man. i can't thank you enough for helping me out, especially during the holidays. i really appreciate it.
one last question, i promise
i'm going to use a LT500 amp, is installing it in the box factored in or should i do something else with it?

looks like i have my work cut out for me.
thanks again and happy new year.

[supratreo]

ok i lied, haha. if i use 3/4" mdf, what size roundover bit would i use to finish the corners?

[cptomes]

With single layers of 3/4" MDF and butt joints I wouldn't put more than about a 3/8" radius on it. I try to put glue blocks on the inside of corners I put a bigger radius on. Mitered and splined or biscuit jointed I'd be willing to chance bigger radius, up to the same radius as the thickness of the panels.

[cptomes]

Originally Posted by SpdSk8rs_Xa

You really won't want that high of a tuning for in an HT application. Keep in mind, HT subwoofer are often asked to reach down below 20 Hz, hence the reason the ported enclosures are generally tuned somewhere in the 20 Hz region or lower. 28 Hz is great for music in the car, not so great when watching War of the Worlds and it is asked to reproduce 15 Hz.

not so great == destroyed driver (without a high pass filter cutting off the signal below tuning)

The reason is that the mass of air in the port is resonating out of phase, and instead of keeping driver movement to a minimum (at tuning) it actually pushes and pulls in the same direction as the driver. So you get over excursion, exceeding the mechanical limits of the driver with very little power required.

[alexlindeman]

The LT.500 takes up so little airspace inside of the enclosure, you do not need to worry about it changing the design or sound in any way.

[supratreo]

for the reply. i also just realized that it will be mounted on the back wall (in the port) is that a problem for air flow?

[z-lite]

Yes, big problem. Can you keep the amp sitting somewhere else or do you want it in the sub box?

[supratreo]

that would be great but i can build a box for it.
thanks.

[cptomes]

I don't understand the problem. The box you proposed is big enough to put the port on the front with the driver or basically any of the faces keeping in mind the driver itself might interfere with it inside the box..

I would put driver and port on the front, amp on the back.

[z-lite]

If he were to put the amp in the back, that would get in the way of port airflow. There's about 8" between the end of the port and the top of the box which I don't think would allow enough space anyway for the amp.

[supratreo]

one more question, i normally use 1 1/2" drywall screws and wood glue for my boxes (3/4" MDF), should i be using something else?
Thanks