Inexpensive entry to the world of Tapped Horn subs...

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Here is my entry to the world of tapped horn subs. I wanted this to be as low of cost as possible, with reasonably good performance.

Design Goals:
1. Single sheet of plywood.
2. Extension to the low 30's if possible.

After what must of been 8 billion simulations. Then 4 billion fold attempts. I looked at at least 50 or 60 drivers in the $50 and under category.

Lots of the car audio, DVC 8's were promising but typically required such a long horn that more than a single sheet of plywood wouldn't work.

Lots of pro-sound drivers had great output, but not enough extension for my purposes.

I looked at the ubiquitous MCM high excursion 8, which is roughly half the cost of my eventual choice. The issues I had were: concerns regarding T/S accuracy and unit to unit variation, foam surround, and a far less advanced motor structure.

After looking at a whole bunch of options I settled on the Dayton DC205-4. $52 was a bit more than I wanted, but with a rubber surround, copper cap on the pole piece, vented pole and a high linear excursion it looked like a pretty good choice.

I started with a folding the same external dimensions as the TH-MINI from DSL, but it ended up a little bit larger in order to get the extension I wanted.

Because I love a good palindrome I'm tempted to call it the TH-MINIM-HT. Cause, who doesn't love a good palindrome?
 

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As fast as I can....

ok, holidays over.... :)

Sorry guys, still trying to recover from the holidays! My wife and I adopted two little girls this year. Yikes. Very...different life! I used to go to high end restaurants and try different molecular gastronomy recipes. Now it's Hello Kitty and casseroles.

I'll try and get at least an impedance sweep done before the end of this weekend. In room response is a possibility too...anything more than that might have to take a bit.

I will say this..I'm as interested as anyone. My current sub is a dual Peerless XLS 12", 12" XLS PR in about 80L. I might prefer the sound of the Dayton. It is waaaaay closer subjectively than I ever thought it would be. When I was running all of the simulations in Hornresponse, I thought....nah...these numbers are all too good to be true. Now...I'm believing. I've got a Dayton 12" Titanic MK III design that I might build next. 6dB more output, by calc...than my dual Peerless XLS 12 sub.

My wife is so going to kill me.

Scott
 
ok, holidays over.... :)

Okay I was able to do a quick impedance sweep. Which took two hours, because Praxis was being weird. My thoughts:

1. It's even closer than I expected...even up to the higher order modes.
2. Looks like some bracing around the mouth might be in order...even for this sub.
3. Looks like the copper pole cap is doing it's job on inductance, though the higher than predicted impedance in the 300Hz to 2kHz is a bit weird.

Scott
 

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