Due to a large amount of requests I have spent some time designing a simple version of my Infinity Kappa VQ Build. These plans would likely be easily completed by someone with wood working experience in less than one day. A novice would probably want to take more time, but shouldn't have much trouble with this design.
The graphs:
Transfer function:
SPL versus frequency at 400 watts:
Cone excursion at 400 watts:
Port air speed at 400 watts:
The CAD design:
The cabinet is 22.5" wide x 22.5" deep x 25" tall with a port that measures 12.5" wide x 55" long x 3" tall.
With the top taken off:
Front baffle and top taken off:
Side taken off as well:
One cross brace removed as well:
Cut list (Use 3/4" cabinet grade plywood):
Front baffle: 21" x 24" Rear baffle: 22.5" x 24" Sides: 21.75" x 24" Top/Bottom: 22.5" x 22.5" Cross brace (large): 16.5" x 21" Cross brace (small): 6.25" x 21" Port bottom: 2x 18" x 3"
17.25" x 14" Port back: 2x 24" x 3"
18" x 14" Port top: 2x 13.75" x 3"
13" x 14"
You will want to get some OC705 or 8lb Rock wool to place inside the cabinet. Use a 4" piece wrapped in cloth (to eliminate chances of pieces being blown out the port) and glue it (using 3m Spray 77) to the large brace.
Recommended amplifier EP2500.
Thats everything. Optional things you can do to increase sound quality:
1) Round over/cove the port corners with a router. This will decrease air turbulence and minimize chances of port noise/compression at high SPL.
2) Integrate the unit with a DCX2496. This will also allow for equalization of your subwoofer for maximum perceived sound quality.
3) Build 2 and integrate as a stereo pair with the DCX.
**Please note I make no guarantees about actual performance as there are a variety of factors that effect such a unit.***
Feel free to ask any questions either here or via PM.
__________________
Andrew
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Andrew makes no mention of possible in room performance levels. But, with his slightly different, and for more complex version(in terms of bracing, fascia and round overs in the slot port), he achieved maximum SPL of 120dB at 20hz, corner loaded, and measured at a little over 2 meters away in distance at the listening position. This was the in-room SPL for 1 unit powered by a bridged Behringer EP2500 amplifier.
I don't know if this result can be achieved on average with this setup - but it is his maximum result that I found impressive.
Theoretically, How would a single, or stereo pair of this compare to say, the Axiom EP500 or 600 or PB13 ultra?
It is not fair to compare a pair. The potential output of one of these is so great, that it would be very similar to a PB13 Ultra, except that the PB13 would not have as much output in the lowest range, because the port on Andrew's design offers less compression due to the large cross section area, and the PB13 would potentially offer greater output by some degree, in the higher octaves, because of it's larger cone surface radiation area. But to realize the output potential of the Kappa Perfect cabinet design above, you would need to use a bridged EP2500 to deliver sufficient peak power. However, one does not need this level of capability in actual use. It's overkill. However, stereo units are always going to provide better ability to integrate with the main speakers, even if you don't need the output ability that is possible.
I know this is an impossible question to answer but sound quality wise, Is this really going to be THAT good?
The reason I ask is because I have been shopping around for a sub for a while now and everything that i really like is out of my budget by the time I get it shipped here, I am in the process of hopefully getting a used EP2500 for a great price and am now thinking of going the DIY route. I looked at lowes yesterday and 4x8 sheets of 3/4 MDF are only 40 bucks I figure I could build the cabinets for just around 100 bucks, With this design I would probably even laminate a second layer of MDF to all outside panels for even greater weight and rigidity.
I wish there was more info on actually building this exact design and doing comparisons with commercial products as I would really want to know for sure that if I am going to drop close to a grand to build a stereo pair of these that they are going to devastate anything else I could have gotten commercially, especially the subs I have asked about. Particularly because my parents theater room has the EP600 which i have used in my system for a month or so, and have been quite pleased with its performance for my uses.
Simple 12" Infinity Kappa VQ MidQ Plans
Big thanks to avaserfi for this.
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