Beyond the Ariel

Since so many of you propose to use the old Altec or GPA 15" drivers in a sealed enclosure why don't I see anyone looking at the Altec 411-B version that was made for sealed box alignment? I would imagine that GPA has a copy of that driver. Any reason everyone seems to ignore that for a sealed box alignment?

93 dB efficiency, so not of interest to vacuum-tube fans. Specs also seem to indicate a fairly heavy cone, and a 4" voice coil optimized for high power input.

It looks like a 1970's response to the new era of high-powered transistor amplifiers (Crown DC300 and Phase Linear 700), which were taking out 515's and 416's left and right. This is the market that JBL scooped up and began to move ahead of Altec.
 
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I think if you design and produce a horn to go below the AH425 you should consider the B&C 8PE21 8" driver. Maybe loading down to 100-120 Hz. In my horns they can be crossed as high as 800-900 Hz and embarrass all the horn loaded 15's I have heard.

A 100Hz horn is something I've never done. It seems like a good idea in that you might get a true sub to cross over to it. A 200Hz horn means you are probably going to need a sub and a bass section, but it can be done well. I made a few 160s with 4" throat / 340 combination horns for guys in Australia who had Fane 8M drivers.

I guess the advantage of a 100Hz or 200Hz horn (over a 50Hz horn) is you can get a 900Hz cross over to the upper horn. With 50 Hz horn it is limited to more like 500Hz.
 
Lynn,
Okay I'll accept that efficiency differential. At the same time when I first had those speakers in the Barcelona enclosures they were driven by some old 50's Mac tube amps. If I recall they used 6n6 tubes, been a long time, nothing more than 25 watts I believe. I replaced that with a Mac MA6100 which though not supposed to be a great amp had more than enough power to fill the house with lots of sound especially the bass. Yes the cone may be heavier but if you are using a sealed box alignment and no sub this is a better driver fir low low bass than the other Altec drivers. If your looking to do a two-way system these drivers just work, efficiency only goes so far. Since most guys doing these systems seem to hate using any eq this is not a bad driver to have low bass in a smaller enclosure than you could possibly use with the other Altec drivers in reflex enclosures. I wouldn't discount this 411-B driver off hand. Though the moving mass is increased the suspension stiffness is much lower, the sealed box is a major contributor to a air suspension type alignment.
 
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POOH, do you have any more details or links to the system pictured? It's very similar to a design I have sketched up and just wanted to read more about it.
Cheers
 
POOH, do you have any more details or links to the system pictured? It's very similar to a design I have sketched up and just wanted to read more about it.
Cheers

It's a system I built around 2001? lol Deep bass was four 2235 JBL's push pull per channel up to 60 (sand amp), them twin Altec 416 a side up to 200 to Adamson Kevlar 10" compression drivers (MONSTER compression drivers - lol - less the phase plugs) in Sierra brooks 180 flare tractrix horns to 300 flare Sierra Brooks tractrix horns loaded with TAD 4001 (Parallel 6C33 SET) TADs i think crossed in at 600 cycles - the system sounded pretty bad in that hotel room although dome people said it was the best they ever heard LOL - I build for my room, I'll never lug a system to a hotel room again
 
Do you have a link for this horn?

An Emilar EH153, full size 150 Hz horn built for free space, when used on the floor near a wall they go below 100 cycles with B&C 8Pe21, I now have them elevated a bit and cross in around 120.

Here is an old system when I used them with the 6" aluminum phram 3" exit Emilar EC600. The 8" B&C is better by a wide margin up to 1K - the EC600 actually was nearly flat to 3K in these horns :) They are really good midrange drivers - the midrange horn above is the EH330 horn that also had the EC600's in them

starside.jpg
fhlfront.jpg

The horns measured at the listening space (15 feet - listen closer now) with 8PE21 no back chamber 1/48 smoothing pink noise

5meters48res.jpg

With the back chamber at 12' they are WOW
 
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diyAudio Moderator
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'Sounds' then like you need to figure out how to 'streamline' an Altec Mantaray diffraction horn.
I'm not on the same page yet, give it time maybe, but I've managed to draw the (axial only) version of where I'm at. It's a waveguide only, OS-hypex-(radius-baffle highs)/(secondary flare lows).

It fills the goals of: floor-30 degrees to 500Hz, ceiling-40 degrees to 300Hz, sides off the room walls to 700Hz and on below.

Next moves: consider radial mouth, opening out the corners and closing up the throat.
 

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PooH,

Is it possible than without the rear box : the 1 mm MMS max of this B&C to be the culpritt ? (vs the WOW rear 12' your are talking about after)

What is the back chamber at 12' please ? (rear wall of the sealed cabinet?) : do you have more clearness with it ?

'Like a lot the mid-bass horn : seems shorter than the InlowSound or Volvotreter one (around 1 meter length both, yours seems shorter !)

regards
 
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PooH,

Is it possible than without the rear box : the 1 mm MMS max of this B&C to be the culpritt ? (vs the WOW rear 12' your are talking about after)

What is the back chamber at 12' please ? (rear wall of the sealed cabinet?) : do you have more clearness with it ?

'Like a lot the mid-bass horn : seems shorter than the InlowSound or Volvotreter one (around 1 meter length both, yours seems shorter !)

regards

Rear chamber is tuned to 110 cycles, sealed of course. The horn length is 44.5" throat entrance (modified) to mouth axis with a 4" entrance and mouth is 26" by 46" - it's quite a bit bigger than either of those horns. No culprit with xmax ;)

http://www.kozystudio.com/bu2bu2/middriver/middriver1.htm
http://www.kozystudio.com/bu2bu2/middriver/middriver3.htm
 
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I think if you design and produce a horn to go below the AH425 you should consider the B&C 8PE21 8" driver. Maybe loading down to 100-120 Hz. In my horns they can be crossed as high as 800-900 Hz and embarrass all the horn loaded 15's I have heard.

Very good driver, excellent tone. I currently have a pair doing lower-mids on 20mm perspex/birch OB .
 
So no open cabinet behind the 8", thanks ! (hey 1 mm Xmax = less bigger voice coil = more dynamic & moe détails I assume! :) for this critical range ( was a little disapointed by the mid-bass snap of an Onken 360 with 416-8A (but not its good clarity on voices in its upper range!) ...maybe 40 Hz-700 Hz is too much or the low end of the events...don't know, hard to say...subjective !:dunno:)

Ah, the larger mouth of the Emilar seemed to make it less long on the photograph !
 
So no open cabinet behind the 8", thanks ! (hey 1 mm Xmax = less bigger voice coil = more dynamic & moe détails I assume! :) for this critical range ( was a little disapointed by the mid-bass of an Onken 360 with 416-8A...maybe 40 Hz-700 Hz is too much or the low end of the events...don't know, hard to say...subjective !:dunno:)

Ah, the larger mouth of the Emilar seemed to make it less long on the photograph !

It's a pretty big horn - B&c is sounds very fast dynamic and detailed with great tone. When horn is lifted beyond 1 foot the response below 200 cycles drops - this was some experimenting - they are now coupled to side wall and floor. There is a cabinet behind the 8" it is sealed and tunes to 110 hz
P1250716.JPG
 
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A 100Hz horn is something I've never done. It seems like a good idea in that you might get a true sub to cross over to it. A 200Hz horn means you are probably going to need a sub and a bass section, but it can be done well. I made a few 160s with 4" throat / 340 combination horns for guys in Australia who had Fane 8M drivers.

I guess the advantage of a 100Hz or 200Hz horn (over a 50Hz horn) is you can get a 900Hz cross over to the upper horn. With 50 Hz horn it is limited to more like 500Hz.

I think a straight 100 hz horn that will preserve the midrange is what I need.
What would you build in that size for an 8" driver? Probably best to build it to couple with the floor and have some type of pattern control at least down to 200 hz and clean response to around 1000 hz where it narrows to around 60-70 degrees horizontally. Maybe one that the 340 horn users can order from you? :)
 
I have a couple of shots from a while back of the OB's with Fostex Fe208Ez in place - hope these give the general idea of construction. To be honest I still haven't got the ideal driver in place , the lower driver is a Supravox 285GMF and the upper would really be best as an AER Mk.1 or an Enviee ( Joachim Gerhardt ) for the correct Fs, Q, and sensitivity to work with a 150-200Hz crossover in the series crossover there. The B&C 8PE21 forces the crossover to 350 or 400Hz which is too high.
The OB is based on James Doddington's 'Quasar' OB originally presented on BD-design's forum.

Horn used above, from 700Hz upwards - currently working on the second of a pair of scaled-down A290 Yuichi horns ( 415Hz for 1.4" drivers) - see third picture ( with Aurum G3 ribbon ) .
 

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I think a straight 100 hz horn that will preserve the midrange is what I need.
What would you build in that size for an 8" driver? Probably best to build it to couple with the floor and have some type of pattern control at least down to 200 hz and clean response to around 1000 hz where it narrows to around 60-70 degrees horizontally. Maybe one that the 340 horn users can order from you? :)

A 100Hz flare rate is too low to implement with an accurate Le Cleac'h fibreglass horn so it will have to be plywood probably. But if you are doing a plywood bass horn why not go for 50 or 60 Hz? Then you can get 100Hz from your 8" driver with comfort.