Still with me? Good. It's payoff time. Here's my explanation of what happens in most control rooms. The loudspeakers will emit sound in every direction despite the best efforts of the designer to limit their directivity. Those which pay no attention to directivity issues will also suffer from lumpy off-axis and power response as mentioned earlier. If the side walls of the control room are damped, they will further low pass filter the room reflections. The net effect is to remove, reduce or distort the room reflections that the ear/brain uses to help localize the sound sources (i.e. the loudspeakers and their related phantom images). If there is diffusion in this transmission path, then the reflected energy is robbed of its phase coherence and becomes useless in both the localization process and for the maintenance of timbre, blurring images and timbre. If the reflected energy comes from behind or the same direction as the direct sound, it will not support the localization process as well as laterally reflected energy does. Without sufficient laterally reflected energy, the sound will generally lack a sense of envelopment and, dare I say, musicality. If the decay time of the room is not short and reasonably similar in each octave band from 63 Hz. through 8 kHz., the playback room will impart its own "color" upon the perceived sound.

Us humans are very adaptive. We CAN work in rooms constructed like this. BUT, we struggle, and have these ongoing debates about rooms and loudspeakers. One guy loves this room and hates that loudspeaker. Another guy hates this room and loves that loudspeaker. Whatever. We all manage to adapt to a particular playback system in a particular room. Once we have learned "the sound" of "our particular" system, and have learned to produce predictable recordings with that setup, other sounds often seem unnatural and the readjustment process can be time consuming and unpleasant. (This is exactly how the NS10s-on-the-meter-bridge phenomenon works, and this is why some engineers end up mixing to pain cues.)

Now, here's what happens in The Plant's new mix room, "The Garden," with the weird-looking loudspeakers. These monitors emit sound in every direction like any other speakers, to be sure. However, there is NO low pass filtering of their output in the horizontal plane until we are over 90° off axis. The directivity is reduced in the vertical plane only. The reflective and non-diffusive side walls of the room provide full-spectrum lateral reflections that aid in the localization process. The rear wall is absorbent at low frequencies and spectrally reflective at higher frequencies by use of a large cylindrical reflector that directs energy back toward the side walls of the room. The front wall is a very efficient broadband absorber. The room has a constant decay time of less than .2 sec from 250 Hz all the way to 8 kHz. It doesn't sound the least bit overdamped. Normal speech in the room sounds normally ambient. With the ultra-wide dispersion monitors, the sweet spot is ridiculously huge. The key word to describe how all this sounds with music playback is clarity. It's almost like not listening to speakers at all (indeed, in some controlled double-blind listening tests of these ultra-wide designs using professional listeners, one listener stopped the test, allowing that she got confused and thought she was listening to a live player, for an unprecedented first time in her testing experience!). Everything in the recording is utterly revealed, but without sounding analytical. As a matter of fact, playback sounds extremely musical and entertaining - and very "clear." Those are not adjectives that are usually used to describe a single playback system, but they describe The Garden and its monitors well.

"How do mixes travel?" you may ask. In fact, speakers of similar design have been in daily use at a small post-production/mastering facility in New England for several years now and the answer has consistently been, "Very well, thank you." Experienced engineers that hear the room immediately recognize that, however different all this looks, the mixes made with these ultra-wide dispersion speakers will travel to other environments extremely well, without significant problems, and that has proved to be the case.

Please keep in mind that none of the stuff I've described here negates most basic criteria for good room and speaker design. However, one of my pet peeves is that many people regard listening room acoustics as an exercise in damping or diffusing reflections. This is a questionable practice in general. Properly managed, full-spectrum reflections provide "good data" for our auditory system to use in processing the information provided by the recording.

In conclusion, I need to stress that the ideas that I've put forth here are not all that new, nor are they necessarily all my own. My partner David Moulton, for instance, has developed a very simple, very effective low-cost control room topology suitable for all types of speakers using this reasoning. There are plenty of people who recognize that wide dispersion loudspeakers and rooms like the one I've described here are an excellent approach to room design. What is unique and special here, and of importance to the professional audio community, is that these ultra-wide dispersion loudspeakers are now installed in a world-class room that can take full advantage of them, and this is in one of the foremost mainstream pop/rock recording studios in the world. In an industry filled with lemmings, this is no small achievement. One thing is for sure, though. So far the voting is unanimous - it sure "sounds good!"

Manny LaCarrubba is the president of Sausalito Audio Works. He wishes to thank his partner David Moulton, from whom he appropriated much of the information for this article.