Official Value Buster Subwoofer System design info thread.
As the title implies this design allows you to get lots of bass from an inexpensive driver an easy to build enclosure with flexible tuning and allow for multiples to be powered from a single iNuke amp.
The driver for this design is the Dayton PA460-8, an odd choice for a subwoofer design you might say. True, but with the right balance of enclosure, power and proper EQ it does amazingly well. Similar to the Magnum-12 woofer in the Flex-12 the PA460 is very efficient in the mid bass leading to very little thermal compression and great dynamics in that range. While it is a bit limited in terms of coil overhang it does have a very soft suspension and decent mechanical clearances so there is no trouble pushing it a bit at lower frequencies. I have done thorough testing with the iNuke 3000 and the driver stays safe even when driven hard below tuning with the DSP settings limiting any bad noises from either the driver or the amp when being pushed hard into the limiter as was demonstrated at ENG-399's where a pair was run at reference with the sub trim about 16dB hot.
The enclosure is a fairly straightforward ported box, approximately 6.25 cubic feet net internal. Measures 23.5" wide, 31.5" tall x 20-20.5" deep (depending on double baffle or not). If going with a single baffle layer and surface mounting the enclosure can be cut from a single 4x8' 3/4" sheet of MDF or plywood. Add a 2x4' sheet of 1/2" if you want to flush mount the drivers and ports which is how I built mine.
Here is the cultist for the enclosure without the additional 1/2" front baffle to flush mount the driver and ports. To flush mount the driver all you need to do is cut the outer diameter out of the 1/2" baffle and that will put it flush. Theoretically you could add the second baffle layer at any time without making a new box or adjusting the cuts on the inner baffle.
Note 30" x 2" piece should be cut into smaller pieces to fit between the side to side and top to bottom bracing, I just forgot the exact dimensions which making the cultist. It should be measured during assembly anyway to determine exact length of parts needed.
Here is a look at the bracing I used, feel free to add more or beef it up if you wish, but I found that to be adequate:
Here is a look at the damping I used in the cabinets. It's R-13 recycled denim/cotton insulation with a piece placed on top the port tubes below the driver that is held in by the brace and a couple pieces placed on the walls above and behind the driver leaving space above the ports for airflow.
The design uses two of the 4" precision ports at full length which makes things very easy. Using both at full length gives you a 20 Hz tuning, if one is plugged you get 15 Hz and if you remove the center extension tubes you get a 31 Hz tune. You can use masking or electrical tape to hold the ports together if you want to leave open the option of removing the port extension tube. The proximity of the internal port flare to the rear wall makes the effective port length longer then it would be otherwise which allows for the tuning to come in lower then what it looks like it should calculate out to.
The VBSS is meant to be used in conjunction with the iNuke 1000DSP or 3000DSP amps. A 1000 can power up to two of these in bridged mode while a 3000 can drive up to 8, 4 per channel. This allows you can get a lot of bass without spending big bucks or have a rack filled with multiple subwoofer amps.
Here is a look at the outdoor 2pi frequency response for the 15hz, 20hz and 31hz modes (with DSP):
Rough idea of the 2pi max output from a single enclosure powered by an iNuke 3000:
A zip file with the DSP settings for the iNuke amps is also attached.