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My system include an Onken bass cabinet with an Altec 416-8A. For mid-highs, there's an Altec 288C coupled with an Altec1005B multicellular horn. They are biamped at 600hz at 12db/oct. Also, there’s a JBL2405 tweeter for 13 000 hz and up (6db/oct).My system plays well but I find that the 1005B are directive like an electrostatic speaker. They have a sweet spot when listening. It appears to me that multicellular horns do a really good job but only in tall rooms.
During this weekend, I replaced the 1005B with a 511. No more sweet spot problems. The sound seemed to have more focus.
Bentwoods horns appears interesting but I’m afraid that they will not reproduce high frequencys as the 1005B can. In my system, there’s no low pass filter on the 1005B so they can reproduce highs like they can.
What do you think about the Bentwood horn for an Altec 1005B replacement. Will they be better or i'll do a mistake.
Thanks
Follow Ups:
Hi Marc,The 1005s have a very broad horizontal pattern. I wonder if you may have some relections from side walls causing the sensitivity with the sweet spot? I listened to my nephew's system tonight using 805s, and the sound is smooth and consistent across the width of his living room. Of course the imaging is most precise from the center seat, as with most speakers. Another thing to check is exact placement in relation to the center seat. The imaging will lock in if the distances to both horns are exact, but will begin to fall apart if the distances vary by 1/2" or less. I use a stretched string from the center of the listening chair to check for this.
Multicellular horns usually have smooth dispersion up to about 7kHz., above which the patterns from the individual cells beam progressively. At 10kHz. and above the polar pattern resembles fingers on a glove. This was not a problem in theatres in the old days as they restricted the top end response anyway. This fingering can be heard up close, but I have rarely noticed it from a distance.
The 511 horn concentrates high frequencies on axis rather than sending them out via the axes of the cells as the multicellular does. This might create a situation where more high frequencies are heard in the listening chair from the 511s. As our ability to localize sounds is most acute in the high frequencies, the 511s might seem to image better. I have found that multicellulars do very well though and sound far superior to the 511 overall when they are carefully aligned and reflections from nearby surfaces are controlled.
Thanks a lot for these informationsYes I agree that the sound of 1005B is really good. Do they really goes as low as 500 hz with 288C or it is a good idea to place the crossover point higher ?
Is it a good idea to add some dampening material on the side walls near the horns to cancel the reflections.
You say 511, which 511, the E with the 1.4" throat.?You're not running the 288 into a 511B are you? If so you shouldn't.
511B. I just tried it for the fun with ported wooden made adaptors.
No wonder it doesn't sound good, necking down from a larger driver to a smaller horn is a no-no. I used to have an EV paper from their PA Bible that showed the bad results of doing that---big dips and such in response.
Hi Marc, you should look around for a pair of Edgarhorn 350 tratrix. I am listing mine on eBay tomorrow. They are set up for the 288C and sound better than the 1005 or 511. I don't know how they compair to the Brentwood. Cheers.
The Bentwood's are really nice horns, they have an exponential flare, so they will have a narrow radiation pattern. Reasonably priced too!I am surprised the Multicells do have a sweet spot . Multicells have very good dispersion, but you get a little lobbing fronm cell to cell.
IMO the Altec 511 is the worst horn. The throat geometry is a mess.
Hope this helps......
Yes billi didn't like the 511
I found that multicells have a sweet(s) spot(s) when you are near them to listen.
In my case, they are placed 11-12 feet from my listening position. The sound differ if you are placed in front of a cell or between two cells.
At 12 feet, the lobbing should not be that bad. The only issue is that the Multicells are each an exp. flare.
This means that they will have a slight honk to them Dr. Edgar's tractrix would be a good choice. The only issue here is that the Mulitcell's will have a lower cut-off.
In any event the Tractrix, while directional is an excellent sounding horn. The highs will be better too- the multicell has a disruption at the throat when the sound enters the cells.
I would not throw out the mutiicells though.
You can put a widerange 3" cone speaker on them, use them fromm 300Hz to 1000Hz, and Dr. Edgar's above that.
I will do a little test on this and post it in a day or so.
I will certainly not throw them.I really don't want to add another speaker in my system.
I call my system two way and half because the tweeter is set at 13 000 and up. Adding another speaker means more phasing problems.
The Altec 416-8A goes cleanly to 500- 600hz without problems.
Hi Marc,I have a pair of Bentwood 200 horns with BMS 4592 ND coax drivers. This combo is used from 266 Hz and all the way up, and I do not think that the highs are missing. However, I have not tried to compare the Bentwood horns with any Altecs (or directly with any other horns for that matter), so in this regard I can't help you. Good luck!
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