Three Major Types Of Dispersion - MartinLogan i User Manual

Three Major Types of Dispersion

In the field of loudspeaker design, it is a known fact that as
the sound wave becomes progressively 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 why most manufacturers opt for
small drivers (i.e. tweeters and midrange) to approximate
what is known as a point source wave launch.
Figure 18–19. 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, imaging is consequently
confused and blurred.
Figure 20–21. 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 22–23. A controlled 30-degree cylindri-
cal wave-front, a MartinLogan exclusive, offers
optimal sound distribution with minimal room
interaction. The result is solid imaging with a
wide listening area.
12 Dispersion Interactions
Historically, most attempts to achieve smooth dispersion
from large flat panel transducers resulted in trade-offs. After
exhaustive testing of these different solution attempts, we
found an elegantly simple, yet difficult to execute solution.
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 pattern of our transduc-
ers. That is why you see the gentle curve on our products.