Bruce Edgar Midrange Horn for 2445

[more10]

Dr.db, are you going to build or buy?

2397 are nice because they are easy to build. But they have separate apparent vertex horizontally and vertically. Vertically the apex is at the mouth. Horizontally at the throat. This means it is hard to pinpoint the sound source.

If buying, the polish biradials seem ok to me. The are almost flat front, just protuding a little bit.

Emilar have made similar horns, a friend of mine has a pair which sounds very nice:


If carpenting maybe Astos horn will give you some inspiration:

[Lee in Montreal]

Plenty of cheap 800Hz horns out there. Emilar EH500 horns can be had for dirt cheap, as well as very high prices, depending where you find them. JBL's 2350 also has a personality. Very dynamic and definitely not subtle. Love them. ;-)



JBL 2350 is theorically a 500Hz horn.

[Horn Fanatic]

Dr.db, are you going to build or buy?

2397 are nice because they are easy to build. But they have separate apparent vertex horizontally and vertically. Vertically the apex is at the mouth. Horizontally at the throat. This means it is hard to pinpoint the sound source.

If buying, the polish biradials seem ok to me. The are almost flat front, just protuding a little bit.

Emilar have made similar horns, a friend of mine has a pair which sounds very nice:


If carpenting maybe Astos horn will give you some inspiration:

If you are able to locate the original 1949 article and drawing for the Bob Smith horn you will notice he calls it a DHS, Distributed Source Horn. The 2397 however, is not a Smith horn and bears little resemblance, as there is nothing exponential about it. I have built many 2397 horns, but my favorite remains the Smith Horn.

As for the "Edgar" horn. Although round Tractrix horn are mathematically correct, IMHO they sound awful. I have built several rectangle Tractrix horns using a 250Hz fc, and they sound much more pleasing.

[Dr.db]

@ Hoerninger:

The Klangfilm Kugelwellenhorn will be less beamy, because it is shorter ? Is it a big difference ? Does it sound as "good" as a 2397 for example ?
If I look at the Kugelwellenhorns from Jabo and the Tractrix-horns from stereolab, there proportions (diameter/lenght) are within 10% equal....


@ more10:

The 2397 won`t produce a precise soundstage, did I get you right? And this is because the top and bottom "plate" is not conical, but parallel to each other ?
I´ve got a pair 2345, they do sound great. But I´d like some wooden horns.
Your wooden horns look very well made, respect! I think I´d prefer a flater horn like the 2397 though...


@ Lee:

The 2350 must be a great horn. But it is a little too big for me. 80cm width is heavy
This horn has no seperation-fins like 2397; does it mean this horn would be more beamy ?


@ Horn Fanatic:

The only difference between smith horn and 2397 I can tell is, that the seperation-fins in the 2397 are a lot shorter. You might help me out explaining the exact differences
Maybe you have a original drawing!?

Regarding bruce-edgar horns: Did I get you right, that round tractrix is crap, but the rectangular like the http://www.soniphase.com/speakersc.html sounds good ?
Are they as nice sounding as a smith-horn ?
Whats the differences you have noticed ?

[more10]

The 2397 won`t produce a precise soundstage, did I get you right?

Correct. I have read it somewhere but cannot find it online, maybe The JBL Story?

I say, build a large rectangular Tractrix!

[Ruediger]

The apparent apex serves a useful purpose when stacking horns. If the horizontal and vertical apices are different, the horn can only be stacked in one dimension. Imagine a PA system where you combine several horns to achieve a certain coverage angle.

It is not the same as the "acustical center".

I do not see how one can determine the acoustical quality of a horn by considering its apparent apices. The sound from all acoustical apices will be in phase with the sound coming from the driver, it does not experience any variation by passing such an apex.

Two different apices will result in what one calls astigmatism in optics, but I doubt that one can hear that. I may be wrong.

I have put a paper covering this subject in the "Technical References" thread in the "General Audio Discussion Forum":

Altec Lansing Technical Letter 262: Coverage of Multiple Mantaray Horns

Ruediger

[sebackman]

Hi,
Try the JBL 2332 if you can compensate in the active or passive filters. Sounds good if the throw is less than 8m. And better if the alu is dampened. I use a bunch of them with 2451Be, 2450SL and also a pair with standard 2451Ti. They are drilled dual pattern so they fit all drivers. Flat front an 12" wide. Thay are CD's so they need EQ.

I use a BSS BLU800 with digital input cards as active XO and also EQ.

Otherwise I think the newer JBL waveguide horns that Ivica is mentioning would be a good choice. There are a few different models and they are all flat front. I'm a bit unsure how they behave below 1k though...

regards
//RoB

[Maron Horonzakz]

The Smith Horn And the JBL 2397 are distributed source horns in the horizontal plain,, Difraction in vertical plain

[Horn Fanatic]

@ Hoerninger:

The Klangfilm Kugelwellenhorn will be less beamy, because it is shorter ? Is it a big difference ? Does it sound as "good" as a 2397 for example ?
If I look at the Kugelwellenhorns from Jabo and the Tractrix-horns from stereolab, there proportions (diameter/lenght) are within 10% equal....


@ more10:

The 2397 won`t produce a precise soundstage, did I get you right? And this is because the top and bottom "plate" is not conical, but parallel to each other ?
I´ve got a pair 2345, they do sound great. But I´d like some wooden horns.
Your wooden horns look very well made, respect! I think I´d prefer a flater horn like the 2397 though...


@ Lee:

The 2350 must be a great horn. But it is a little too big for me. 80cm width is heavy
This horn has no seperation-fins like 2397; does it mean this horn would be more beamy ?


@ Horn Fanatic:

The only difference between smith horn and 2397 I can tell is, that the seperation-fins in the 2397 are a lot shorter. You might help me out explaining the exact differences
Maybe you have a original drawing!?

Regarding bruce-edgar horns: Did I get you right, that round tractrix is crap, but the rectangular like the http://www.soniphase.com/speakersc.html sounds good ?
Are they as nice sounding as a smith-horn ?
Whats the differences you have noticed ?

Greetings Dr.db -

Instead if describing the differences, I'll link the article, including the article for the DHS tweeter. As you can see, out side of the approximate width dimension, the Bob Smith horn is much different than the 2397, also that it was designed for a small format driver. The drawing indicates six separate exponential cells, vs. the short tapered dividers on the 2397. Calculations will reveal that the only part of the 2397 that resembles the Smith horn is approximately nine inches from the throat, the rest was added by Bart Locanthi. You'll also note, that the divider arrangement on the TAD horn follows that of the 2397, only much shorter. My guess is that the first section of the TAD horn approximates the DHS tweeter with a radial exponential manifold section in front of it.

The Smith DHS is just that, six separate sound sources distributed across an arc. If you pass from one side to the other with information put through it, you can hear each individual cell which function as a point source. The main reason I like the Smith horn, is that with his simple calculations a larger version can be designed to accommodate a 1.4" or 2 " driver.

As for the "Edgar" horn? To be blunt. I have heard the round Edgar horn in a few different listening environments, and I stick to my opinion. Round Tractrix horns sound awful, especially with a two inch driver. You may as well be listening to a Hartsfield horn without the lens. The Tractrix horns that I build were for John Tucker of Exemplar Audio back in 2003 and 2004, of which were his design in collaboration with Jeff Marquardt. That horn was used in conjunction with his Tractrix bass horns. The high frequency driver was the GPA 909-8A, and the woofer was the GPA 515-8G. That combination along with the crossover John and Jeff designed made for an awesome sounding system. I haven't heard the Soniphase horn. That chap lives about 20 minutes from me, although we have never met.

Here ya go. Although I used better material, I chose to remain faithful to Bob Smith's plans. I built the horns out of 6mm Baltic birch, and poplar. For the throat transition I was given two throat transitions for the 604 Mantaray horn by Bill Hanuschack at GPA. I cut the back piece down to about an inch square. The horn really needs a proper adapter in my opinion, perhaps a 3/4" thick circular to square transition. I wouldn't think of asking Bill to provide any more back plates, as he would be left with unusable horns.

It really boils down to individual taste. Some people like diffraction horns, and some don't.



http://www.audioheritage.org/vbulletin/showthread.php?27413-Smith-Horn-Article

http://www.audioheritage.org/vbullet...lsted-Tweeters

The Exemplar system I built: http://www.jenalabs.com/images/vsac2008-12-r.png

Good luck,

H.F.

[ivica]

Greetings Dr.db -

Instead if describing the differences, I'll link the article, including the article for the DHS tweeter. As you can see, out side of the approximate width dimension, the Bob Smith horn is much different than the 2397, also that it was designed for a small format driver. The drawing indicates six separate exponential cells, vs. the short tapered dividers on the 2397. Calculations will reveal that the only part of the 2397 that resembles the Smith horn is approximately nine inches from the throat, the rest was added by Bart Locanthi. You'll also note, that the divider arrangement on the TAD horn follows that of the 2397, only much shorter. My guess is that the first section of the TAD horn approximates the DHS tweeter with a radial exponential manifold section in front of it.

The Smith DHS is just that, six separate sound sources distributed across an arc. If you pass from one side to the other with information put through it, you can hear each individual cell which function as a point source. The main reason I like the Smith horn, is that with his simple calculations a larger version can be designed to accommodate a 1.4" or 2 " driver.

As for the "Edgar" horn? To be blunt. I have heard the round Edgar horn in a few different listening environments, and I stick to my opinion. Round Tractrix horns sound awful, especially with a two inch driver. You may as well be listening to a Hartsfield horn without the lens. The Tractrix horns that I build were for John Tucker of Exemplar Audio back in 2003 and 2004, of which were his design in collaboration with Jeff Marquardt. That horn was used in conjunction with his Tractrix bass horns. The high frequency driver was the GPA 909-8A, and the woofer was the GPA 515-8G. That combination along with the crossover John and Jeff designed made for an awesome sounding system. I haven't heard the Soniphase horn. That chap lives about 20 minutes from me, although we have never met.

Here ya go. Although I used better material, I chose to remain faithful to Bob Smith's plans. I built the horns out of 6mm Baltic birch, and poplar. For the throat transition I was given two throat transitions for the 604 Mantaray horn by Bill Hanuschack at GPA. I cut the back piece down to about an inch square. The horn really needs a proper adapter in my opinion, perhaps a 3/4" thick circular to square transition. I wouldn't think of asking Bill to provide any more back plates, as he would be left with unusable horns.

It really boils down to individual taste. Some people like diffraction horns, and some don't.



http://www.audioheritage.org/vbulletin/showthread.php?27413-Smith-Horn-Article

http://www.audioheritage.org/vbullet...lsted-Tweeters

The Exemplar system I built: http://www.jenalabs.com/images/vsac2008-12-r.png

Good luck,

H.F.

HI Horn Fanatic,

Many thanks for the Bob Smith DSH horn "reminder". Owing to its evident large diffraction in vertical plane, I think that Yuichi A290 design would be better solution for the home listening environment, but sure from the point of the DIY realization Smith DSH horn would be much easier to be done.

Regards
ivica

[Dr.db]

Thanks a lot for all your detailed answers


To summarize;

Round tractrix-horn sounds awful. A rectangual tractrix as the soniphase might be good sounding, but still beamy.
But none of you has listened to these soniphase and they don`t seem to be very popular...

Yuichi probably better than 2397 or smithhorn because of less diffraction in vertical plane.
How will I notice the differences ? To be honest, I have no clue how "much diffraction in vertical plane" will sound...

Smithhorn sounds better than 2397... But how about the Westlake Audio version of this kind of horn ??

[Ruediger]

<snip>
...
</snip>
I have no clue how "much diffraction in vertical plane" will sound...
<snip>
...
</snip>

Read an article about "Huygen's Principle" and about "Diffraction at a slot". The latter simply widens the beam. It does not "sound" and it does not add any harmonics, so it does not add distortion.

At the 2380 series of horns the area of the diffraction slot is too small, so part of the sound gets reflected back into the horn, this is what causes the resonances.

At the diffraction slot these horns radiate into quite large a solid angle:

2382 - 120 deg -> 1/3 space
2380 - 90 deg -> 1/4 space
2385 - 60 deg -> 1/6 space
2386 - 40 deg -> 1/9 space

If the slot was longer and thus the slot area was larger, there would be less reflection and still the same diffraction.

Ruediger

[deanznz]

There is a quick and dirty overview of different horn designs here:
http://www.excelsior-audio.com/Publi...WhitePaper.pdf

more in depth articles
Horn Theory: An Introduction part 1 and 2
http://kolbrek.hoyttalerdesign.no/in...p/publications
figure 1 in part 1 is missing but it is the "Original article draft" next link below the above two.

I have done a bucket load of reading lately and the best mid range horn available to the average person (what ever that means) is the K 402 klipsch horn (modified Tractrix). The people who own them have never heard better, same with the people who go to listen. You can hardly find them at all second hand (desperate for cash or downsizing only generally) One catch is they only sell them new with a compression driver, last I heard they were about $1,000 USD each. Another catch (for some) is they are not small, and they aren't sexy either. They are used as part of a system for klipsch pro behind the cinema screen sound systems. Not many people know of them actually. It's the horn in the middle-ish (what's the middle of 4) of the stack over here:
http://www.klipsch.com/behind-the-screen

I have not seen someone attempt to make a diy version, but I know its make up of a mix of 3 horn designs, Tractrix (mouth) and 2 others ..... ha ha, oh and conical is not one of them.

Olaf I have never seen someone reply with an overview of other peoples suggestions before, I think that is very polite and quite a smart idea.

regards,

Dean.

[more10]

I have read it somewhere but cannot find it online

I found it! Smith Selsted article posted by Steve Schell.

This type of horn has an interesting performance characteristic. When listening to it one can not tell precisely from where the sound is coming. This is due to the fact that the focus of the sound source is not the same in the vertical and horizontal planes. The source of sound in the horizontal plane appears to be at the throat of the horn, while in the vertical plane it appears to be at the mouth. This effect is startling in a similarly designed horn for the 500 to 5000 cps range.

[Dr.db]

Thanks Morten for searching the article.


I´ve listened to a JBL 2397 the last days and I really liked it. I´m going to build these in spring.

But actually I´m willing to rebuild the westlake audio-version, also in walnut