Tapped Horns

While reading the forums, I got aware of someting called "tapped horns". It is an old enclosure principle which was rediscovered lately and now better understood and interpreted by Tom Danly. Here is his very interesting whitepaper white paper on his companys web site: Danley Sound Labs

The Eminence Horn

After reading this thread I was wondering if I could use one of two 15" I had left over from the Klipschorn. After some back and forth, an obsolete Eminence type EPS15-500 (Xmax 6,4mm) looked most promising. Even though the Xmax is limited I gave the following simulation a try (Note: as a direct replacement you can also use the current Eminence Kappalite 3015LF (Xmax 9,6mm), Eminence DEFINIMAX 4015LF (Xmax 9,0mm) or the MTX Audio T7515-04 (Xmax 16,5mm). Many others will work as well - just give them a try with hornresp).

The predicted response:

The parameters of the simulation:

The excursion simulation:

Regarding the room gain I like the idea of EQing the response down and gain some headroom.

The Eminence I'm using will reach Xmax with only a little above 15V @ 20Hz (115dB should be fine anyways).

This gives you an overview on the folding:

And this is what it looks like during building:

Except the inner bracing, which were 16mm, the thing is made from 22mm MDF. All connections are glued and screwed. It took me a weekend to build it.

Here is the baffle cutout for the 15" speaker.

This is before sanding:

This is my old Eminence EPS15-500 in place. As I pointed out, the Kappalite 15LF will fit also (very similar response, more max SPL due to higher xmax - 9,6mm insted of 6.2mm).

When I brought it into my room first, I thought: Oh my god, this thing is big.

Here it is in my room. After errecting it in the corner it still looks large but not as bad as before, when it was laying in the middle of the rool. Paint will be applied in spring and of course, If I still like it then. The mouth points toward the left hand side.

In the evening I did some testing. I heared some music and watched a movie. It sounds very effortless and goes deep down. Great for HT and music.

The plans can be found in the download section.

The Tangband 30Hz Tapped Horn

I listened a lot to the first tapped horn I built for the 15" Eminence I had laying around. What I must say is that I like the bass of the unit a lot. Is sounds very accurate and precise. The sound is what I would decribe as effortless and easy. The best bass I had in the system. That's for shure.

After listening some evenings with my friends, one of them wanted to know if it would be possible to build something like that but smaller (better WAF, what the one for the 15" doesn't have). I serarched a lot for possible drivers, and to make a long storry short, I ended up with a 6.5" Tangband. Since they are so cheap and to have some more headroom and flexibility in regards to placement I built two units for this guy (and for my pleasure):

Note: Access panel to cover the speaker is not installed on this picture (it will be mounted on the aluminum rails).

For testing I placed them simply in between my mains, right next to them. Especially compare them (65l net) to the 15" TH (430l net) in the right hand corner:

I was very curious on what they are capable of. And after a weekend of listening I have to say that the result is way beyond my expectations. Sure, the big one goes deeper and louder, but they just sound great. Very well controlled and smooth, down to the lowest registers. I found myself several times not believing that only the two small TH's were running (but the big one and the Klipsch were disconnected). They are able to produce very remarkable volumes, much more than usually required for listening music as well as HT. They are capable to keep up with my mains in every way.

Here are the input parameters:

Here is the predicted response:

This is the theoretical SPL in quarter space at 20V where Xmax (11.5mm !) will be reached.

As I said, I built these two for a friend of mine. Since I fell in love with the Tangbands, I already ordered another 4 of the speakers to built some more TH's like that.

Finally an incredible bang for the buck (at least in my eyes and for my purposes). Very easy to build (I glued them togeter in my living room) and a lot of fun. For an amp I used the unused rear center amplifier from my HT amp. The xover is a 30€ Reckhorn unit. Total investment for the speakers, the MDF (16mm) and the xover approx. 150 Euro.

The plans as well as a design util can be found in the download section.

The Tangband 38Hz Tapped Horn

I simply could not withstand to build another pair of TH's with the remaining 4 drivers I'v got. This time the goal was to build some TH's which will extend a little further up match to the conical midbass horns. Therefore I choose to make the horn shorter and crossing at 100Hz will hopefully be possible.

Here are the input parameters:

Here is the predicted response:

The response starts to rise at 100Hz with approx. 18-20dB/oct. The irregular peaks at 180Hz and 250Hz are predicted not to be stronger than the range below 100Hz. Others who built TH's also reported that the predicted peaks were not as bad in real life. My guess was to xover at approx. 100Hz and so to be able to get an usable response to maybe 100Hz or even a little beyond. Note that the design includes the use of 4,7mh coils to even out the response. I will use these:

They are wound from 1,32mm dia. copper wire and have a Rdc of 0,26 ohm.

Some pics of the TH's I took while building them:

I had to make the mouth opening a little larger than initially desired because I wanted to be able to install the driver without a removable panel as I did on the 30Hz TH further up. I changed the simulation accordingly in Hornresp but the difference in response was neglectable.

This time I also used a little thicker MDF (19mm for all panels) and additional bracing. Actually I was surprised how much the 30Hz TH's flex when turning up really bad. I simply did not believe that this could happen with such small driver.

This is how I folded to get the 15cm longer S12 (over S34) into the box.

Note the braces I installed to avoid vibration and flexing of the panels. The top of the box has also a brace connection it to the inner divider.

Done. Sanded and wired with terminals and speaker installed.

A close-up of the driver which fitted perfectly.

The plans can be found in the download section.

In the meantime the 4,7mH coils are installed and I must say that I like the small ones a lot. Actually, now my Klipschorn moved out of my living room. Integration is much easier with the TH's compared to the Klipsch corner horn.

Later I also built a double folded version of the 38Hz Tangband TH because it better fits into my room:

Here you can see it compare to the initial single folded version. An advantage of it is the stiffer enclosure.

Parameter wise it is completely identical but it is double folded. The plan for this TH is also in the download section.