135Hz Segmented Horn Midbass Build

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Hi John, Jennifer here....I have been watching this thread with interest. You have seen my 18" JBLs and we both know they just gonna not do the speed and impact thing right, when going up to blend into my 2" 2446 driven upper horns. Though the system will not likely be actually built until next year, I think I am going to have to think seriously about these mid bass horns to bring the energy needed under the tops, and above the bottoms, as forcing that big 18" will have some deficits..

to the rest of you, John knows about the project I'm cooking up....to fill you in its going to be a dedicated TV sound system, Left Center Right. Because its movies and not a full time music system, I am going to be using stock 2446 2" compression drivers that I was able to get at the right price with 2365 horns. No need for Truextant Be in these for old movies and TV. Horns are JBL Don Keele designed 60 x 40 dispersion bi-radials from the previous generation pro-cinema series. As per John's advice, I am layering the fiberglass with paper, glue, and joint compound, as this will deaden out the glass "ring". In the same deal I got a set of 3, 2241 18" drivers....There are great from the mid 30s up into the hundreds with slam and impact, but expecting them to blend into to horn at 500 is taking it a bit far. The factory did these as 2 way for 20 plus years in their cinema systems, but that 250 600 octave was always lacking just a touch of speed and impact in them... One of these mid bass horns with be PERFECT as a 'go between' to make a 3 way.

I HAVE been working on improving the frequency response of the upper horn/driver...Once that is done I will start thinking about bass enclosures, and looking for drivers that will work with this mid-b horn... This is a back-burner project, so please don't ask for photos yet....I'm still getting materials to start fixing the horns with paper layers, and right in the thick of making network experiments! Long way to go!!!

For a music system, nothing in my listening experience has been finer than John Inlow's paper horns...Just VERY simply beautiful music in his listening room, ....after this TV system is up and running, I AM going to do a pair! Honestly, I got spoiled hearing John's horns and must own some before leaving this Earth for whatever celestial music there is elsewhere...

nice to see these mid bass units....THANKS for showing the build!
 
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Ask John to show you his approach to BASS HORN.....
they will knock your socks off...

Hello Jennifer! Nice to see you're on DIY Audio. :)

I've got the spiral 15-A horns (stereo pair) up and running, and have invited Pat Hickman to bring his 2A3 amp over for an auditioning adventure. Perhaps you'd like to join the party? If so, I'll contact you when the event is structured.
 

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Thanks Javad.

Very insightful.
The size tradeoff is certainly one I'm accounting for, especially in light of the wife's view.
Sounds like the horn has some coloration you aren't used to. And sounds like the gain in transient speed is there but maybe not worth it based on other tradeoffs.

Yea, I'm struggling frankly with the trade off, if I was limited to a 10-watt tube amp then the horn would be a no brainer. I'm going to build them just to say I did and really spend some time with them, afterall this is a learning journey for me as much as anything.

BTW, why did you opt for a vented box for the direct radiator? Isn't sealed going to have better speed? FWIW, my drafted design includes double 10" per side in sealed boxes, 80 to 500Hz or thereabouts. Beyma 10G40.

A block off plate is easy to do, the issue was in the modeling that the sealed box barely went below 150hz.

Are you planning to continue to listen to the mid bass horns and tweak to see if you end up liking them better?

Regards
Horacio

Definitely, my other Radian 745CD is arriving today so I can listen to a stereo pair.

Thanks!
Javad
 
Hello Jennifer! Nice to see you're on DIY Audio. :)

((( Been a member here for many years....Mostly lurking around..))))

I've got the spiral 15-A horns (stereo pair) up and running, and have invited Pat Hickman to bring his 2A3 amp over for an auditioning adventure. Perhaps you'd like to join the party? If so, I'll contact you when the event is structured.

AH YES, I remember seeing those on the workbench, and hearing the first one roughly finished still in the garage...THIS will be fun. Keep me informed... I am setting up some of my custom built 100% nickel Cinemag multi winding transformers to drive 2 of Pat's stereo amps in bridge mode, ..He has more than one running now, so it IS time to have some fun with them.
 
... I'm going to build them just to say I did and really spend some time with them, afterall this is a learning journey for me as much as anything.

...Definitely, my other Radian 745CD is arriving today so I can listen to a stereo pair.

Thanks!
Javad

Hi Javad. I'm glad you're building a stereo pair to compliment the Radian horns. Perhaps the next mid bass horn will be fabricated to exact specs and perhaps it will measure (or sound) different than the first horn--who knows? You might be in for a treat. I can tell you that the mid bass is for system tone and snap/punch. It's the 450 hz high frequency horn that carries the brunt of the frequency load and makes those mid bass horns shine.

Best of luck, and may the audio gods be with you in your quest for knowledge and nirvana. :D
 
AH YES, I remember seeing those on the workbench, and hearing the first one roughly finished still in the garage...THIS will be fun. Keep me informed... I am setting up some of my custom built 100% nickel Cinemag multi winding transformers to drive 2 of Pat's stereo amps in bridge mode, ..He has more than one running now, so it IS time to have some fun with them.

Sounds like you have an interesting experiment in the works--hope it pans out.

I've been dialing in the 15-A horns for several weeks--just added the JBL 2404 baby butt cheeks to augment the top octave. It's quite the project, and keeps getting better and better as I learn how to manage the challenges.

Look forward to a visit with you. :)
 
The horn sub is up on the front wall loaded with JBL 2242 - the horn splits to two corner loaded paths each 21 feet long then into thr concrete corners. There is also a rear corner loaded BR sub tuned low (shelved and delayed) with twin JBL 2242. The bass is twelve 15's.

Impressive description! Have any pics? I'd love to see what you've been up to--a man after my own heart!
 
Impressive description! Have any pics? I'd love to see what you've been up to--a man after my own heart!
:) I'm working on rebuilding the upper midrange and treble and should post a picture in a couple of weeks. The sub horn has been here for years.It's built in. I've had several attempts at getting the 50- 120 range horn loaded but none ever beat out a mass of 15's in my room. I know it can be done but too big for the room - the upper bass mid horns are nearly 5 feet deep with the back chambers. I use the B&C 8Pe21 - nice driver
 
:) I'm working on rebuilding the upper midrange and treble and should post a picture in a couple of weeks. The sub horn has been here for years.It's built in. I've had several attempts at getting the 50- 120 range horn loaded but none ever beat out a mass of 15's in my room. I know it can be done but too big for the room - the upper bass mid horns are nearly 5 feet deep with the back chambers. I use the B&C 8Pe21 - nice driver

Yes we'll need pics if you're going to describe such a system! :D

Javad
 
Javad,

As you know real estate in the Bay Area is expensive, and you may want to consider building UP for your BASS. Maybe a stack-up of:
-PPSL: Push-Pull-Slot-Loaded woofers
-SLOB: Slot-Loaded-Open-Baffle woofers

Both offer vibration reduction from counter-force driver construction, and some directivity control from the slot-loaded wave launch. A floor-to-ceiling line array of woofers can smooth many room bass modes.
-PMA! built the greatest SLOB I have ever seen. SLOB is even good enough for Nelson Pass.
-Scott L and djk have worked on PPSL.
-Monoliths of Worship for baby pictures.

A woofer stacked line array positioned in the front corners also gets positive reviews, but without counter-force construction you have several pounds of cones flapping around. Rock-and-Roll Woofers.

I believe you would need a midbass horn which reaches down to ~60Hz before you could optimally integrate a heavily equalized woofer swarm positioned around your room floor. A pair of front floor-to-ceiling woofer line arrays can smooth many room bass modes with modest floor space and simplier equalization starting at 100-140Hz (8' wavelength) .
 
I was going to try a transmission line variation with 6 15" Dayton OB-15 per cabinet, 3 on each side, 3 opposing the other 3. It would have staggered drive along the length to flatten out the 'one driver location' issues with TLs and it would not have the wavelength cancellation of near open baffle woofers. I tried some experiments with side walled open baffle setups and was not at all happy with the front and back coupling/cancellation. More wall size, and more driver is better, and PPSL or SLOB array is probably the very best way to implement this.... I only have 12 of these woofers, 6 per channel. If doing a PPSL or SLOB array, I think more than 6 would be necessary, at least based on what I heard from side walled open baffle experiments,....I think 10 would be enough, and I do not own that many. Am I wrong? can we do an effective SLOB array with only 6x 15" drivers per array?...and with what size wings? I am a VERY strong advocate of vibration cancellation via opposing woofers..THAT works, and can say from experience, it is simply amazing to touch a cabinet when playing LOUD bass, and feel absolutely no perceptible vibration.
 
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Correction to above post....
"Am I wrong? can we do an effective SLOB array with only 6x 15" drivers per array?"
Should say:
"Am I wrong? can we do an effective PPSL or SLOB array with only 6x 15" drivers per array?"

I suggest you ask member PMA! On his thread "My DIY Horn Setup". I actually asked him this on post #200, and his answer on #201. He has more experience than just building his own, as he mentions he built at least another one for a friend. From his answer I take the answer to your question is "it depends", as usual :). His take seems to be it depends on your room size and how loud you want to play and how clean you are demanding it to be at the higher volumes.

Since you have the drivers, why don't you build two identical prototypes in a way such you can use 6 or 8 per side, or more if you like, but so it will work properly when it has 6 mounted. A modular approach. Then try one channel with 6 and more and assess if for your needs in your room 6 is enough.

And please post your experiments and journey. I am very interested in these concepts even though now I'm working on the upper 3 ways. My two DIY subs are standard direct radiator in sealed boxes and can go louder than what I need and clean (at least as far as direct radiators is concerned these are considered clean), but there must be something beyond loud you guys are after with that many drivers per side...6x15" per side and wondering if it's enough...it's an economically inefficient design, so there must be a sound quality advantage to it that makes it worth it and that is what has me intrigued.

Sorry Javad we derailed! Looking forward to an update from this weekend!:D
 
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