My position has long been that basshorns are too small to support the lowest frequencies unless they are huge things, built-in to the room. After all, bass frequencies are dozens of feet long. You really can't even have a 1/4 wave resonator working at the bottom of the bass range unless it's over ten feet long. So to have a horn be of sufficient length and area to really support the bottom octave requires a structure that is literally as big as a house.

Still, you can make a scaled down version and gain some of its benefits. A truncated horn will work pretty well in many ways, particularly when the room corner is used. But the point is that it isn't realistic to think that a portable basshorn cabinet can support the deepest bass frequencies. Every one I've seen becomes more and more like a quarter wave resonator down low, and then reverts to being a bandpass or direct radiator. That's fine, nothing wrong with that. But it does mean that the lowest frequencies have 10x less power. The response curve isn't flat. What is happening at the bottom frequencies is direct radiation. You can either EQ it back up or limit output to the passband and forget about the range down low.

To me, it was always ironic that some of the most vocal hifi horn proponents - those that dismiss the use of a direct radiating woofer - were often using equalization of their basshorns to increase power for the deepest bass notes. What that really means is that their basshorn system is actually a hybrid, being used both as a direct radiator down low and a horn higher up. There's no problem with that approach, none at all. But that means the talk of "all horns or no horns" is actually just talk because in fact, the basshorn is not fully functioning as a horn.

Still, if what you want is maximum SPL, a horn is the way to go, even a truncated horn. Over the range where efficiency is increased, distortion is decreased. Even if it loses this ability down low, the benefit is gained over the horn's passband and that sometimes makes it worthwhile. As long as you have the real estate, because even a highly truncated basshorn is pretty large.

Those are some of my thoughts. What are yours?

Your right about bass horns operating down low. To get the Lab subs operating at a nearly flat response curve down to 30Hz, Tom Danley says you have to have 6 of them. And even then the mouth area still a little small to support 30Hz wavelengths.

I mean are we talking living rooms or stadiums here? There is a pretty big difference in how one approaches the two problems and trust me they are not the same.

I do a lot of pro sound work, but in all honesty, they don't really care about quality. Its all SPL, flying and trucking. And oh yea, if it also sounds good, thats OK too.

I live for small rooms, currently home theaters, where quality in the sound is what its all about. In that space I prefer NOT to have a horn in a region where it does not provide an advantage. In a small room below about 200 Hz. its not about the kind of enclosure, closed, ported, horn, whatever, its about how many. I recently had dinner with a group of home theater specialists and we all agreed that in the very LF domain its all about numbers - at least four, six is better. I have five. And they don't need to be powerful - hell there's five of them! So LF SPL from a single source in any of my small rooms is irrelavent. So much for large horn enclosures.

Now when we can strt to control directivity and the ear/brain combination starts to tell us where the sources and refections are THEN directivity control becomes everything - it controls the sound quality in small rooms at the mid -> HF.

Keep your LF horns, give me six woofers, three monopoles and three ported.

Reagrding cancellation, look at it as a problem in probability, which is what it really is. What is the prbabilty that I will have five vectors - each sources magnitude and phase - that add up to zero? Its just about nil - doesn't happen. With two sources, it is highly likely to happen at some frequency and with one source it is guaranteed to happen when the source is at a node. But with five sources, it virtually can't happen.

Thats really the point. The five sources will always have a smoother average than any lessor number. Its simple statistics.

• Loudspeakers and Rooms for Multichannel Audio Reproduction - Getting the Bass Right

Please remember that I did my PhD thesis on small room acoustics, and that was more than 20 years ago, so my concepts are based on some pretty substantial theroy. Far more in depth than the simple acoustics theories allow.