How do Tectonic loudspeakers throw farther than other speaker systems?

The wide directivity and diffuse characteristics provide slightly better “drop-off” performance in enclosed rooms than with traditional loudspeakers.

For all speakers that provide room sound there is a measurement called the Critical Distance. This is the point where the level of direct sound equals the level of the reverberant sound in the room.

The more directional a speaker is, the further away from the speaker the Critical Distance occurs. The Critical Distance changes from about 30” (75cm) for an omnidirectional source to over 6.6’ (2m) for a more directional one.

Traditional sound reinforcement speakers have always tried to avoid sending too much energy off to the sides, top and/or bottom of a venue because the waves from these speakers are phase coherent and they can create unwanted reflections bouncing off the walls, floor etc., which obscures intelligibility.

Focusing coverage increases the Critical Distance, meaning that more of the audience is in a region where the sound falls with the square of distance. Putting the audience in such a region means that those at the front will experience significantly higher sound levels than those at the rear – this is not ideal.

Line arrays and steerable column loudspeaker systems, by design direct the audio energy only at the audience, as much as possible. The way that these systems increase throw is by increasing the relative volume of the speaker elements that are aimed at the farthest locations, e.g. the top boxes in a line array are receiving more relative power than the boxes located in the lower part of the “J” array.  This allows similar sound levels reach the front and back audiences.

This is the opposite of how real instruments radiate sound into a room, so the effect is not natural.

Enter the DML

DMLs have wide directivity and therefore give a much reduced Critical Distance. This means that after the first 3’ (1m) or so, the drop-off in level is closer to a linear slope. Basically the balance between the direct and reverberant fields is much smoother with an omni-directional source such as a DML.

In other words, as you walk away from a DML you are already almost certainly in the reverberant field (after the first 3’/1m or so) and so will experience a much slower drop off. The initial region (direct sound field) is less intense because the DML is radiating its sound over a wide angle, not ‘firing’ it in a specific direction like a traditional system.

The near omni-directional nature of DMLs would cause significant intelligibility problems if it wasn’t for the fact that DMLs are predominantly diffuse sources. This means that all the energy going into driving the reverberant field is not bouncing around and causing interference. It’s actually doing what the sound from real instruments does.