Wayne Parham
Active Member
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 achieve 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 achieve constant coverage of the entire audio band throughout the room this way.