Printable View
There must be some reason that they were produced for so long but I can?t find much solid info on the internets. My guess would be that the shape at the top of the horn helps disperse what would otherwise be a beaming HF but I have never seen any good measurements.
Marty these 90 degree horns are fascinating and an often overlooked branch of horn evolution. D.G. Blattner of Bell Laboratories received U.S. Patent #1,996,743 on this type of horn in 1935:
ACOUSTIC DEVICE - Google Patent Search
The late A.J. May of RCA also researched these horns and built prototypes. There was at least one production model of 90 degree horn built by RCA of some fibrous material. Mostly it was the Western Electric and later licensed Altec horns that were produced in large numbers.
There were also numerous European 90 degree midrange / high frequency theatre horns built, but they don't appear to use the throat shape to achieve wide horizontal dispersion of high frequencies like the W.E. horns.
I had a plastic pair of Altec 32Bs years ago, but let them slip through my fingers. Never measured them.
TL-221 has the 9849 studio monitor's polar response and as radial horns go, it's pretty impressive and an engineering mini-'tour de force' when one considers its 90? bend and the times it was designed in.
GM
Resurrecting the dead thread :-)
The 32 horns have intrigued me for years. I just came across this PDF with system measurements for monitors including the 9849A. I realize that sales literature is not the best place to find accurate information but I think in this case using it to compare the monitors listed is probably safe. I would assume that the same smoothing and other sales trickery was used across the board. Looking closely it seems the 32B horn is much better at the bottom end of the pass band then the sectorals. That is something I did not expect to see, couple that with better HF dispersion and it is no wonder they were produced for so long. All in all the 32 horns seem seriously under appreciated. As GM said ? a mini tour de force?
http://www.greatplainsaudio.com/vint...leslit_ALL.pdf
Heres a post I found over @ the Asylum. That talks about the 32 horn A/B.
Altec 32A and 32B horns - Salectric - High Efficiency Speaker Asylum
And another from LH.
http://www.audioheritage.org/vbullet...p/t-17241.html
No measurements. But if a "subjective" post has any interest, to me they have a "softer" pattern, a bit wider than an 811, IMHO better choice than 811 for say, a home theater app. Pattern is kinda halfway between the radial horn and an acoustic lens, doesn't seem to have as many phase issues as the lens. I like them.
32B used in Altec A8 reflex box 12" deep,two way system so HF horn had to be 90 degree type.Flange mounted,16"W - 8"H - 8.75"D. 10lbs - 800Hz - H 90X V 40.
It is alleged that the 90 degree bend takes out the casting ring,thus making it gain
popularity with some of our associates,when compared to the 811B.
Forgot to mention 32B also used in 9849 Monitor & 1231 Musical sound monitor
And the 1221A monitor.Quote:
Originally Posted by kinomat
The pair I have ring like a bell when they are not mounted, I can talk into them and hear it. I'm not sure how they will act mounted but I am not worried about ringing. That to me is the easiest thing to fix. The castings leave a bit to be desired though. I will need to get at the throats with a die grinder before they are ready to use.Quote:
Originally Posted by kinomat