Guidance needed matching sub woofer drivers to enclosure volume

[Ray Collins]

I am re-cycling a pair of Bozak B302A Century enclosures for use as sub woofers in my HT ( room size is 13' x 14' ) and need help selecting drivers to suit the enclosure volume. The Bozaks were trimmed to 24" x 24" x 14" to fit at the ends of our sofa so they will also serve as end tables. They are made of .75" dense particle board or flake board veneered in a very nice walnut ( Is this material OK for a sub woofer enclosure? ). Replacing the front baffle with one 1.5" thick and adding four internal braces .75" thick brings the internal volume to 3.27 cubic feet. Using a plate amp reduces the volume to 3 cubic feet.

My tentative list of drivers is as follows:
Dayton RS315 with a Parts Express plate amp. This modeled to 3 cubic feet with a Qtc of 0.6 in a sealed enclosure.
Rythmik DS15 with plate amp which is a 15" driver and probably is overkill.
TC Sounds but I can not make one of their drivers fit my volume.

My wife and I do not use high volume levels when watching movies and I much prefer accuracy over other traits. Budget is not restricted but I do not want to build a Ferrari to drive to the grocery store.

Any and all input will be greatly appreciated.

Ray

[augerpro]

A TC2000 should model well in that. I little more money though...

[Ray Collins]

The 12" TC 2000 requires a 1.8 cubic foot sealed enclosure and the 15" requires a 3.5 cubic foot sealed enclosure....problem is that my enclosure size does not meet either of these size requirements. Can you explane how the drivers are compatable? Perhaps you deviated from the factory Qts?

Money is not a problem.

Ray

[ThomasW]

The 12" TC 2000 requires a 1.8 cubic foot sealed enclosure and the 15" requires a 3.5 cubic foot sealed enclosure....problem is that my enclosure size does not meet either of these size requirements.

Requirements? No, those are simply recommended box sizes to obtain a given set of performance parameters.

The RS315 is a nice woofer. The low Xmax is a bit problematic unless multiple drivers are being used.

Bigger drivers with a higher Xmax (and Vas) can be used in smallish boxes. The Qtc can be lowered electronically through the use of an LT-Linkwitz Transform circuit. This is how virtually all the better small box self-powered retail subs function.

If money isn't a big factor and you want a all-in-one, 'plug-n-play' solution get a pair of the Rythmik 15" and matching amps.

If you want more flexibility of choice and more creative control of the design, there are certainly other options. However most involved stand-alone amps and additional electronics.

[Ray Collins]

Thomas,
Thanks for the response. The Daytons are eliminated. I understand the LT circuit's function and the use of EQ to raise the SPL as the frequency declines--I think. I am not as familiar with the function of the servo except that it is a closed loop feedback system that governs the cone movement; does this mean it increases xmax to raise SPL as it declines?

I have neither the measurement nor analytical equipment to set up the subs once they are installed if this is a factor in your guidance. I am not adverse to purchasing what is needed nor am I reluctant to learn to use it but for this application is it worth the effort(considering room size, lack of placement flexibility,etc.)?!

Further, I intend to build five new speakers for the rest of this HT system(5.1). I want them to all be the same drivers etc. as Jon and you are currently pursuing in your new project.

Thanks,

Ray

[ThomasW]

In private correspondence Mr Ding (Rythmik) has indicated no one except those with IEEE's are qualified to discuss his designs. As a result we honor his wishes by not discussing the technical aspects of his products.

If nothing else you might consider investing in a SPL meter and some form tone generator (PC's are great for this) to measure the in-room response.

Even though placement is fixed you can use EQ to some degree. Unfortunately the number of EQ bands included in most plate type amps is only sufficient to create frustration....

http://home.comcast.net/~thomasw-2/SubwooferSetupandEQpage.html

[Ray Collins]

Thanks Thomas; I read the first six chapters and will finish the rest tomorrow night. Very helpful.

Ray

[---k---]

A TC2000 or SoundSplinter RL-P15 (basically the same driver) will give you the most output, and likely biggest bang for the buck. I had a pair of RL-P in sealed 100L enclosures for a while (they are now housed in the refrigerator sized ported now). Pair them with a Behringer EP2500 amp, and you'll be able to shake the house.

I would get them in the house and play with the location. Depending on how much you yearn for that low <20hz sound effect in movies, you'll want to add a Behringer DEQ (I got on of those too). It really isn't that hard to install and setup - especially if you are just trying to add low end LT to your sub. Using it to get a better room response isn't that hard either. The DEQ is easier to setup than the cheaper and oft mentioned BFD, which makes it a winner in my book. But, the BFD may sufice for you dependinng on your room and desires for low low hz.

Anyway, we can help.