How to build and design tapped horn/folded horn subwoofers

Basically everything the DIY community knows about tapped horns can be found in this thread:

http://www.diyaudio.com/forums/showt...threadid=97674

The idea still intrigues me but I never got around to pursuing it. I think I made it to page 80 or so of that thread before I got sidetracked and forgot all about it (at least I made it over half way through)...

I need to print that entire thread out and put it in a notebook for reference. I have made it a few pages through, but I still want to know more. I am just not patient enough to read all 120+ pages in one or even two sittings.

1 - There may be some blurring between the two, but a tapped horn has one side of the driver firing into the horn at the "throat tap" (S2 in hornresp), and the other side at the "mouth tap" (S3 or S4 in hornresp).

2 - hornresp - flick through the help file to the section on tapped horns. The tapped horn wizard is where you'll do much of your tweaking. Maybe try someone else's input data as a starting point while you're learning.

3 - Tapped horns have gotten some very good subjective reviews, both commercial boxes from DSL and diy builds.

4 - Yes. For tapped horns it's easiest/most optimal to use a driver with Fs higher than your intended low cutoff of the horn. In my (very limited) experience drivers with higher BL will still produce a flat enough response with horn cutoffs higher than Fs. Depending on your application, you may have trouble finding a driver with correct Fs and enough Xmax.

The problem I have with the collaborative tapped horn thread is that its done mostly by people that already know about horn subs. I would, probably like dl86, to see a good beginners thread. Maybe a search for horn speakers in general would help to get a starting knowledge?

I completely agree. I kept reading even though I didn't really know the terminology, it started to make sense after a while although I don't think I'd remember now if I tried to read it again...

William Cowan's got some information on tapped horns at his site as well, follow the "Tapped Horn" link on the left:
http://www.cowanaudio.com/

I would just like to see more builds and less collaboration!

Agreed. Aside from knowledge and planning the actual build should be as easy as a standard braced box. More angles, but planned carefully the assembly shouldn't be that hard. I think the size involved with these builds along with the required knowledge shys people away from tapped horns.

I've been modeling drivers for months in Hornresponse and I've got a list of drivers that I think look suitable for a TH build at least from my limited understanding. I plan on posting them up at some point. I'd love to see some more people try TH's or regular bass horn builds and document them. I just haven't had the time to try one yet. Aside from the design challenge, actually laying out the path length, angles, folds and designing the enclosure in a compact and well thought out manner could be challenging.

I posted on the DIY forum about building a TH design using 4 B&K 12" woofers that I have sitting around. I wanted to make a stage in front of my HT screen and it would be cool for it to be a Tapped Horn.

I built a 20hz tapped horn with a B&C 15PS100 driver about a year ago. It was my first design/build along with two front loaded horns.

IMHO tapped horns are fantastic performers and when I get a bigger space I'll be building more. The main trouble with them (as someone else noted) is they are very large and heavy, it really takes two people to build them.

My build is on page 95 of that huge thread over at DIYaudio and there's even 'napkin' diagram with dimensions.

You'll save yourself tons of time if you can just copy someone else build.

Erik also has some detailed plans here. Good luck with it!
http://www.volvotreter.de/th.htm

That sort of thing just don't go around here...where's the fun in that? Seriously though for me the problem is nobody has done a build that I'd want to copy yet.

After you build your 18" LMS TH, I will copy you and build a smaller version for my 15" LMS......and with that shall begin an unending string of LMS copycat tapped horns. But you, my son, must initiate this epic journey.


Seriously, I still am not excited about having to cross an LMS TH at 50Hz or so and lose all that mid bass goodness. How high up frequency-wise did the TH-50 go cleanly?

If you haven't seen this documentation it may make interesting reading. Lot's of good construction pictures of the prototype being built.

http://www.pispeakers.com/Hornsub.html

That's quite a big box to have and then get the results they show in those shootouts. Response plummets in the low 30's. Give me a TH with low teens output at high levels--that's what I want!

I've been following Myn's THT folded horn thread daily over at Bill Fitzmaurice's forum. He is close to finishing, so I'm excited to hear his impressions. It doesn't use an uber driver, but interesting none the less since Home Theater is his application and he's coming from an EBS subwoofer.

http://billfitzmaurice.net/phpBB3/vi...ab25c1a705fde7

Dr V

Cowanaudio.com has a 18 hz tapped horn, but I think he used a driver that's not available to the public. He also has no build plans for that one. Most of the builds I have seen for tapped horns are 20-30 hz. For that I could just get multiple cheap drivers in standard boxes and roll with that. Give me a mid teens or lower horn with 125 db and I will be happy.

Problem I see with some of them is because of the nature of the enclosure interacting with the driver, xmax may not be reached, but the thermal limits can be reached sooner. That can be hard to deal with if you don't know the limits. Good drivers with stout voice coils shouldn't have a problem though.

I have to walk before I can run...


Remember I only heard the TH50 for a very limited amount of time in an unfamiliar environment. All I can for sure say is that it will get very loud and sounds very clean and uncongested while doing it. Big dynamics. I need more personal time with 4 of them in a small apartment. I'm not sure how high up the useable response goes. I thought I detected a bit of something going on up top when the crossover was at 100hz, but who knows. It could've been anything really. The poor little bookshelf mains were basically an afterthought at the levels we were pushing the TH50.

The Hornresponse models always have quite a bit of hash up top, but then I've seen some actual measurements that look considerably better. I've never built one and only briefly listened to others, so I don't know any more than you do. The guys who have built one say that it is not nearly as bad as the simulations predict and the Danley graphs certainly look good. (Who's to say that the DSL team doesn't have some magical enclosure tricks on a sacred scroll though?)

I use the term, "secret sauce" to describe those magical tricks inside the box. Danley has much sauce, as do Seaton's Terraform XLs. Wizards of Condiments they are!

If you look at the second to last graph on the tapped horn page at cowanaudio.com it appears to measure the hash exactly as predicted. I wish he has some more info on his 18Hz model there as well.

I wanted to be able to fit two 80hz front loaded horns and a 20hz tapped horn on a 14ft wall without blocking a 96" screen, so designing something myself, so it would fit, was the only option.

I really wanted to go a bit lower with the TH, but it just wouldn't fit between the FLH's.

I was actually caught between doing the THT and a Tapped Horn, notably a TH-SPUD clone using the Danley leaked plans.

I'm anxious to hear how the Tuba HT (THT) sounds in contrast to my EBS/LLT.

Hi guys I posted quite a bit of info on horn construction on a thread in diyaudio

It's under tapped horn for car. I can't post a direct link yet.

You get good info, a bit of me not reading the instructions and some constructive criticizism. As well as a review of the design.

While not a strict tapped horn there is a lot of design choices explained and there are real measured results.

Mark

Such designs were all the rage in the Pro audio world years ago, until Mobile PA production companies couldn't find grunts who were willing to move them!....along with 100+lbs amplifiers and the like. We left them in leased venues where they could stay long term. Searching around the older clubs and other dives you can still find them, under stages or stripper poles.( I know of one such place if anyone's interested? Each folded line is nearly 30ft long.) As a built in, such as a stage as someone mentioned earlier, a TH makes good sense IF you have the space. If space is limited and it must be mobile, there's better options for the modern HT IMO.

One of the main reasons horns are so popular is because where you previously required 8 traditional aligned cabs (sealed/ported), you can get away with half as many (4) horns giving the same output with less.

I know Bill Fitzmaurice horns are extremely light (under 100lbs).

I'm building one now to replace my LLT/EBS.

I was modelling the Mal-X 21 and decided to do it for the new stuff like 21nlw9600 (slightly higher xmax stuff, $650).
The TH-112 is about 300L and if I could get about the same SPL line across the freqs with a reflex cab with the 21nlw9600 (290L, fb =32Hz).

However I need about 3.6kW for the reflex cab, and the TH-112 1kW.

Its mentioned that amp power is cheap, now I need to get something which is cheap (EP2500 tested is just about 1500W @ 8 bridged).
Cheapest is American Audio V6001 as recommended by Bossobass a while back, 1.2k and gives 3.65kW at 1kHz (derate for 20Hz ops)

The amp + 18sound driver (no wood, no labour) already costs more than the TH-112. Of course you could save much more and just accept very slight compromises in SPL with say a 21lw1400 (you got it for cheap via ebay right), V5001 etc....
There are other cabs for different apps, and if you can accept slightly less SQ other maufacturers' horns gives even more output for less money. Anyway my 1200 cu ft room complains way earlier than the limit of the bins, even if its reinforced concrete. I think in branndon's GTG, the TH-50 was "pulled back" as things were falling off from the shelves in the room, rather than them hitting the limit.

What I see is that both horns and big-driver reflex cab both properly HPed gives out around the same distortion at the limit from what I see. But if you DIY and underport, that would be really bad for distortion. You could use light PRs, more costs of course. (References - new york shootout where they had horns and double 18s, audioroundtable)