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Hey... Not sure who you are or what information you have about this speaker cluster... or, if you'll ever see this as it's been like 3 years since you posted but I thought I'd share what I know this. Believe it or not, I actually worked for the company that built this (the exact cluster you have a picture of). It was installed in 1976 a couple years before I worked there however, it was still the talk of the company by the time I was hired there in June of 78. It still hangs in Rupp Arena in Lexinton, KY and is used for every University of Kentucky Basketball game. As far as modern, up to date sound systems go, it's pretty much a relic but honestly, it still rocks after 38 years. I do have reason to believe that the drivers on the horns have been replaced from the original Altec drivers. As far as I know the sub drivers are still the original. It's hard to tell from the picture but the sign on the cluster (as what you have pictured) originally said "BIG BERTHA by Engineered Devices Co. (aka "EDCO") EDCO was a very poorly managed, small electronics plant in Lexington. They went out of business in the early 1980's if my memory serves me right. I left there in 1979. However, the plant was located just a few miles from Rupp Arena. The employees talked about how they actually constructed the cluster on a crane outside in the parking lot and then took it to the arena on the same crane after they tested it all out and pretty much rocked the neighborhood around the plant with the theme from 2001 A Space Odyssey. Best I remember the original sound system was actually designed in New York by an engineer who had worked for the Rolling Stones. The sub cabinets are, I believe Altec A-10's. I don't know what the model is for the horns. It originally was powered by 14 ea. 800 watt Altec Amps. EDCO was some kind of an Altec dealer best I remember. I wouldn't be surprised if the amps have been replaced. It weighs something like 13,000 lbs. One really innovative thing about this sound system is that it's rigging is on a track and it can be moved to the end of the arena and placed over a stage and used for concerts. I attended a concert there not long after Rupp Arena opened and the sound for the concert was this cluster. It was amazing how good it sounded. The Arena is owned by the city of Lexington not the University of Kentucky and the city is planning on renovating it in the near future. I would imagine that "Big Bertha" will then be laid to rest and a new up to date sound system will be installed. However, in its day, she was as good as it got!
The arena array "Big Bertha" and the arena array "UK" aren't in the same venue.
Prove me wrong.
:)
No, that is understandable and reasonable.
If you were going to build a pair of these, then well maybe that's a bit much.
Tom
I am still hung up on this. How could those bass horns keep up with all those mid horns? I guess the bass fills better then I imagine. Imagine the amp stack? Its insain surely larger distribution area would be better. Was it at a world fair or somthing? I guess I will have to google it and find out.
A reduction in output below about 300 hz increases intelligibility of male voice. That's pretty much what that system would do.
My collage had a smaller Altec system above the center of the basketball court. It was a bunch of A5's in a circle with several extra multicell horns added on. It sounded like crap when they played music, but the announcers voice would always cut through the crowd noise.
I cant find anything on big bertha. Maybe it could of been a siren for war time factory.
Must be a big place......
I am not sure, a fellow i work with (Ivan) who posts here occasionally sent it to me. Maybe he will see this and write if he knows the location.
Best,
Tom Danley
"Rupp Arena in Lexington, KY. It's called Big Bertha"
http://photography-on-the.net/forum/showthread.php?t=635736Kyle
Edits: 06/04/11 06/04/11
That is an impressive beast and as you know there is issues just because
of the multi cell etc...
If I was you Tom I would find out where that is and make an offer to update
that stadium
:)
HAHA!
All those beautiful wood multi cells.I cant get my mind around what I am seeing. Thats incredible.Like something out of a science fiction movie.
Wood? I dont think they are wood. They look like standard Altec multicells, just painted tan.
Sweet I need a pair.
Yeah!
It's funny, the 2X15 bass horns are what 8 feet tall, only then does the size of it sink in.
What a difference a day or year or a few decades makes.
Yesterday at a college football stadium at troy college (i think), one loudspeaker, a JH-90, was installed on top of the scoreboard (actually located on top of a building across the street) to serve the entire 30,000 seat stadium.
The difference between the closest and farthest seat was 4dB and during testing, at the farthest seat (700 feet) they were averaging 95dB spl A weighted and "very hifi" according to the installer.
Best,
Tom Danley
http://www.danleysoundlabs.com/
The only question is will that single cab "get over" the crowd noise
Im just curious if a reading of the crowd noise has been taken?
Obviously outside is better then inside a dome.
To get over that crowd noise and be articulate can be a challenge
With the crowd at full roar can you here a guy rubbing his fingers together
in front of the microphone clearly?
Obviously I am kidding on that one :)
I know this seems impossible but these do work differently than other loudspeakers, they radiate as one source without interference.In large scale sound, the acoustic power required is so large that up until now, it can’t be done with anything but a long string or big pile of speakers.
The last 14 years of work has been in finding the conditions to make sources combine in to a single source.
This was easy (more or less) up to the point of needing more HF power than one hf driver can supply. At 20Khz, the wavelength is about 5/8 inch and one cannot place sources close enough (less than ¼ wl) for them to combine coherently like the other drivers do.The solution was a combiner who’s exit radiates the wave front that a single source would have produced but of the power of multiple drivers.
That single part took the longest to figure out, about 4 months and I thought I was beat at one point.The solution, the combiner allowed the JH-90 which was introduced a year ago and a new and an even more powerful speaker to be introduced at a trade show shortly.
The cool part is by having a single radiation lobe, one can aim this at the last row and the the shape of the side of the lobe tapers the loudness, very often the rate of SPL fall of with distance is less than a line source.
At a 30,000 seat stadium installation this week (Troy college in Alabama), a single jh-90 was placed on top of the scoreboard which is across the street from the stadium. There was a 4 dB difference in loudness form the closest seat to farthest seat, much less than normal. At the farthest seat they set the limit at 95dBA slow, which is 700 feet from the speaker and a level most would find LOUD.
Consider the LF section can radiate about 3000 acoustic Wattshttp://blog.mixonline.com/briefingroom/2011/05/11/two-danley-jericho-horns-cover-47000-seats-at-northwestern-university/
http://www.proavmagazine.com/blogs/postdetails.aspx?BlogId=adoptioncurve&postId=98420
This season, they will also be at Packer stadium in Green bay and several other college and NFL stadiums.
I suppose this summarizes it, If you don’t produce an interference pattern, if you can add the drivers constructively then, it takes a lot fewer of everything and that makes a more cost effective solution that in this case sounds better too and is nearly immune to wind effects.
This a demo somewhere where a JH-90 was auditioned next to a well known line array that cost more than twice.http://www.proaudiospace.com/forum/topics/danley-vs-meyer-mina-shootout?commentId=2910192%3AComment%3A112291&xg_source=activity
Best,
Tom
Edits: 06/03/11
fo sure - a better exercise w. K-coupler/simple cheap testbox to work out best baffle and reflector angles to prevent a hole in response. JL did a 28"x13.5"x14" K-coupler for FE206EN regular vent and t-line backwave versions that have a good window of response - that way $300/pair for something cool and no xover. Maybe that SEAS $125 fullrange -?
Edits: 06/01/11
In general, I would say you are crazy to want to build this.
I built about a dozen similar sized dual 15" horns for bass use back in 1978. They sounded quite good, but using 10" or 12" cones for mids sounds better than 15", and there are many low frequency designs that can put out far more more extended low frequency in a much smaller package.
Other than that...
Interesting to see Mark Gander's name on the reprint, I still have a JBL "confidential" enclosure design flow chart detailing how to design ported enclosures that he wrote, which I received in the mid 1980's.
If I build will copy best I can. I do already have midbass design that uses dual 12in in front horn works very good. I just have a bug up my arse to build a reproduction of a JBL or maybe Altec a 2 etc.
But that's okay!
Bass is supposed to sound big. 6.5" is not a woofer size.
But now if you use 6.5" speakers here, they ARE woofer sized. :)
Can you work backwards and tell the cut off freq of the horn?
Homebrew UL 6V6 PP amp,Otari 5050 R2R,Classic Speakers,Pioneer DV-79AVi DVD/CD/SCAD player
Just got the vintage theater horn bug...Maybe most horn owners are a bit off there rockers..
No, not crazy...maybe a bit fanatical. These are very similar to the Altec A4. A friend of mine has a pair of the A4's in his garage, and Frank Sinatra has never sounded so good...
A4 all original? I like this but seems only 1 was ever built might be time for more.
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