The two sets of binding posts, on the rear of your speakers, enable the Bi-Amplfication of your speakers. While certainly not necessary to the complete enjoyment of your Polk speakers, it can be a way of upgrading the relationship between what is powering the speakers and the speakers themselves.
Bi-Amplifying your speakers would involve removing the binding post jumper plates that link the upper and lower pairs of binding posts. Now you can think of your speakers as two separate sections no longer joined together by the jumper plates. In most Polk speakers the upper binding posts connect to the high pass filter section of the internal crossover and the tweeter. In some Polk speakers the upper set of binding posts connect to the mid range section of the internal crossover and the tweeter and mid range drivers of the speakers. The lower binding posts connect to the balance of the speakers’ components, usually the mid range and woofer, but with some speakers just the woofers.
It's possible that your multi-channel receiver may have the capability of utilizing four of the available amplification channels to independently power the upper and lower set of binding posts. If so, this should be covered in the receiver’s owner’s manual and would involve running an additional pair of speaker wires alongside the original wires to link the “new” amplifiers to these additional connection posts.
You might ask, “What is this going to do for the sound?" In general terms, audio enthusiasts find that Bi-Amping improves the way the sound system handles those more demanding moments when listening to music or watching cinema. Think of “four wheel drive” when it applies to a car or truck going over rough terrain. Since the task is harder, it is advantageous to have the engine’s power go independently to each of the wheels. The same can happen in audio reproduction, when the piece of music is at its most demanding it can be helpful if each section of your speaker had its own source of energy. The feeling will be that the sound being produced is more effortless, less constrained.
For owners of separate audio components, control preamps and power amps, having the ability to Bi-Amp your Polk speakers offers the owner the choice of selecting a power amplifier based on the character of its sound and less on the amount of power it produces. If, for example, a particular amplifier manufacturer makes a model that sounds especially wonderful in the treble (higher) range, but might not have enough overall power for high volume-level demands, allow that amp to be the amp that powers the tweeter in your speakers, freeing you up to choose a more powerful model to power the bass and mid range sections of your speakers for bigger overall volume. (Keep in mind, the two amplifiers would need to have the same input sensitivities, or at least one of them would need to have a level adjustment capability, to maintain the original tonal balance of the speakers.)
This article was last modified May 18, 2013