Let me start with the back story.
I built my home theater back in 2001 and have done a few upgrades to subwoofers since then. I started with a single 10" Titanic kit from Parts Express and added a second identical sub about 6 months later. They were good, but could not get super low, only down to around 26hz. I then built a new sub that replaced one of those 10" kits with a 12" Dayton Audio woofer in a 4 cu ft ported box I made that was tuned to 19hz. I have always wanted to get that fast, effortless bass response you hear in really good sounding commercial theaters and knew I didn’t have that, but it sounded good regardless.
Now fast forward to a few months ago. I started getting the itch to build something else and I started looking around at my options and found lilmike with the MicroWrecker Tapped Horn design which is similar to designs done by Danley Loudspeakers. I remember reading the posts by SandmanX years ago when he was making his theater and how he tried multiple subwoofers but the Danley was the one that stood out producing the best bass. I decided this was the project for me. I got the plans from him and being the mechanical designer that I am, I modeled the whole thing up in Pro-Engineer so I could get my own cut-lists as well as sheet layouts and figure out all the bracing.
I ordered an Alpine SWS-15D2 woofer and went out and bought some plywood and other supplies and went to work. I had Home Depot cut the width of the panels with their panel saw since it’s so much better than me using my table saw at home. It took me a few weeks to get it all assembled as I have other hobbies and activities that also pull at my spare time. I was going to stain the outside with a red mahogany stain and do a flat lacquer finish but after my wife saw the size of the sub, she told me I had to try to “hide” it, and that I needed to instead wrap it in the same fabric we have on the walls. Luckily I still had extra fabric and had enough to get the job done.
After getting it finished, my dad came over and helped me get it upstairs and into the theater and I quickly hooked it up to see if it worked and the beast came to life. I started by sending it some tones that started at 10hz and went up one hz at a time in 10 second intervals (downloaded from http://realtraps.com/test-cd.htm
) and you could see the woofer moving, but could not hear it, then it started getting into the regime where it really starts putting out the SPL and it was amazing! Not even broken in and we were hitting over 100db. I have a jumper between the voice coil posts so that the amp sees a 4 ohm load and I am powering it with my Dayton Audio SA1000 subwoofer amp which puts out 950 watts at 4 ohms.
The only measuring equipment I have right now is a Radio Shack SPL meter which drops off substantially below 20hz, so I don't know how high the SPL really is below that, but I can feel it. Someday I will get a measuring mic and use software that will enable me to give real data, but today is not that day.
Here is a screen capture from Pro-E showing the bracing in light blue, the flare parts in gray and the main shell in brown:
And a front image:
Here is what it looks like inside:
Here are a few finished and installed pics of it:
Here is my as-measured in-room response (with my limited measuring ability) with the amp’s subsonic filter on and off:
I think the room shape is causing the big dip at 36/37hz but that’s as good as I can correct it with my current amp’s limited EQ settings.
Friday night my wife and I did some listening to a bunch of different music and found it is very good for music, not just movies. We cranked up Techmaster P.E.B., Boston Pop’s 1812 Overture, Erich Kunzel’s Spielberg tribute and finished by watching the Eagles “Hell Freezes Over” concert DVD. It has a very fast response that packs a punch and goes very low and seems effortless; which was the main thing I wanted.
I applaud Mike for a great design and his willingness to share it!
Total cost to build was right around $350 (I already had the amp)