Small Full Range Driver in TL for office

[adwilk]

Cutting six ¾" MDF panels where the outside and inside cut patterns are identical will be tough.

Cutting those 6 pieces of MDF to the exact same outside dimension will be tough enough, but it probably can be done with a saw of some kind, but I doubt if jig saws work well with ¾" MDF. I personally would go to a Home Depot, Lowes, or a decent lumber yard where there's a large panel saw plus someone who knows how to use it. Get them to cut six panels that are 12" × 21". Take the time to figure out how many 12×21 panels you can get from one 4×8 sheet of MDF. Get more than six. You'll probably have to sand or use a router with a bearing bit to make them exactly the same outer dimensions.

The irregular inside cut pattern looks like it will require making a router template. In addition to a router, you'll need ¾" template collar bushing, plus a ¼" (or ½"?) spiral upcut bit. The collar bushing should work better for this than a bearing bit. The patterns you now have should be useful for the first step to make a router template.

See the PDF I attached for directions on how to flushmount an irregular shaped tweeter faceplate. Or see this: https://www.reddit.com/r/diyaudio/comments/4ysmms/tutorial_ how_to_flushmount_irregular_shaped/

I say all this like I've done it before, but I haven't. I watched while someone else did it, so it looked deceptively easy . I don't know how much router experience you have, but it's going to take practice. Be prepared for that idea with extra MDF or Masonite boards to use.

That’s immensely helpful. If I make a deeper pattern/template I’ll be ready to go. I’ll cut the pieces out of larger than needed sizes so that I can size them down on my table saw. I feel pretty confident I can make them all pretty much the same. A little sanding should produce good results.

 

[adwilk]

I did not know you were going to use MDF.

Horns are different. Donald Chave of Lowther taught me as a kid, that the panels of horns must actually not be too rigid and have internal damping. Lowther horns are still built from good quality 3/8" plywood!

Does that mean this design should be avoided? The nature of the design- plywood or mdf should be exceptionally rigid.

 

[TLS Guy]

Does that mean this design should be avoided? The nature of the design- plywood or mdf should be exceptionally rigid.

Not at all. The design will still be structurally rigid if you make it out of 3/8" ply. It is just over time people who have built horns realize some materials are more suitable and produce a better sound than others. This is true of all horns, instruments, speakers the lot. It is just that the construction material used has to be somewhat 'live" and not "dead".

 

[adwilk]

Not at all. The design will still be structurally rigid if you make it out of 3/8" ply. It is just over time people who have built horns realize some materials are more suitable and produce a better sound than others. This is true of all horns, instruments, speakers the lot. It is just that the construction material used has to be somewhat 'live" and not "dead".

But wouldn't this change since I would be laminating 13 sheets of 3/8" per speaker? (4.875 wide for baffle) I see what you're saying if it were a traditional box with folded parts, but this isn't that.

 

[TLS Guy]

But wouldn't this change since I would be laminating 13 sheets of 3/8" per speaker? (4.875 wide for baffle) I see what you're saying if it were a traditional box with folded parts, but this isn't that.

I get that. I don't think it will matter if you use 3/4" ply. But I would use plywood for this enclosure rather than MDF.

 

[adwilk]

I get that. I don't think it will matter if you use 3/4" ply. But I would use plywood for this enclosure rather than MDF.

OK. Thats an easy enough change to make! Thanks for the insight.

 

[ski2xblack]

http://telavox.web.fc2.com/mm151s02.jpg
Those use thick pine planks (sorry for the link, can't seem to get the image to post). Could be worth considering, less messy than mdf. Here's a link to that site, it's pretty laugh worthy.

TOP_Exponential Back Loaded Horn Speakers

elimination of the standing wave at the folded place of the horn. Hasehiro back loaded horn that you've known up until now has changed completely in new back loaded horn speakers.

telavox.web.fc2.com

 

[adwilk]

http://telavox.web.fc2.com/mm151s02.jpg
Those use thick pine planks (sorry for the link, can't seem to get the image to post). Could be worth considering, less messy than mdf. Here's a link to that site, it's pretty laugh worthy.

TOP_Exponential Back Loaded Horn Speakers

elimination of the standing wave at the folded place of the horn. Hasehiro back loaded horn that you've known up until now has changed completely in new back loaded horn speakers.

telavox.web.fc2.com

Well if these are only suited for jazz, I’m out. Interesting. Thanks for those links.

 

[TLS Guy]

Well if these are only suited for jazz, I’m out. Interesting. Thanks for those links.

What absolute nonsense. Horns are not just suited for jazz. That is not true and ridiculous!

 

[adwilk]

What absolute nonsense. Horns are not just suited for jazz. That is not true and ridiculous!

Oh, I agree with you! That was very tongue in cheek. I’m pressing on.

I’m going to visit the math again to make sure I’ve got the numbers right. Surely DSP can make these things sound decent enough and still satisfy the aesthetic goal.

 

[TLS Guy]

Oh, I agree with you! That was very tongue in cheek. I’m pressing on.

I’m going to visit the math again to make sure I’ve got the numbers right. Surely DSP can make these things sound decent enough and still satisfy the aesthetic goal.

If the specs are right then it should sound very good. Cone break up does not start until 10 kHz. So if it has a bit too much very high top end you can pull it down 10 db at 15 KHz. However you might really like it just playing it straight. There is actually something really addicting about horn loaded speakers. There is a good reason Lowther are the oldest speaker company. Watch it, this speaker might make you splurge on a Lowther driver.

I have a feeling these little speakers may be a lot better than you think. The horn will really pull the bass up.

 

[adwilk]

If the specs are right then it should sound very good. Cone break up does not start until 10 kHz. So if it has a bit too much very high top end you can pull it down 10 db at 15 KHz. However you might really like it just playing it straight. There is actually something really addicting about horn loaded speakers. There is a good reason Lowther are the oldest speaker company. Watch it, this speaker might make you splurge on a Lowther driver.

I have a feeling these little speakers may be a lot better than you think. The horn will really pull the bass up.

I have a little experience with horns. You're definitely getting me excited about working through this project.

I built a pair of the Frugal Horn MK3 using the Mark Audio Alpair gold 4" a few years ago and they live in my den. They're probably my favorite speakers I've owned. They draw me in every time I turn them on.

Those 2" panels are probably a little high- but high frequencies should be mostly projected forward. I haven't put bass traps on that wall yet- I'm planning to swap tv for projector and that'll change everything. I haven't treated the ceiling yet, so the panels are helping with some overhead slap. It was honestly a guessing game without any kind of measurements for correction, but they seem to do the most good there currently. There are two more panels on the opposite wall and adjacent side wall.

 

[ski2xblack]

You (as well as previous input from tls) have me wanting to do a similar project for my tb w-8 1772 drivers, which are currently in mltl cabs. Keep up the good work.

 

[TLS Guy]

I have a little experience with horns. You're definitely getting me excited about working through this project.

I built a pair of the Frugal Horn MK3 using the Mark Audio Alpair gold 4" a few years ago and they live in my den. They're probably my favorite speakers I've owned. They draw me in every time I turn them on.

View attachment 34877

Those 2" panels are probably a little high- but high frequencies should be mostly projected forward. I haven't put bass traps on that wall yet- I'm planning to swap tv for projector and that'll change everything. I haven't treated the ceiling yet, so the panels are helping with some overhead slap. It was honestly a guessing game without any kind of measurements for correction, but they seem to do the most good there currently. There are two more panels on the opposite wall and adjacent side wall.

I have been looking for an excuse to use those Mark Audio drivers for a long time. They are the direct descendants of the Jordan Watts Module. I have a lot of those. I used JW modules for my ceiling Atmos speakers and they are superb. If I had not had the JWs I would have used Mark Audio speakers. I am absolutely convinced they are the best speakers you could use for ceiling Atmos speakers. I doubt the usual speaker selected, (yes, those horrific abortions with tweeters stuck in front of the cones), would come anywhere close to using those full rangers.

 

[adwilk]

I have been looking for an excuse to use those Mark Audio drivers for a long time. They are the direct descendants of the Jordan Watts Module. I have a lot of those. I used JW modules for my ceiling Atmos speakers and they are superb. If I had not had the JWs I would have used Mark Audio speakers. I am absolutely convinced they are the best speakers you could use for ceiling Atmos speakers. I doubt the usual speaker selected, (yes, those horrific abortions with tweeters stuck in front of the cones), would come anywhere close to using those full rangers.

What would the enclosure/mounting look like to put those drivers in the ceiling?

 

[killdozzer]

What would be the easiest way to explain the difference between the enclosure in the first pic and the TL?

I found this image and found it strange that it does not taper.

 

[TLS Guy]

What would be the easiest way to explain the difference between the enclosure in the first pic and the TL?

I found this image and found it strange that it does not taper.
View attachment 34898

That enclosure is an acoustic labyrinth, but incorrectly designed. I think the designer has gone for compact size. That speaker would have a nasty peaked one note bass.

 

[killdozzer]

That enclosure is an acoustic labyrinth, but incorrectly designed. I think the designer has gone for compact size. That speaker would have a nasty peaked one note bass.

Thank you. Even though I don't know much about this topic, something seemed wrong.

Do these designs demand a full range driver? Could you have solid results with point source, like coaxial drivers?

 

[TLS Guy]

Thank you. Even though I don't know much about this topic, something seemed wrong.

Do these designs demand a full range driver? Could you have solid results with point source, like coaxial drivers?

Yes, my center line TL uses two SEAS prestige coaxial drivers.

The lower speaker is fed from one channel of a Quad 909. The top driver, uses a modified for purpose Shure SR 106 crossover feeding the other channel of a Quad 909. This signal provides active continuously variable BSC. These drive units from SEAS are based on an older KEF design and built under license from KEF. They do have a response irregularity in the 9 KHz range and above. The tweeter of the top unit is fed a correction signal for this problem. Others have found it a problem to get a really pretty much perfect response from these units. I have managed through a number of iterations of the electronics to get a really good response from this center speaker. This proved to be the most difficult aspect of the whole design of this novel TL speaker system.

The above was in the old room on Benedict Lake.

This is the on axis FR in the new room. Note quasi anenchoic measurements below 250 Hz are somewhat influenced by the room. The electronics are the same, but BSC had to be increased in the new room.

New Room

This is an absolutely wonderful center speaker. That reproduces the human voice with very high intelligibility without shout or chestiness. It has excellent coverage to every seat. It is by far the most natural sounding center speaker I have ever heard. It is now a real keeper.

So the short answer is yes you can, and it works well!

 

[killdozzer]

@TLS Guy This is really fascinating. If I understood correctly the two drivers are not playing the same signal?

I'm going to come forward and just say what's on my mind; long time ago you mentioned a DIY competition that also has a category for less skilled builders who use some proprietary parts in building their projects. From that moment on I kept wondering how would a TL speaker sound using the UniQ from LS50:


But going for the full range sound in an enclosure like this one: