People tell me, “I hate horn speakers”. Only audiophiles tell me this, of course, but more often than you might think. Ordinary people don’t even know what a horn loaded loudspeaker is, and many of our customers talk about the “cone things” on top of their speakers. Horn hating is an audiophile thing.
Audiophiles have a good half century of training behind this prejudice. When Edgar Villachur and his company Acoustic Research invented the first small direct radiator speaker in the late 1950’s, the AR1, it changed audio forever. From Wikipedia:
“AR’s line of acoustic suspension speakers were extraordinary for their time, as they were the first loudspeakers with flat response, extended bass, wide dispersion, small size, and reasonable cost.”
Just about everything that follows the AR1 in the realm of high end audio for the last 50 years is essentially the same from an engineering standpoint. The AR1 was a little bookshelf speaker, its progeny today might weigh 600 pounds and cost over $200,000, but the concept is the same. Horns were out after the AR1. The magazines in bed with the high end audio industry made sure of that. If you were a serious audiophile, you needed a direct radiator loudspeaker.
I actually don’t have a problem with audiophiles telling me how much they hate the sound of horns, because every single high end company making horn loudspeakers makes them completely differently from OMA. If you look at any other horn, you’ll see the walls are curved. This profile can and usually is of the exponential flare, there are also parabolic, hyperbolic and other flares, and in the exponential category there are sub species such as tractrix, spherical, LeCleach, etc. They are all similar in that their walls have curvature. That may not seem like such a big deal, but it is.
Conical horns are completely different. They have straight sided walls. The sound comes out of the driver at the throat end and sees a perfectly consistent expansion rate, which means the sound wave emerges as a spherical wavefront without any perturbations. That’s not what happens with a curved horn, because the sound wave is now seeing curved walls, a bit like playing pool on a curved billiard table. As the frequency goes up, the sound waves don’t even “see” the horn walls and start to beam, which is why you’ll often see conventional horn speakers toed in to aim at a central listening chair or position- if you’re not sitting there with your head in an imaginary vise you will miss part of the essential high frequency information because its only to be heard on axis. This makes a listening session at a horn afficianado’s home frustrating, because only one person at a time can really hear the music properly.
Conical horns don’t have any of these problems. In fact, one of their attributes is a technical term called “constant directivity” which is one of the absolute most desirable characteristics in the pro audio world. What it really means is that everywhere the horn is aiming (defined by looking at the angles of the horn, and pretending that if it were a fire hose nozzle, who would get soaked sitting in front of it) gets to hear the same thing in the same way.
Many pro horns have been created to have constant directivity through complex throat and mouth geometries, but conicals have this naturally. The other thing they have is a totally natural sound, without colorations typical of other curved horns. This is the real sticking point to my mind, why audiophiles have issues with horn speakers. The problem is the constriction at the throat typical of these horns. Its kind of like the difference between a trumpet and a megaphone. A trumpet is loud, really loud, and its quite short. A megaphone is not so loud, but a voice coming through it is clear. The trumpet is much louder because its more efficient, specifically it couples the air in the mouth of the trumpeter to the surrounding air better than the megaphone, because that constriction presents a small air column which rapidly expands to the sound waves. The conical horn does not have that constriction.
When audiophiles tell me they hate horns, my usual response is, well, you’ve never heard conical horns. If they argue, I simply ask them what company’s conical horn loudspeakers they have heard? Because there are none. OMA is the first company to ever make hifi conical loudspeakers, and there are only a handful of pro companies (actually the best ones) which make conical loudspeakers for use in concerts or venues.
Sometimes audiophiles tell me how much they hated horns after hearing conicals for the first time, such as in our showroom, and its typically offered as a heartfelt confession. “I thought I would hate them, but they don’t sound like horns.”
You may wonder, if conical horns are so great, why is OMA the only company that makes them (for domestic use.) The answer is simple. Size. Conical horns are a lot bigger than their curved cousins. The reason the AR1 was such a huge success, and why it put most horn speaker companies out of business, is size (and cost, which follows from size.) The whole history of audio for the last 50 plus years has been making things smaller and cheaper. Conicals are neither and horns in general have not been on the home audio map since gas was 20 cents a gallon.
Before electronic microphones and amplifiers arrived in the mid 1920’s all recording was done by the musician or singer performing into a big horn. Its the exact reverse of what we do at OMA- the energy coming from the musician’s instrument or singers voice is concentrated by the horn onto a little device which physically cut the groove into a record. The funny thing is that when you look at the historical photos, you only see conical horns, never curved ones (which were used exclusively on the phonographs of the era.) It seems they already knew that the conical horn was the only one which did not color the sound of the performance. They didn’t have the benefit of all our science and technology. They just used their ears.