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Do Horn Speakers Tend to be Directional?

62caddy

62caddy

Trust but verify
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I've been experimenting with a pair of Heathkit AS-21s for about a month now - my first experience with horns. Unfortunately placement options are extremely limited in the room in which they are used. Aesthetically it is far more pleasing for the speakers to be placed flat against the wall but I noticed that when I was directly in front of either speaker, the sound improved dramatically. Toeing in each speaker 45 degrees resulted in a similar improvement at listening position - at a major expense of aesthetics.

The horns are Altec 811s and the manufacturer claims 90 degree dispersion but the listening position isn't much more than 45 degrees from center when the speakers are placed flat against the wall. I'd estimate the distance between the center from each speaker is around 13'.

Questions:

Is this behaviour typical of horns?

Is there any way of getting better sound without a major cost to aesthetics?

Does anybody make casters that would not have to be drilled into the speaker legs?
 
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The 811 directivity collapses quite a bit as frequency rises. Only a horn with a different pattern can change that.
 
JBL 2234's (the butt cheeks) are about as non-directional as it gets along with the waveguides used in the Econowaves. They are smooth as silk and have a very large sweet spot
 
62caddy said:
I've been experimenting with a pair of Heathkit AS-21s for about a month now - my first experience with horns. Unfortunately placement options are extremely limited in the room in which they are used. Aesthetically it is far more pleasing for the speakers to be placed flat against the wall but I noticed that when I was directly in front of either speaker, the sound improved dramatically. Toeing in each speaker 45 degrees resulted in a similar improvement at listening position - at a major expense of aesthetics.

The horns are Altec 811s and the manufacturer claims 90 degree dispersion but the listening position isn't much more than 45 degrees from center when the speakers are placed flat against the wall. I'd estimate the distance between the center from each speaker is around 13'.

Questions:

Is this behaviour typical of horns?

Is there any way of getting better sound without a major cost to aesthetics?

Does anybody make casters that would not have to be drilled into the speaker legs?
Click to expand...


The directivity of any speaker or sound radiator gets more directional as the radiator size increases. Thus, a 12" woofer is more directional than an 8" woofer, which is more directional than a 1" tweeter.

Since the effective radiator area of a horn is closely related to the exit size of the horn, you can see how much bigger that typically is than a comparable direct radiator. Thus, horns are typically very directional compared to direct radiators covering the same range.

-k
 
Just wondering if it might help the OP. I have a pair of speakers with horns and I have seen many JBL's with horns that have acoustic lens, those slats that cover the horns, would those not help him with reducing the directivity of his horns?
 
Yes, the 811 has a lot of directivity as Ken has stated.
The separation of 13' is not working in your favor, nor is the low position in the cabinet.
The newer furniture slides make moving anything a breeze.

FWIW, I thought enough of the Altec components that I built my own cabs and put the horns on adjustable sleds on the top of the cabinets. That way I can tow them in and adjust them to fire at my listening position.

Side view of sled:
IMG_0001_1-2.jpg


Sled with 811 and Heil AMT in use (pardon the dust, I was remodeling ):
IMG_0001_1-3.jpg


Best of luck with your speakers.
 
62caddy said:
I've been experimenting with a pair of Heathkit AS-21s for about a month now - my first experience with horns. Unfortunately placement options are extremely limited in the room in which they are used. Aesthetically it is far more pleasing for the speakers to be placed flat against the wall but I noticed that when I was directly in front of either speaker, the sound improved dramatically. Toeing in each speaker 45 degrees resulted in a similar improvement at listening position - at a major expense of aesthetics.

The horns are Altec 811s and the manufacturer claims 90 degree dispersion but the listening position isn't much more than 45 degrees from center when the speakers are placed flat against the wall. I'd estimate the distance between the center from each speaker is around 13'.

Questions:

Is this behaviour typical of horns?

Is there any way of getting better sound without a major cost to aesthetics?

Does anybody make casters that would not have to be drilled into the speaker legs?
Click to expand...

Try placing them 45* inward, and pointed up a tad, like 10*. 811's do have a narrow sweet spot.
 
Brilliant piece of work, WestEnd....but wipe the dust off of them!

Seriously, that was a very elegant solution to the problem.
 
Very ingenious solution Westend. Supertweeter is a great idea as well. A fantastic industrial design effect. :thmbsp:

Times like this make me long for the woodworking talents so many AKers seem to have. :sigh:

I'm not quite sure how I'm going to address the problem but you've all given me some great ideas.

Appreciate all the fine tips gentlemen!
 
One thing that really seems to help is making sure the area between you and the speakers is as free and clear of obstacles as possible (not to mention around the speaker itself, on the sides and in some cases even in back (The latter adds dimension and depth to the sound).

But another thing that's helped me is putting the speakers on pedestals of some kind. Are the horns on yours at eye-level when you're seated in your listening chair/couch/stool/whatever? If not, put the cabinets on tall-enough pedestals so that the horns ARE at eye-level when you're seated. And if you can't move the things that are blocking the dispersion path, then you need to get the speakers up high-enough to CLEAR those obstacles. These things are very-important with most speakers, as is having them at the proper axis (BOTH speakers being at the same proper axis). That's very-important with my Wharfedales. There's a extra layer of rug/carpet under one of my speakers, so I had to add an extra 3/4 of an inch of height to the other speaker to compensate.

Having an ottoman between you and the speakers is a typical example of the kind of thing that messes with the dispersion path. If you can't move the ottoman, then you need to raise the speakers high-enough for the sound waves to CLEAR the ottoman. But proper placement and distancing is extremely-important if you want to get the most out of a pair of speakers. You want each cab to be equal distance from the center-point of your listening spot. If you can't do that, then you're gonna' have a hell of a time trying to hammer out a good soundstage.

Have you ever though about going with one of those "all around the room" kind of speakers?
 
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Hi Greg - yes the horns are pretty much at eye level when seated. I may just toe them inward a few degrees - which won't be optimal but won't overly harm aesthetics - until a better solution can be found.

Frankly it's about as bad a room gets acoustically: Tile flooring, vaulted ceilings and two of the "walls" consist of sliding glass doors while a third wall has a pair of glass paned "French" doors with another single glass door on the other side of the wall. Placement options extremely limited as well.
 
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EV ST350A tweeters and HR90 mid horns have 120 degree and 90+ degree dispersion over most of their ranges. They really opened up the sound of my Speakerlab K's which were rather beamy stock. JR :music::music:
 
62caddy said:
The horns are Altec 811s and the manufacturer claims 90 degree dispersion but the listening position isn't much more than 45 degrees from center when the speakers are placed flat against the wall.
Click to expand...

Do you realize that the 90 degrees are total dispersion? In other words, the 90 is 45 left and 45 right. This description leads me to believe that you are right at the outer edge of their stated dispersion, far from the "sweet spot". Toe them in some.
 
62caddy said:
two of the "walls" consist of sliding glass doors while a third wall has a pair of glass paned "French" doors with another single glass door
Click to expand...

Lots of layered drapes. Horns are accused by some of being "bright". Reflective glass surfaces won't help this at all. Room treatments work wonders.
 
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