Anyone know what type of bass horn this is?

[Horatio]

Hello all:

I recently had a short correspondence with Don Keele, the designer of the first of the Constant Directivity horns, the HR series that EV produced in the 1970's. I had recently acquired a pair of HR6040's for Khorn use, and had a question about the early production versions. I have a pair of HR9040A's that I think are really very nice, albeit quite large. Anyway, Keele did not know the answer to my question, as he had left EV during that time, but referred me to a fellow by the name of Jim Long, and sent the following picture, showing Jim's setup:

My question to this forum is: what type of bass horn is this? It appears that the sides are tappered, and that there _may_ be a slot vent in front. Anyway, I can't quite figure this one's heritage. Anyone on this list ever seen this type of bass horn?

Here's a better shot of the overall setup:

Thanks,

Mike

[Horatio]

One other thing: I just noticed that the EV horns on top appear to have either Altec or JBL drivers on them, with what appears to be some sort of throat adapter. Anyone recognize those drivers?

-M

[Colin]

sweet spot indeed!

[jacksonbart]

a loud one

[Edgar]

That's a Ray Newman design known as "H11". Jim Long is the one to ask about them as I believe he has the only pair in existence. Mr. Newman perished several years ago, and left only incomplete notes and sketches in addition to the two cabinets, copies of which Mr. Long has been kind enough to provide to me. I have a Hornresp model based upon assumptions that I had to make about many of the measurements -- as I said, the notes that Mr. Newman left are incomplete. I would be willing to make the information that I have available, but only if Mr. Long approves.

Greg

[Horatio]

Loud one's, indeed!

Greg: you hit it on the head. I just got an email from Jim Long, confirming those H11's, and Newman's sketches of same. The drivers are probably TAD 2001's. I think Jim eventually settled on those, and I think those are 1" throats, so, it all makes sense- he only needed them to cover to 500 hz.

Cool thing about those H11 bass horns is that they showed, in the 1990's, what Delgado and Klipsch found with the Jubilee- that folding in a single plane and splay angle makes all the difference in how high you can get 'em to go.

Thanks!

[Edgar]

Cool thing about those H11 bass horns is that they showed, in the 1990's, what Delgado and Klipsch found with the Jubilee- that folding in a single plane and splay angle makes all the difference in how high you can get 'em to go.

The H11 only goes down to about 70-80 Hz, however, compared with around 40 Hz for the Jubilee.

THe H11 would make an interesting DIY project. Each contains a single Electro-Voice DL10x driver, though an EVM10m or Klipsch K41m would be essentially equivalent. It's a basic "W" fold design, and appears to be fairly simple to construct. It would be a good match for many curved-front radial HF horns like the HR9040a shown in the photo.

[Chris A]

The H11 only goes down to about 70-80 Hz, however, compared with around 40 Hz for the Jubilee.

Greg,

If you are referring to the Fc (cutoff frequency) for the Jubs then you are essentially right. However, their -3 dB point in-room (if placed in good corners) is about 33 Hz, essentially the same as the Khorn's -3 dB point. The lighter-green curve shows the measured in-room response of a Jub, the red curve is the SPUD-only, and the dark green curve is my EQed room response for both.

Edited April 23, 2014 by Chris A

[Colin]

very coo! EQ makes a big difference, what is SPUD?

[Chris A]

what is SPUD?

Here is a thread on the DIY SPUD.

I've got two in my room, one behind each Jub, which allows the Jubs to be pushed out into the room about a foot or so and thereby dramatically increasing K402/TAD 4002 imaging performance.

Simply stated, the SPUD is the best-value DIY subwoofer that I've ever seen: about $220 (ea) for materials/drivers. They are excellent for integration with Khorns/Jubs, extending their lf performance about an octave (down to ~17 Hz). They are seamless when used with Jubs and Khorns.

Chris

[Edgar]

Interesting. Danley shows the SPUD to be a lot flatter than that below 60 Hz. Where is your SPUD located in your room? It looks like there may be some significant room interactions in your frequency response graph.

EDIT: Just read your other post regarding placement of the SPUDs behind the Jubilees. Perhaps orienting the SPUD mouth differently would change some of those peaks and valleys. Might be worth experimenting.

[Chris A]

Greg,

Actually, I'm very happy with them where they are at. I tried about 3 other orientations in-room, but the increased imaging performance of the K402s really got my attention. BTW - pushing the Jubs out into the room a bit was a suggestion from Roy D. He was dead on: the change in imaging was dramatic. Note that I've got a mantle and hearth between the Jubs that interact with the imaging a bit. The SPUDs behind the Jubs form a natural "false corner" for the Jubs to move out into the room and support the lf end more than if they were sitting out in the room--about 18" from the front wall now.

I did the EQ job seen in the graph--which took the better part of a day to complete--alternately using REW, an ECM-8000 microphone (used iteratively in multiple room positions), a DEQ2496, an EV Dx38 (for the Jubs), and two XTi-1000s (one each driving the SPUDs-one channel each SPUD driver) to iteratively transfer the automatic EQ device results to the active crossovers. The composite performance was achieved without using the DEQ2496 device in the final configuration.

That exercise really changed the character of the Jubs/SPUDs and led to greatly increased listening satisfaction, IMHO. Getting the lf tamed in the 20-100 Hz band was a big deal in the final analysis. The Jubs/SPUDs don't have a "corner-horn sound" anymore - just a neutral, clean, powerful sound.

Chris

[jwc]

Chris.

That jube curve has a loss of energy at 200+ Hz. Could this be the room?

jc

[Chris A]

Yes,

JC - there were a lot of miking issues, but strangely, I found that as the frequencies got below 120 Hz, the measurements in the area of the listening positions stabilized in-room. This was a big surprise for me. I guess another way of saying this is that the room modes seem to get closer together in freq. as you go higher, and are more sensitive to the microphone position. In some cases, movements of millimeters could change the response by several dB above about 150 Hz, and anything above that point, I didn't try to correct. I stuck to the anechoic PEQs that Roy did in the chamber (although I pulled the ~180 Hz PEQ filter down a bit more).

I only tried to correct the obvious "minimum phase" peaks and not try to boost any valleys/troughs. This approach worked very well. I did wind up having to move the microphone into about 5 different sequential positions--using both the DEQ2496 time-averaged pink noise cross-correlations and then checking using REW to show resultant EQ response using sine up-sweeps. The resultant from the front-row listen area, at ear height while seated, is what you actually see in the plots. I used the most common listening positions as the final vote in where I set the EQ response.

Chris

[Chris A]

I found the Linkwitz site on "Loudspeaker Design", and remembered the so-called "Schroeder frequency" (I think it is pronounced "shrader" with a long "a").

The formula is: f_s = 2000 ( T₆₀ / V )^1/2 [Hz, s, m³]

Here are the values that I used for my room:

V = 152 m^3

T₆₀ = 0.38 (approximate room reverberation time, based on REW-measured results in-room)

My listening room's Schroeder frequency turns out to be ~100 Hz.

This would explain why I was able to do the in-room measurements below 100 Hz, i.e., in the "sparse mode region" below the Schroeder frequency.

Most folks' listening rooms are probably not 152 m^3 in volume, so the Schroeder frequency would be higher than this. If you use the following values for room dimensions, you will see that the typical "sparse mode region" starts at a higher point. Here is a more typical listening room case:

W = 20', L = 15', H = 8'; V = 68 m^3; f_s = 203 Hz.

That would be the approximate break-point frequency below which you could probably get reasonable in-room microphone measurements if you use multiple measuring positions.

Just FYI.  

Chris

Edited September 3, 2015 by Chris A

[PrestonTom]

"......

and remembered the so-called "Schroeder frequency" (I think it is pronounced "shrader" with a long "a").

...."

OT: Nope, it is prounounced with a long "o"

[Chris A]

How do you pronounce Schröder?

"Manfred Robert Schröder (12 July 1926 – 28 December 2009) was a German physicist, most known for his contributions to acoustics and computer graphics. He wrote three books and published over 150 articles in his field.^[1][2]"

[gibber]

Greg: you hit it on the head. I just got an email from Jim Long, confirming those H11's, and Newman's sketches of same. The drivers are probably TAD 2001's. I think Jim eventually settled on those, and I think those are 1" throats, so, it all makes sense- he only needed them to cover to 500 hz.

Very inviting photo of a comfy-looking setup. The white whales look great. Don't know why Jim Long's HR9040A horns don't have the central fin ... where the white whales ever sold that way or did he take them from the production floor before the center brace was glued in? They look better this way.

There's not much below 500Hz in the "A" versions of the 90 or 60 deg whales. For two way use, the early producion version without the "A" allows lower cut-off with the trade-off that the diffraction slot is acting more prominently. HR6040 or 9040 have the 1.5" high but 4" wide sticker (the "A" versions have the upright sticker)

For those that are sensitive to apparent apex shift and/or distortion effects associated with narrow slot fed CD expansions: HR6040A sports the most gradual opening and in my view is the best of them all by a narrow margin (plus added WAF - it's 7" less wide than HR9040A).

Cool thing about those H11 bass horns is that they showed, in the 1990's, what Delgado and Klipsch found with the Jubilee- that folding in a single plane and splay angle makes all the difference in how high you can get 'em to go.

Another way of expanding bandwidth (both upper and lower freq) is to follow Keele's 1973 AES paper and go for lowest Qes drivers you can find. DL10X as used in the H11 are a good starting point. These drivers are actually used for midrange typically and this path, if taken to the extreme, can lead you to finding even better drivers. Why not go for pro mid ranges and get more low extension while doing so, just as Keele's TSP-based write-up of classic horn theory predicts. Avoid highish Fs, though.

Beyma 102Nd (or 122Nd if space allows 12") offer Q values below 0.1, but there are others and most are cheap enough if anyone just wants to give it a try.

greetings !

[Edgar]

Don't know why Jim Long's HR9040A horns don't have the central fin ... where the white whales ever sold that way or did he take them from the production floor before the center brace was glued in? They look better this way.

I've seen them both ways, and I don't know when the change was made. The pair that I have does not have the center brace.

There's not much below 500Hz in the "A" versions of the 90 or 60 deg whales. For two way use, the early producion version without the "A" allows lower cut-off with the trade-off that the diffraction slot is acting more prominently. HR6040 or 9040 have the 1.5" high but 4" wide sticker (the "A" versions have the upright sticker)

Somewhere I have response graphs from the 9040 series, but I cannot locate them at the moment. I recall EV stating that they loaded down to around 300 Hz, with a recommended crossover at 500 Hz. But I also seem to recall some anomalies in the response between 500 and 700 Hz, leading me to conclude that 700 Hz might be a better choice. Mine are not in use at the moment, so I cannot comment beyond that.

For those that are sensitive to apparent apex shift and/or distortion effects associated with narrow slot fed CD expansions: HR6040A sports the most gradual opening and in my view is the best of them all by a narrow margin (plus added WAF - it's 7" less wide than HR9040A).

The 9040A is approximately the same width and depth as the K402; about 6" less in height. But that curved front makes it difficult to integrate into a cabinet of any reasonable shape.

Greg

[Edgar]

Somewhere I have response graphs from the 9040 series, but I cannot locate them at the moment. I recall EV stating that they loaded down to around 300 Hz, with a recommended crossover at 500 Hz. But I also seem to recall some anomalies in the response between 500 and 700 Hz, leading me to conclude that 700 Hz might be a better choice.

See page 25 of Keele's paper.