There is a lot of interest in high-fidelity constant-directivity loudspeakers these days. I'm very happy about that because I think it's the right path for making the most satisfying home sound system. I've been building my hifi loudspeakers this way for over 30 years.
I wanted to "put a bug in the ear" of others of you that are as interested in this approach as I am. Don't stop at a matched-directivity two-way or a dipole. If you have a chance, also try a constant directivity cornerhorn. I've heard great dipole speakers and I've heard great horn/waveguide speakers but I must say that nothing even comes close to a set of constant directivity cornerhorns. The improvement is that stark.
The whole idea is pretty simple. The woofer is close enough to the walls that they don't cause any self-interference. If they're closer than 1/4λ, there isn't a reflection. It's more like a ground plane, all three surfaces the floor and both adjacent walls being acoustically close to the source. So the source radiates into eighth-space and you don't have any trouble with early or late side or rear reflections - there aren't any. The sound traveling along the walls arrives at the same time as the direct sound without reflection. The only reflections come from opposing walls.
Naturally, the midrange and tweeter cannot be this close to the walls. The acoustic scale makes it impractical at higher frequencies. So I think it is best the midrange and treble sources be horn/waveguides that provide constant 90° radiating angle to match the room corner wall angle. The midhorn needs to be large enough to provide pattern control, and it can be snuggled close enough into the corner that the walls can act as extensions at the low end. Up high, it needs to provide pattern control to keep the coverage angle within the walls. Same with the tweeter.
The thing with waveguide loudspeakers that pair a direct radiating midwoofer with a constant directivity horn is they usually only provides constant directivity in the top decade, about 1/3rd of the audio band. This is the most important region to provide constant directivity, in my opinion, because it's where all the detail is. But the next decade below that is where all the body of the music is, the vocals, instrument fundamentals, most everything, actually. This is where the constant directivity cornerhorn rules.
Not every room has the right corners to be able to take advantage of this setup. So not everyone can use constant directivity cornerhorns. But if you have the right corners, nothing beats this setup, in my opinion. A properly designed constant directivity cornerhorn system provides constant directivity all the way down to the Schroeder frequency, where multiple subs can be used to provide uniform room response. You can actually achive constant coverage of the entire audio band throughout the room this way.
I wanted to "put a bug in the ear" of others of you that are as interested in this approach as I am. Don't stop at a matched-directivity two-way or a dipole. If you have a chance, also try a constant directivity cornerhorn. I've heard great dipole speakers and I've heard great horn/waveguide speakers but I must say that nothing even comes close to a set of constant directivity cornerhorns. The improvement is that stark.
The whole idea is pretty simple. The woofer is close enough to the walls that they don't cause any self-interference. If they're closer than 1/4λ, there isn't a reflection. It's more like a ground plane, all three surfaces the floor and both adjacent walls being acoustically close to the source. So the source radiates into eighth-space and you don't have any trouble with early or late side or rear reflections - there aren't any. The sound traveling along the walls arrives at the same time as the direct sound without reflection. The only reflections come from opposing walls.
Naturally, the midrange and tweeter cannot be this close to the walls. The acoustic scale makes it impractical at higher frequencies. So I think it is best the midrange and treble sources be horn/waveguides that provide constant 90° radiating angle to match the room corner wall angle. The midhorn needs to be large enough to provide pattern control, and it can be snuggled close enough into the corner that the walls can act as extensions at the low end. Up high, it needs to provide pattern control to keep the coverage angle within the walls. Same with the tweeter.
The thing with waveguide loudspeakers that pair a direct radiating midwoofer with a constant directivity horn is they usually only provides constant directivity in the top decade, about 1/3rd of the audio band. This is the most important region to provide constant directivity, in my opinion, because it's where all the detail is. But the next decade below that is where all the body of the music is, the vocals, instrument fundamentals, most everything, actually. This is where the constant directivity cornerhorn rules.
Not every room has the right corners to be able to take advantage of this setup. So not everyone can use constant directivity cornerhorns. But if you have the right corners, nothing beats this setup, in my opinion. A properly designed constant directivity cornerhorn system provides constant directivity all the way down to the Schroeder frequency, where multiple subs can be used to provide uniform room response. You can actually achive constant coverage of the entire audio band throughout the room this way.
I showed 'em to SWMBO and asked "Honey - what do you think of these?" Her comment - "aren't those a little big for us" (meaning her). 🙄
I will need to devise a method of making them look acceptable - How well do you think they would work as a base for some potted plants etc.? 😀😀😀
I will need to devise a method of making them look acceptable - How well do you think they would work as a base for some potted plants etc.? 😀😀😀
Welllllll - I explained to SWMBO that there ARE two speakers - a pair - to a set, and she said "oh - well in that case they look very nice. They sort of remind me of Klipsh speakers (her father had a set of those)" 
Soooooooooo - maybe I can start to do a bit of planning with these.
Can I find anyone out there that is willing to just put me outta my misery and get it over with???
Soooooooooo - maybe I can start to do a bit of planning with these.
Can I find anyone out there that is willing to just put me outta my misery and get it over with???
Last edited:
~~~~~~~~~~~~~~~~~~~~~~~Snip~~~~~~~~~~~~~~
Can I find anyone out there that is willing to just put me outta my misery and get it over with???
I would never ask a question like that, as my computer's inbox would be jammed packed in no time!
😀
I started with Corner Horns and wish I still had them.
Best Regards,
Terry
Well it is the weekend and things slow down a lot around here when people aren't visiting the forums while they are at work - so not to worrry. 😀😀😀
Interesting. Better than dipoles hey...
So the walls effectively become mid-low horn. Would placing a normal cd speakers like econowave in the corners satisfy the requirements?
So the walls effectively become mid-low horn. Would placing a normal cd speakers like econowave in the corners satisfy the requirements?
You've nicked my diagram (page 13)😉
I think you are right to point out that most Constant Directivity systems are really only CD from 500 or 1000 cycles up. These days there are also a lot of "low HOM" designs that have smooth directivity but aren't really CD.
Placing a sytem tightly into the corner can remove all adjacent boundary or Allison type effects but room standing wave effects remain. You have to ask whether that placement is optimum, and optimum has to be viewed in terms of LF response at the listeners position.
Another aspect that I'll have to think about is, if you place a CD system in a 3 plane corner that roughly matches its directivity, have you lost the benefit of constant directivity? It seems any system with wide and uncontrolled directivity placed into that corner would have the same directivity. Does the system become "omnidirectional" in 1/8th space?
David S.
When one simulates a corner in Hornresp (not just using the eighth-space option, but simulating the corner as a conical horn one gets corner-loading up to about 1000 Hz with a 5"er in direct contact with the wall.
Absolutely - a multisub configuration should be employed below the Schroeder frequency, where possible. That's described in the last few pages of the whitepaper, along with several references for further study.
By the way, I want to tip my hat to you, and give thanks. One of the references at the end of that document is yours.
Smith, Keele and Eargle, "Improvements in Monitor Loudspeaker Design", J. AES, Vol. 31, No. 6 (1983 Jun)
One thing about cornerhorns, they really tuck away. You can put a whole lot of speaker in the corner without seeming like it takes over your room.
We'll have to ask Mr. "Atec Best" about that. He has a pair of huge double 15s just built that are going into the corners of his living room. Can't what to see the photos. 🙂
Maybe it's been answered elsewhere, but I curious about the imaging aspects of a corner horn. It's clear that reflections will be reduced, but how much do those reflections go toward forming an image. Does the corner placement flatten the image impression? How much are front wall reflections responsible for apparent image depth?
sheldon
sheldon
One of the things that makes the cornerhorn so magical to me is its uncanny imaging. I remember back when I first started building speakers this way, I thought the reason they sounded so good was the uniform coverage and reduced reflections. I didn't really think about the self-balancing normalization from crossed-axes until much later. But I think that's a big part of it, because they really work best in rooms where the listeners can be placed just behind where the forward axes cross. There's more about that in the paper linked in the first post on this thread.
Toe In
Hey Wayne, what experience do you have with corner horns and toe-in? I've heard corner horns that I liked a lot, but my problem is toe-in.
In my room it would be necessary to roll the speakers in a bit to put the listening position where I like it. 45º would put me too close to the speakers - to far into the room. To sit just behind the cross point the speakers would need to be toed-in about 60-65º, not 45.
Any thoughts on that?
Hey Wayne, what experience do you have with corner horns and toe-in? I've heard corner horns that I liked a lot, but my problem is toe-in.
In my room it would be necessary to roll the speakers in a bit to put the listening position where I like it. 45º would put me too close to the speakers - to far into the room. To sit just behind the cross point the speakers would need to be toed-in about 60-65º, not 45.
Any thoughts on that?
Some rooms just don't lend themselves to a cornerhorn arrangement. I generally stick with a more traditional matched-directory two-way speaker when I setup in a room that won't support cornerhorns for one reason or another. Some still respond to the crossed-axes setup, but some don't.
I will say that the rooms that allow the crossed-axes setup always tend to sound better to me. They allow a wider sweet spot, and for whatever other reasons may come into play, they just sound better to me. Usually the ones that don't allow this setup, have issues that are hard to work with, like the room is small or has an awkward layout. Those are tough no matter what else is going on.
In your case, do you have room to bring the speakers in closer together and cross them in front of you? In other words, is the room large enough but the wall you're facing is longer than the walls to the sides? If that's the case, I'd bring the speakers inboard a bit and cross the axes and see how that sounds. It won't be a cornerhorn setup, but it will still provide good imaging.
I will say that the rooms that allow the crossed-axes setup always tend to sound better to me. They allow a wider sweet spot, and for whatever other reasons may come into play, they just sound better to me. Usually the ones that don't allow this setup, have issues that are hard to work with, like the room is small or has an awkward layout. Those are tough no matter what else is going on.
In your case, do you have room to bring the speakers in closer together and cross them in front of you? In other words, is the room large enough but the wall you're facing is longer than the walls to the sides? If that's the case, I'd bring the speakers inboard a bit and cross the axes and see how that sounds. It won't be a cornerhorn setup, but it will still provide good imaging.
A two-way speaker (even CD horn/waveguide) won't work beyond the point where the midwoofer becomes acoustically distant (i.e. over 1/4λ away) from the walls. At that point, it will have a series of self-interference notches in response. Here's why:
It's all a matter of acoustic scale.
At low frequencies, the woofer is within 1/4λ of the walls and there is no self-interference from reflections. There are room modes, standing waves between opposite walls, but that's below the Schroeder frequency, under 150Hz or so. From this point up to where the woofer is 1/4λ away from the walls, the corner forms a giant waveguide. That's also why you turn the woofer around, snug it back into the corner. It needs to be close enough to the walls to be within 1/4λ through its range.
At high frequencies, the horn/waveguide sets the pattern. If you use a horn with constant 90˚ horizontal beamwidth, then the high frequency pattern matches the low frequency pattern. You can obtain directivity that is truly constant through the whole audio band, from the Schroeder frequency up. With multisubs smoothing the modal range, you can actually achieve uniformity throuout the room through the entire audio band. It's really awesome.
What I've found works best in the midrange frequencies is to use a moderately sized midrange horn used to fairly low frequency. Think of the midhorn as an interface, between the low frequencies where the woofer is closer than 1/4λ and the high frequencies where the tweeter takes over. The midhorn is designed to be used in the 200Hz and 2kHz decade but its real strength is that it prevents self-interference from occuring. It's just large enough to set the pattern from about 500Hz up if it were used in freespace, but tucked back into the corner, it keeps control all the way down. The mouth is closer than 1/4λ at the low end, and so there is no self-interference. And above that, the midhorn profile sets the pattern, providing a constant 90˚ beamwidth to match that of the tweeter.
How do you guys deal with the room modes when locating speakers at the corners?
I once built 2 big cabinets onto the wall-floor at 2 almost perfact corners in the living room, and I got hhheeeuuuuuuge peaks at 100Hz and 200Hz. Eventually it took -60dB notch filters to make it smooth enough 🙁 Of course that's far from ideal, but I couldn't make it any better. (The speaker cabs were built stupidly solid and secured, I couldn't even dismantle them... They were there until I moved out of that house.)
As to the very wide positioning and large toe-in, I believe it can be done with almost all kinds of speakers. And it's my personal favorite, too. While the speakers don't have to be corner loaded.
I once built 2 big cabinets onto the wall-floor at 2 almost perfact corners in the living room, and I got hhheeeuuuuuuge peaks at 100Hz and 200Hz. Eventually it took -60dB notch filters to make it smooth enough 🙁 Of course that's far from ideal, but I couldn't make it any better. (The speaker cabs were built stupidly solid and secured, I couldn't even dismantle them... They were there until I moved out of that house.)
As to the very wide positioning and large toe-in, I believe it can be done with almost all kinds of speakers. And it's my personal favorite, too. While the speakers don't have to be corner loaded.
- Status
- Not open for further replies.