MartinLogan Source Speakers user manual Dispersion Interactions, Controlled Horizontal Dispersion

DISPERSION INTERACTIONS

Controlled Horizontal Dispersion

Your Source’s launch a 30 degree horizontal dispersion pat- tern. This horizontal dispersion field gives a choice of good seats for the performance while minimizing interactions with side walls (see figure 7). Make sure both speakers stand exactly at the same vertical angle, otherwise the image can be skewed or poorly defined. The wave launch of both speakers is extremely accurate in both the time and spectral domain. Consequently, small refined adjustments can result in noticeable sonic improvements.

Controlled Vertical Dispersion

As you can see from the illustrations, your Source speak- ers project a controlled dispersion pattern (see figure 8). Each Source is a 28 inch line source beginning 22 inches above the base. This vertical dispersion profile minimizes interactions with the floor and the ceiling.

Figure 7– 8. As can be seen here, point source concepts invite a great deal of room interaction. While delivering good frequency response to a large listening audience, imag- ing is consequently confused and blurred.

Figure 9–10.Even though they suffer from “venetian blind” effect, angled multiple panel speakers can deliver good imaging, but only to specific spots in the listening area.

Figure 11–12.A controlled 30 degree cylin- drical wave-front, a MartinLogan exclusive, offers optimal sound distribution with minimal room interaction. The result is solid imaging with a wide listening area.

Three Major Types of Dispersion

It is a known fact that as the sound wave becomes pro- gressively smaller than the transducer producing it, the dispersion of that wave becomes more and more narrow, or directional. This fact occurs as long as the transducer is a flat surface. Large flat panel speakers exhibit venetian blind effects due to this phenomenon. This is one reason why many manufacturers opt for small drivers (i.e. tweeters and midrange) to approximate what is known as a point source wave launch.

Historically, most attempts to achieve smooth dispersion from large flat panel transducers resulted in trade-offs. After exhaustive testing of many different methods, we conceived an elegantly simple, yet intensely hand craft- ed process. By curving the radiating surface, we create the effect of a horizontal arc. This allows the engineers at MartinLogan to control the high frequency dispersion pat- tern of our transducers.

12 Dispersion Interactions