Pars, I don't know if your VR4s are engineered the same as my VSA Endeavor SEs, so perhaps I shouldn't be answering you. But here's what my speakers' owners' manual says:
SPEAKER TERMINATION
The Endeavor SE is a three-way speaker system. An ideal scenario is to use a very high quality, medium power amplifier to drive the Endeavor SE for maximum sonic performance. We have had great results using amplifiers with 50-watts up to 300-watts per channel, both tube and solid state. Bi-amping (using two amplifiers to power each channel independently or two amplifiers to power the upper and lower frequencies independently) is supported with our bi-wire inputs.
High Frequency Input
The pair of WBT binding posts on the top of the backplate are connected to the passive internal crossovers that drive the midrange/tweeter module which includes the crossover and midrange, front tweeter and rear ambient drivers. You can use either small spade lugs or banana plugs to connect your main amplifier.
Low Frequency Input
This pair of WBT binding posts on the bottom of the backplate plate connect your main amplifier to the woofer module which includes the crossover and pair of woofer drivers.
Jumper Usage
Jumpers are NOT provided with this system. The ones available as plates tend to degrade the sonic signature dramatically and are not advised. If you are not bi-wiring, please seek out a set of quality copper wire jumpers, bring your signal into the upper pair of binding posts and “jump down" to the lower pair.
However, the Endeavor SE is designed to for Bi-Wiring to achieve the greatest spatial quality and optimal performance. If you have not invested in a high quality bi-wire speaker cable, please consider doing so for best performance. Your dealer should be able to provide you with a sample pair to evaluate in your system.
Explanation and Benefits of Bi-Wiring
This cable setup involves using two separate pairs of speaker cables or a bi-wire speaker cable to deliver the signal to the woofer and midrange/tweeter modules which results in superior image depth, cleaner upper midrange/treble, and a larger sound stage. These benefits are due to the isolation of the powerful bass signals from the more delicate treble frequencies as the signal travels up the speaker cables. Since there is generally ten times more voltage present in the bass signal, the generation of a magnetic field in the positive and negative conductors will interfere with the more delicate treble signals. This magnetic modulation is easy to hear on a high resolution speaker like the Endeavor SE but may not be as audible on low-resolution speakers. Using two separate conduction paths will enable the bass frequencies to be separated from the treble frequencies due to the high impedance “seen” by the signals due to the internal crossover networks. In other words, since there is a “high impedance” (to low frequencies) in the midrange/tweeter crossover, bass frequencies WILL NOT travel from the amplifier up to the midrange/tweeter unit, even though both speaker cables are connected to the same binding posts on the amplifier. The opposite effect occurs in the woofer cables, where no midrange/tweeter frequencies will travel due to the high impedance “seen” as the result of the woofer crossover. Crossover filters work due to the reactances supplied by the inductors and capacitors; inductors generate a “high impedance” to midrange/treble frequencies and capacitors generate a high impedance to bass frequencies -- it’s like pouring water on the side of a hill: the water will never travel uphill against gravity.
I started out (my first day with the speakers) using high-quality large-gauge jumpers, but, as I had a spare pair of speaker cables in a closet, tried bi-wiring - simply running two pairs of cables from my amp's outputs and connecting one to the HF inputs and one to the LF posts. I was shocked by how much better it sounded. I expected any difference to be minimal, but I was blown away by the improvement.
