In my last post about the sweet spot, I explained how critical it is for the sound from the front left and right channels to arrive at your listening position at the same time. Without equal arrival time of the direct spectral energy from the recording, ahead of the reflected sounds, the stereo image collapses, the pin-point localization of instruments and voices is lost. That’s because a law of nature called the “precedence effect” causes us to hear the speaker we are sitting closest too first and most loudly, its not the fault of the equipment that the image is lost. In nature, this was a survival skill, to better hear danger when it arose and know how close it was instinctively, usually running the opposite direction.
Since the beginning of the stereo era, a balance control has been a standard feature included in all integrated amps, pre-amps, and receivers. Why? Because rooms are not always symmetrical and the furniture placement dictates the position of the speaker system in many homes, it is not always possible to arrange for the listening position to be centered exactly between the two main channels. The purpose of the balance control is to equalize the output levels at your listening position even when its not centered between the two main channels.
Many audiophiles today use desk-top systems because they are downloading HD music files to their computer, a perfect scenario for hearing great stereo imaging from even low quality speakers. Sitting close, the listener hears more of the speaker and less of the room, we call that “near field listening”. In this scenario, the balance control is unnecessary, it can remain in the 12 o’clock position because the listener is getting equal levels by virtue of his own location.
In the living room, you sit much further away from the speakers and are not always centered between them. Use your balance control to correct the offset, you 
will restore the stereo image dramatically.
Essence™ Electrostats focus their output to the listening position, delivering higher levels of the direct sounds we hear to detect the stereo image. This ability is unique among the speakers out there today, most conventional speakers actually lose half their output on the way to the listeners ears, allowing more reflected sounds to dominate and distort the stereo image by its interference.
As I researched the forums for discussions about the balance control, it was obvious that very few people know why it exists or what it’s meant to do. That prompted me to offer this short blog on how and why to use your balance control. Happy Listening!
Bob Rapoport
Hi Sam, its my pleasure to remind people what the sweet spot is and how to overcome asymmetrical listening positions. Back in the day, channel balance was not something anybody could take for granted with vinyl records, phono pre-preamps, and cartridges. Things got better along the way but nothing can overcome an imbalance in the arrival times at your ears better than a good old fashioned balance control. 🙂
Bob
sam
Thanks for this article. The information makes me a little less neurotic about having furniture right in the sweet spot. The balance control does restore the stereo image for a listening position that is off center.