Hook 'em Horns! Juneau AK

You've probably noticed at recent CES and CEDIA trade shows that a number of horn-loaded speakers are popping up. It may come as a surprise, too, because horns are typically considered (at least in the U.S.) to be fodder for Lo-Fi professional applications where the primary goal is volume and lots of it. Unfortunately, that stereotype has led many people to overlook horns as a legitimate and beneficial element of speaker design.

To a certain degree, horns deserve their bad reputation. Back in the middle of the last century, horns were used to increase the output capability of sound systems at a time when amplifier power was limited. Those horns also happened to sound pretty bad, but not because the theory was bad. They were simply bad horns. These days, horns are much improved, thanks to significant technological advancements in the last 50 years.

Now that horns are suddenly all the rage, you should know some of the benefits that they provide. First, obviously, is higher sensitivity and increased output through the processes of compression and impedance matching. The horn acts as an impedance transformer, improving energy transfer between the two drivers diaphragm and the air molecules. Given the same amount of power, a horn-loaded speaker will therefore play louder than a similar speaker without horns. Since todays power amplifiers are titans compared with their ancestors, horns may no longer appear to be required for adequate output levels in many applications. Im sure, for example, that you can find a plethora of non-horn-loaded speakers that play plenty loud in your living room. However, for larger home theaters, like 30-feet by 20-feet rooms, you will find that high-output designs become necessary if you want to reproduce all of the impact of action films. You need speakers with sensitivity ratings in excess of 94dB, and a horn-loaded design is definitely the easiest way to get there.

Second, horns shape the dispersion pattern of a speaker. They capture all of the sound energy produced by the transducers and aim itas opposed to letting it randomly propagate out according to the inherent dispersion character of the individual transducers.

Most of the time you want a speaker to cover the entire audience but not spray the whole room with stray sound energy. Its virtually impossible to accomplish this without a horn or waveguide of some kind to focus the speakers dispersion. Transducers in a bafflecalled a speaker cabinetwant to radiate most frequencies in a spherical (bass) or hemispherical (mids and highs) pattern. Unless the audience is on both the ceiling and the floor, 180-degree horizontal and vertical dispersion is a bit too broad.

Interestingly, horns do not always narrow the dispersion of a speaker. For example, a two-inch tweeter will produce an extremely narrow beam of sound at very high frequencies compared with a three-quarter inch tweeter.

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