Lab12 - Tapped Horn -

[Don Snyder]

I left out "a. thru j. down the left side. Here's the fix.

[tb46]

Hi joqi59,

After reading through the Visaton Forum threads I tried simulating the enclosures in question, and Hornresp will give responses similar to the responses shown in the anechoic chamber graphs. As noted before, it looks like the tapped horn used as a comparison standard is sub-optimum.

I'll attach a TH_v._BR comparison with a different tapped horn model. I believe this puts the tapped horn in a more appropriate light, even if the TIW 300 is not the ideal TH driver. To me the TH clearly outperforms the BR in a subwoofer application.

Regards,

P.S.: I hope that layertone will have more information on his LAB12 build.

[Samuel Jayaraj]

Last night while listening to the Fostex 168Sigma's, I felt the need for a sub to cover the most bottom end of the spectrum. I pulled out my 2 unused Lab12 drivers and began contemplating on a TH vs ELF sub. I have a intuitive notion that the TH would sound more 'natural' requiring little or no EQing, thus matching the tonal characteristics of the Fostex.

However, looking at Don's TH fold for the Lab12, a footprint of 30"x13" would have low SAF. Hence, I was wondering if I could ask here for help to increase the height and reduce the depth of the TH. Someone might have already done it and I may not know. Can someone please point out to such a fold, if it exists?

Thanks,

[AndrewT]

Hi,
use a single fold TH rather than a three fold TH.
Double the height and half the footprint area.

[layertone]

What a busy weekend! didn't get a chance to revisit this until now & wow, lots of replies, thank you all

Originally posted by Sabbelbacke
Wow, love the pictures and the build quality, very nice!! Although this is build very rugged, you might consider some bracings at large areas, Since I´m in Pro-Sound, I use similar plywood as you do and I´ve always had to add some bracings and it always improved the sound (and made rumble from the enclosure walls less).

This is my first tapped horn build & also first build using the 3/4" Appleply (15 Ply's!!) Next one will have some braces for sure

Originally posted by tb46
Hi layertone,

Nice work! Please, keep us informed as to the placement of damping materials, and other progress.

Also, would you mind sharing name and number of the driver and CNC panel (elegant) mounting hardware?

Regards,

Details of this plan was posted by Don
http://www.diyaudio.com/forums/showt...12#post1586512

No damping materials used yet.

Hardware, i used "Self-Tapping, Threaded inserts" I like this better than t-nuts, much more stable & doesn't pop out like T-nuts.

http://www.mcmaster.com/#threaded-inserts/=1twnvs

Originally posted by steve71
Really nice work and great pics! I like that the driver is visible. My tapped horn is very similar in layout to yours and I get slick of putting on the hearing protection and sticking on my head in the mouth with a flashlight to monitor driver excursion.

I added a ton of bracing to mine, here's a pic if you're looking for some inspiration.

http://www.diyaudio.com/forums/attac...amp=1223240677

BTW how to you intend to finish it - i.e. paint, stain etc.

That extra Cat5 cable, i plan on mounting a set of RGB LEDs inside to light it up.

If suitable, i will take it to a truck store & have them spray truck bed liner on it.

Originally posted by Don Snyder
It's great when a plan comes together ...

MaVo did the simulation, Chris8sirhC decided to build the first one, and I did the fold
for Chris. Now, Layertone has built one of the nicest Tapped Horns of this series.

Great job & pics,
Don

Thanks for your help Don!

Originally posted by ashok
Great construction !
How does it perform compared to regular boxed sub's with the same driver ( sealed box ? ) ?
Horn's are great for high efficiency but how does this implementation compare ?
I'm asking because the chance of me coming across a similar setup is 'very' remote .
Cheers.

Not sure yet; maybe in the future i will build a regular ported box for this driver. So far it is SCARY awesome!! never experienced anything like it

Originally posted by Chris8sirhC
Those pictures look very familiar...

I did some corner braces (piece of wood 2''x2''x12'' on each of the inside fold corners. I also filled in that gap with expanding spray foam after it was completed. That space would be perfect though, for putting in a resonator or two, once you had figured out the correct length/tuning/etc.

I am thinking of having mine in a corner firing into the room through an opening in the door, and I would need to put on a small mouth extension to the horn. I am wondering if this would lower the tuning much.

Will certianly think about braces in the next build, thank you Chris

Still fiddling around with it so not sure about the extension.

[454Casull]

Originally posted by jogi59

In a 300 liters box is enough space for big enough ports

No
the tapped horn runs out of Xmax first

Visaton in germany measured a tapped horn and a vented box of the same size in their anechoic room. The surprising result was: the vented box went louder

Will the tapped horn gain more from boundary loading? I imagine that there isn't any in a truly anechoic chamber.

[layertone]

Originally posted by tb46
Hi joqi59,

I'll attach a TH_v._BR comparison with a different tapped horn model. I believe this puts the tapped horn in a more appropriate light, even if the TIW 300 is not the ideal TH driver. To me the TH clearly outperforms the BR in a subwoofer application.

Regards,

P.S.: I hope that layertone will have more information on his LAB12 build.

There was alot of rambling about tapped horns, I wanted to give it a try so a prototype test "teaser" i tried was the Tang Band 6", very surprisingly impressive for a 6"

The build, any specifics you would like to know?

the entire 2 sheet cutout was CNC routed...

By the way, any recommendations for amps? I'm currently using an under-powered Bash 300

**** correction for the link about the threaded inserts:

http://www.mcmaster.com/#92105a100/=1tx8c0

[tb46]

Hi layertone,

Thanks for the threaded insert information, have you done any comparison to the hurricane nuts (Parts Express)?

When you where building the prototype 6" (W6-1139SI?) did you have a chance to do some comparison between TH and other enclosure types, measurements or listening?

The Bash 500 is now on sale for $185.-- @ Parts Express, but excursion does become a problem for anything above 100W/6-Ohm into the LAB12 according to Hornresp. Probably not a big problem with music though.

Regards,

[littlemike]

Depends on your needs, but for $270 this is pretty hard to beat for home theater/audio use:

EP 2500 @ B&H

If you believe the ratings, it comes in at about 11.2 cents a watt, delivered. I've got one, it really does weigh in at nearly 40 pounds (same heft as my old QSC). While it is not a high-end brand name pro amp, it is still some pretty serious hardware.

If you're going to be in the same room, you'll probably want a quieter fan, which is easy to do, inexpensive, and well documented on the net.

Couple it with a DSP1124P, measure and dial in your response with RoomEQ Wizard, and you're set to go.

[littlemike]

The BASH 500 plate amp is not flat to 20 Hz as delivered.

It can be modified to be flat though, PE even provides some basic instructions. The modifications are not too hard (I've done two amps so far), but require some disassembly, desoldering, and soldering, as well as plenty of patience. The modification requires you to change two resistors on the preamp board to change the frequency and Q of the low-pass filter and remove the factory bass boost.