Here's My Usher/Altec Horn Loaded Open Baffles...

[tinitus]

Chops, nice speaker ... I prefer flat angular baffles, much like electrostatics, seem to visually blend better than odd shapes

And you have proven that there are other ways to OB

Good information that high effectiv drivers can take a good deal of EQ with out reaching their limit 😉

Also I think you have made a good choise with the "studio" woofer rather than the PA version ... the low Fs=26hz of the studio woofer may be an important key to your succes

 

[Brett]

Also, the more efficient the driver is, the less you have to worry about Xmax as it will take little power to get loud.

Volume displacement determines the SPL. The only difference with higher efficiency is you'll need less power to do it.

 

[chops]

That's an awe inspiring system Chops. You should ping Dennis Bohn at Rane, I know he would love to see what you are up to.

All of you want to be very careful with EnABL and horns.

Bud

Well thank you BudP. I'm glad you like it. It certainly turned out better that I imagined. BTW, why do you think Dennis Bohn would be interested in my setup? Just curious.

Also, a dumb question, but what exactly is EnABL?

Chops, nice speaker ... I prefer flat angular baffles, much like electrostatics, seem to visually blend better than odd shapes

And you have proven that there are other ways to OB

Good information that high effectiv drivers can take a good deal of EQ with out reaching their limit 😉

Also I think you have made a good choise with the "studio" woofer rather than the PA version ... the low Fs=26hz of the studio woofer may be an important key to your succes

Thanks Tinitus. I was also thinking of a shape similar to the Carver Amazing Loudspeaker or Apogee Stage, but decided I needed as much baffle as possible with the low Q Usher drivers.

How have I proven another way to OB, because of the integration of a horn? Come to think of it, I've never seen any other OB/horn setup before. Maybe mine's a first! 😀

I find it amazing that they take so well to so much EQ in free air. Even on those peaks I was talking about earlier where they reached 10-12 watts max, the drivers were hardly moving. Then again, 12 watts is apparently nothing to a driver that can handle 150 watts RMS.

Yeah, you may be right. Even if the 15HM's are a lower Q driver, their Fs is definately lower which I'm sure helps out.


And on a side note, I just have to say that I can not get over the quality of midrange that comes from these 15's! It's so natural, clean, powerful and transparent. All the detail in the recording is reproduced, at least from what I can tell. I think that's probably my most favorite thing about these speakers. Not to mention that it comes in such a large format. IOW, the sound seems to come from the entire height of the speaker, and whoever is singing at the time seems to be at the proper height for standing or sitting at a microphone. It's a bit difficult to explain, but I'm trying! 😉

 

[chops]

Volume displacement determines the SPL. The only difference with higher efficiency is you'll need less power to do it.

Exactly, less power means less movement from the driver, which means more volume before reaching Xmax.

 

[Brett]

Exactly, less power means less movement from the driver, which means more volume before reaching Xmax.

No.
If you have a 15" speaker excursing 1mm, it will be giving the same SPL whether the driver is 100dB or 80dB sensitive. The latter will simply be using 100x the power to do it.

 

[chops]

No.
If you have a 15" speaker excursing 1mm, it will be giving the same SPL whether the driver is 100dB or 80dB sensitive. The latter will simply be using 100x the power to do it.

That doesn't make any sense. How can that be?

I have had 4 different 15" driver in the front of my room. I have seen all 4 reproduce 50Hz at the same volume. Some use more power than the others, but they also travel more/less than the next at that same volume/frequency.

 

[Zen Mod]

......

Also, a dumb question, but what exactly is EnABL?





.........

tide fence for sound wall which propagate through speaker cone ...... bouncing from surround and basket rim back in cone ;

that is Bud's invention - to achieve propagation of that wall out of cone, in phase with primary emanating sound wall ;

simple ,isn't it ?

in any case - more effective than stitching surround to cone

 

[Brett]

That doesn't make any sense. How can that be?

SPL is about pressure and the quantity of air moved. Move the same volume of air at the same frequency and it will be the same SPL. How you move it doesn't really matter.

 

[CLS]

..... I've never seen any other OB/horn setup before. Maybe mine's a first! 😀

No, it's not.

http://ldsg.snippets.org/HORNS/images/systems/unityh.jpg

See here for more interesting stuff:
http://ldsg.snippets.org/HORNS/


However, your Usher/Altec OB is really a good work. Congratulations!

I've been thinking to do similar things, but that'll be in the future when I move into new apartment. So actually I'm fighting with all these teases. Oh, man, it's hard.

I got 4x Eminence 18inchers and Oris horns ....

 

[Brett]

I got 4x Eminence 18inchers and Oris horns ....

I'd like to hear about that one when it gets underway.

 

[BudP]

Chops,

In simplest terms, it removes the "hall of mirrors" from loudspeaker sound. In the case of the 15" drivers, it would cause all of the 50 dB down resonant energy created by an orchestra's string bass section to become as available as the pluck, or bowing, fundamentals. Plus all of the echoes, even further down, that describe the symphony hall's sonic character and size. Just a lot more dB down of coherent information. Pretty easy to do and not expensive.

Bud

 

[Pano]

Come to think of it, I've never seen any other OB/horn setup before. Maybe mine's a first!

Sure you've seen one before - mine! 😀

But we aren't even close to being first. The cinema guys like RCA, Western Electric and the Germans did it back in the early days of sound.

It's still cool, though...

Bear is always saying to try the horns vertical. 😱 Will have to give that a listen sometime.

 

[chops]

No, it's not.

http://ldsg.snippets.org/HORNS/images/systems/unityh.jpg

See here for more interesting stuff:
http://ldsg.snippets.org/HORNS/


However, your Usher/Altec OB is really a good work. Congratulations!

I've been thinking to do similar things, but that'll be in the future when I move into new apartment. So actually I'm fighting with all these teases. Oh, man, it's hard.

I got 4x Eminence 18inchers and Oris horns ....

You're such a kill-joy. LOL

I think mine might be a MTM first with a horn though. Maybe? 😀

Thank you!

And yes, I would be interested in seeing that build as well. You do realise that I still have enough room on my baffles for some 18 inchers as well...

 

[chops]

Chops,

In simplest terms, it removes the "hall of mirrors" from loudspeaker sound. In the case of the 15" drivers, it would cause all of the 50 dB down resonant energy created by an orchestra's string bass section to become as available as the pluck, or bowing, fundamentals. Plus all of the echoes, even further down, that describe the symphony hall's sonic character and size. Just a lot more dB down of coherent information. Pretty easy to do and not expensive.

Bud

So pretty much just deadening the baskets, horns and such and/or eliminating reflections?

Sure you've seen one before - mine! 😀

But we aren't even close to being first. The cinema guys like RCA, Western Electric and the Germans did it back in the early days of sound.

It's still cool, though...

Bear is always saying to try the horns vertical. 😱 Will have to give that a listen sometime.

Ah yes, of course I have! Sorry, it's been a long day. LOL

Yes, but did any of those cinema guys of old ever build MTM versions?

Hmm... It would be a bit of a pain to try and mount my 511's vertical in these baffles now. Why don't you try it and tell us how it sounds?! 😀

 

[BudP]

Chops,

So pretty much just deadening the baskets, horns and such and/or eliminating reflections?

Hmmm, not exactly deadening.

When listening to reproduced music, from an orchestra, a lot of inner detail becomes masked when the information content goes sky high. We learn to put up with this and to try to listen through this haze to pick out the emphasis being placed on the notes by the performer we care about, usually that section we played in, if we did.

These spots on speakers remove that haze, no matter the dynamic peaks or information content. Everything remains very composed, almost polite. And, there is just a train load more information, adhering to it's exactly correct place in the scheme of things.

Here is a link to a local thread, from a fellow responding to some little tiny Fostex drivers in a back loaded horn.

http://www.diyaudio.com/forums/showthread.php?s=&threadid=111830

Here is the EnABL thread in all it's gory detail.

http://www.diyaudio.com/forums/showthread.php?s=&threadid=100399

I have actually treated a pair of CTX 15" pro sound woofers, paired with a JBL baby cheeks horn. The owner, Joe Boecheck a hard numbers EE kind of guy, commented that what he really noticed was that all of the stuff that should not have been available, but was, was gone, but all of the stuff he should have been hearing was clear and available. Seamless integration in tone, micro detail and transient response between the two drivers. The horn needed no help at all.

Bud

 

[c2cthomas]

Hi chops!

For those that a "WTH is it response" perhaps this thread will help. A couple of "newbies" get to try it out - and they posted their impressions. http://www.diyaudio.com/forums/showthread.php?s=&threadid=111830&perpage=25&pagenumber=1

BTW - just missed out on a 100 w/ch amp on eBay -
Kenwood KT-88 with a built in basic eq. Would have been good for driving the the low end.

 

[c2cthomas]

Hmmm - looks as if BudP beat me to the post.

Darn!! That's the 2nd time I've been edged out today!

 

[chops]

I'm going to pass on the whole EnABL thing. The last thing I want to do is paint up and/or mess up $600+ worth of drivers. If they were old junk speakers that I didn't care about, that would be one thing, but they're not.

If I do any kind of treatments, I'll cover the entire baffle (front & back) with sheets of either foam or felt. I just need to find a place that sells them in sheets large enough.

Also, I understand about draping towels over the tops and sides of the 511B horns, but what about the bottom lip? You certainly can't drape towels upwards... Unless you use lots of starch!

 

[Cal Weldon]

Hi Chops,

You only need to damp one of the lips. The sectoral fins couple the other. There is very little ringing in any other part of the horn.

Use wet towels. 🙂

 

[c2cthomas]

Hi Chops!

The local "Super Hardware Store" (take your pick) should sell roofing felt - but it's ugly looking stuff. I'm considering using roofing felt or closed cell foam sheets (used for insulation) to construct a "baffle sandwich" for damping. I'm still playing with a scheme to mechanically isolate the woofers from the baffle but I'm considering using foam / felt / bungee cord arrangement right now.
WalFart sells felt suitable for use as a speaker / baffle cover in the fabric section and has it for a good price.
As per BudP's suggestion someone new to the EnABL thing would want to practice on cheap speakers 1st just to get familiar with the process. You could try it out on your baffles by using masking tape to start with - although the full results are best realized with a "hard shell" type of sound conductor such as acrylic paint as it serves as a more effective transmission medium.
As far as the horn lips go I would suggest the use of a wooden dowel with a towel or felt wrapped around it and some good 'ol duct tape to temporally hold it in place for testing.
Hope this helps!