RCA Ubangi

[Steve Schell]

I once briefly owned a pair of MI-9462 cabinets that had belonged to their designer, the late RCA engineer A.J. May. A.J. had used them for years to provide sound reinforcement in his home town of Haddon Heights N.J. for the annual Fourth of July celebration in the city park. A.J. told me that one time he attached a watt meter during use and only occasionally saw the one watt indicator lamp light up. I gave the 9462s to an acquaintance who had meticulously restored several big Altec theatre systems and promised to do the same to the 9462s. I fell out of touch with him and fear that he may no longer be earthbound as he was a BIG guy with health problems. The MI-9462s however are eternal...

[Cyclotronguy]

Steve;

If I'm not mistaken Jonathan Weiss of Oswald Mills fame has one.

Kent

[16hz lover]

Steve;

If I'm not mistaken Jonathan Weiss of Oswald Mills fame has one.

Kent

The one he has pictured on his site has the ports butchered off of it, which is a real shame.

[blakehoo]

16Hz lover is in NC & I bought the 3 speakers that Dave is pictured sitting on.
I'm in Henderson NC, now. I was in Charlotte which is closer to Cornelius.
Thought that was odd, so rejoined and posted.

[1audiohack]

Funny how things move around, the one pictured and offered for sale by 16Hz lover is in a truck on it's way to me as I type this. :^)

[blakehoo]

Damn funny all this activity on a 6 yo. thread...
I wanted to compare sonic pressures.
...& as loud as they can get!!

Is this a new center channel for you?

[16hz lover]

the Ubangi is sold and on it's way to Las Vegas now. It was just taking up too much real estate for my 2 car garage system...gotta maximize floor space. When we measured the response on the PC, the mic registered 120db average SPL with music with 110 watts on it.

[Lee in Montreal]

http://2.bp.blogspot.com/_HMkmWL3cTO...0-h/SYSTEM.gif

Those seem to be a diffrent version.

[16hz lover]

http://2.bp.blogspot.com/_HMkmWL3cTO...0-h/SYSTEM.gif

Those seem to be a diffrent version.

once again, they have cut off one side of the ports, I don't get it

[1audiohack]

Is this a new center channel for you?

I don't know what it will be, yet. Just looking at it something in my head says yeah, that just looks right and I'm betting it is. One things for sure, I'm going to see how loud it plays, you just have to!

One of my prosound pals told me of another prosound guy that stood these on end and loaded what became the top port with a 2350 or two and four bullets and toured with them. Crazy.

[blakehoo]

I don't know what it will be, yet. Just looking at it something in my head says yeah, that just looks right and I'm betting it is. One things for sure, I'm going to see how loud it plays, you just have to!

One of my prosound pals told me of another prosound guy that stood these on end and loaded what became the top port with a 2350 or two and four bullets and toured with them. Crazy.

Congratulations! That's exactly what happened to me in 2005!

These 3 are in storage now, but I tried many combinations of drivers with them ...and man they are smooth... You need to use RCA horns with them. They perfectly match the 90 degree RCA horns ...so the combo sounds like its a solid wall /curtain of single sourse sound ...even up close. I like using altec 290 horn drivers with these horns. The 290's have phenolic diaphrams like what were stock with this system ...and of course that lets you approach the lower frequency this horn is capable of reaching.
Three way would of course be best with the combo, but I never got around to choosing a tweeter before I sold the house.

I currently have a home theater style set-up of unmodified Bill H. designed 288/299 "duplex box" altecs' with his 290 based driver box as a center channel. Nobody else knows what this is, but it is basically plug&play and works where I'm at now. You know Bill as the former Altec chief engineer who now runs GreatPlains audio.

What's up with the chopped off ends? I don't know. Once I sealed them off (temporarily) to use altec 411 drivers. The 411's did sound great in the enclosure but those sound good in just about any sealed box. ...so Who knows?

[herki the cat]

....What's up with the chopped off ends? I don't know. Once I sealed them off (temporarily) to use altec 411 drivers. The 411's did sound great in the enclosure but those sound good in just about any sealed box. ...so Who knows?

Well, Mr. John Volkman, RCA Camden Photophone chief engineer designed the seven foot wide MI-9462 Ubangi Horns together with his brother in law, Dr. Harry Olson who developed the differential equations for this horn system. These two giants knew the importance of the Ubangi seven foot width dimension that people have been defeating by chopping off the ends.

This modification ruins the frequency response below the 60 Hz cutoff of the horn flare component. In this mode, the driver sees inductive acoustical impedance. Drivers with heavy cone assembly and FS of 30 Hz may sound great except for the damaged transient response and group delay in this quasi sort of an infinite baffel spectrum.

This design was very carefully executed in a $1,000,000 RCA anechoic laboratory [Been there]. The original Ubangi horn design is capable of excellent performance down to 30 Hz. Ce tout.herki[Quote]

[1audiohack]

Wow, I'll tell ya wow!

With a 9dB parametric cut centered at 153Hz, and a Q of 1.5 it's fairly flat from 35 to 1kHz and pretty good from 40 to 750 Hz. It has that sound I hoped it would have, like a 4550 only bigger and it kicks like a mule.

Functionally in half space with an honest 1.2kW input and a solid output of 120dB SPL at 3M the cabinette scarcely trembles, it is very well built. I'll have to put the laser on it but I would guess cone travel at that volume is maybe 0.375" and for sure less than 0.500" Dangerous fun to be sure!

I must find it a mate! I have a couple of leads. OK I am going back out there!

[16hz lover]

Glad it performs to your expectations. I have located more of them

[herki the cat]

http://2.bp.blogspot.com/_HMkmWL3cTO...0-h/SYSTEM.gif
Those seem to be a different version.

In link:http://2.bp.blogspot.com/_HMkmWL3cTO...0-h/SYSTEM.gifThe image has four RCA MI-9462 Ubangi's & each one has a port side chopped off. RCA Photophone did supply double stacked Ubangi's with a compliment of four MI-9449 LF Drivers. In 1953, RCA had three of these double systems in the RCA Camden Corporate Office Building#2 Demo Room. The three channel Film sound demo was awesome.herki[Quote/]