What is SDA® Surround Sound Technology?
SDA stands for Stereo Dimensional Array, a patented Polk Audio exclusive*. Matthew Polk describes SDA Surround Technology as "a mixture of acoustical engineering, psychoacoustic principles and a little magic."
To understand how SDA Surround Technology creates 360 degree surround sound,
we must understand how sound works and how you perceive sound. Sound travels
through air from the source to your ears at a fairly high speed, much like waves
travels through water.
Our ears are positioned at the sides of our head so we can distinguish exactly what direction a sound is coming from. The tiny difference in intensity and arrival time from one ear to the other allows us to sense immediately from which direction sound is coming. The ear closest to the source of sound hears the sound louder and slightly before the other ear.
Now that we know how sound travels through the air, we need to know how a recording
is made to be played over an audio system. When a multi-channel recording is made,
sound supposed to be heard at your left ear comes only out of the left speaker.
However over a sound system, you hear sound from the left speaker not only in
your left ear but also your right ear as well. The dedicated SDA driver produces
a SDA signal to control the amount and type of sound the further ear hears. By
carefully controlling the SDA signal, SDA Surround Technology allows the sound
image to be precisely steered and projected into the room. You'll experience
sound effects and instruments coming from all around you, with no physical
speakers beside or behind!
This is why most conventional "front only" speaker systems don't have much of an aural image beyond the physical boundaries of the speakers. By understanding how we perceive sound allows us to project the sound image well beyond these boundaries of the speaker bar. This gives SurroundBar its magic while achieving the surround effect independent of room boundaries.
What SurroundBar gives you is an easy to set up, awesome sounding surround system that blends into the room.
Read Matt Polk's SDA Whitepaper for an even more in depth explanation on SDA Surround Technology
* US Patent # 6937737