Here is my first foray into building tapped horns. It uses the MCM 55-2421 8" driver and the 115W Foster plate amp from Jack Hidley. This entire build cost less than $100 including wood and hardware.
It has external dimensions of about 29.75"x35.125"x9.5". I actually built this sub about 2 months ago and have been enjoying its clean sound in my living room since then. It is tuned to 28Hz and will provide 110db down to this frequency.
Here are my new arrivals. For $25 each I had to get a few extras.
I hung these in my basement and drove all 6 of them with a single 115w amp to break them in. These were broken in at 30Hz for 48 hours.
These parameters were slightly different than my originals but have been adjusted slightly due to folding which changed them a bit.
The schematic. It was kept at 3.5 cubic feet before folding.
The SPL response at 2.83v input. Nearly 95db down to 28Hz.
Max SPL--Over 110db down to 28Hz
Driver Displacement--According to HR it is slightly over Xmax but the amp rolls off at about 28Hz as well which should help to protect the driver.
Here is the drawing in AutoCAD which makes it very easy to fold the horn. In this drawing the amp will fit at an angle in the upper left of the pic. The driver will sit directly next to it.
The enclosure is nearly completed at this point. It took a mere 3 hours to assemble once all of the pieces had been cut. The 1/2" plywood that I used is some inexpensive stuff from Lowes that was slightly warped that they marked down to $7 a sheet just to get them out of the way for them. I used the PL premium and a brad nailer which made assembly very easy. Highly recommended!!!
I really didn't want to stick an amp in my entertainment center so I built the amp into the box. I know that BFM strongly frowns on this but the amp is plugged into the same outlet as my receiver as well so no ground loop issues here. I also wanted to make the enclosure as slim as possible so I made it 8.5" wide internally. This required me to mill down the amp to fit. Good bye warranty!!
Here is a pic showing the driver and amp installed in the box. Note that airflow from the enclosure will also help to cool the amp, not that it gets very warm anyways. It's a very tidy slim package.
This is the completely assembled enclosure. To this day I have not finished the enclosure. A buddy of mine wanted to buy this one but hasn't picked it up yet. He wants to finish it himself.
Here is the home so far of this tapped horn. For scale that is a 50" Samsung Plasma next to it and my latest project, my 64" tall TLAH's. Sitting back in the corner like they are and aimed towards the corner they really don't use up any extra floorspace. If I do end up keeping this sub I may paint it to match the walls to better help it blend in.
With a total outlay of less than $100 I have been extremely pleased with this overall package. Although they don't hit the lowest notes they sound amazing with movies and just incredible with music. Clean and loud explain it well. Keep in mind that this replaces my Onkyo 5100 HTIB sub with its 10" "sub" and 290 peak watt amp. For hardcore movie watching I still rely on my 4 sealed IXL18's in my basement.