Quick Sub Box Design Help

[Mark the Red]

Hello All,

Just hooked up a great deal on this sub

12" HF Dayton Reference Subwoofer
http://www.parts-express.com/pe/showdetl.cfm?Partnumber=295-444

and this amp:

O-Audio 500w Plate Amp
http://www.oaudio.com/500W_SUBAMP.html

I spoke to PE tech support and they recommended a 4.5 cu.ft ported sub tuned to 23 Hz. The gentleman I bought it from recommended a 3 cu.ft. sealed box because the amp is apparently not designed for ported (?). And bass box pro recommended a HUGE ported box (repeat: HUGE). Also, modelling these three options in Bass Box Pro didnt really reveal much, aside from the obvious boost going ported does versus sealed. I do a lot of car stereo, but this will be my first home theater sub design. The PE gentlemen advised me against going too large a box as I will get sound delay cancellations from the port / sub.

Its going to be used 99% for Home Theater needs in a large 12ft+ ceiling x 500 sq.ft. room with hardwood floors. I have tons of real estate for this sub box, but would prefer a Q=0.707 design if possible. This sub will be placed in the corner of the home theater.

Long story short, I was planning on building the box next weekend so I thought I'd run it by you gentlemen.

I have no problem going sealed as I believe I have the power, but I read a few threads on this forum regarding the "tin-man" effect of going sealed with the Reference HF series subs.

Basically, all I'm looking for is an optimum design with a box size and port tune frequency. I am quite handy and will figure out all the port size calcs, etc.


Your help is greatly appreciated.

[jcpahman77]

If I understand things correctly the only reason you would have cancellation issues from a ported box is if the port is physically too far away from the speaker, but there are plenty here that are more qualified to answer that than I am. I am also fairly novice when it comes to building proper boxes for drivers but a quick look at those specs tells me a 2.5 cu. ft. box seems about right.

[Chris Roemer]

I spoke to PE tech support and they recommended a 4.5 cu.ft ported sub tuned to 23 Hz. The gentleman I bought it from recommended a 3 cu.ft. sealed box because the amp is apparently not designed for ported (?). And bass box pro recommended a HUGE ported box (repeat: HUGE). Also, modelling these three options in Bass Box Pro didnt really reveal much, aside from the obvious boost going ported does versus sealed. I do a lot of car stereo, but this will be my first home theater sub design. The PE gentlemen advised me against going too large a box as I will get sound delay cancellations from the port / sub.



That OA500w amp will be able to push 325w into an 8 ohm sub (YOUR sub).

Due to the nice suite of onboard equilization circuits, I would build a sealed box, with an internal volume of about 3.7 cu.ft. This has a Q of 0.74, but when stuffed (with polyfill or fiberglass) will yield an effective Q of 0.71.

Chris

[Mark the Red]

Thanks for the help.

[mikep]

Although the default hi-pass filters and amount of boost of the O-Audio amp is more suited to sealed designs, they can be changed by soldering in 2 different resistors like the Bash amps that P.E. sells.

The following boost resistor charts were provided by O-Audio.

https://spreadsheets.google.com/a/htshack.com/spreadsheet/pub?key=0Av4niF5ewWLLdE1hb1hSakF5Z3A3MmdCdHlzbkFna kE&output=html

[Mark the Red]

Finally got around to building this. Thanks for your help. Pictures are here (http://techtalk.parts-express.com/showthread.php?p=1768223#post1768223).

[Mayhem13]

Nice Job Mark!