What are the effects of bi-wiring and bi-amping?

Fundamentally, a loudspeaker crossover varies the impedance seen by the speaker and by the power amplifier. When a full-range audio signal is applied to the terminals of a full-range speaker system, the bass driver(s) will only receive low-frequency signals, the mid-driver will receive mid-band frequency signals, and the tweeter will only get sent high-frequency signals.

This means that if separate speaker cables are connected to the low and high frequency terminals, not only have the drive units had the frequency’s directed and divided for them, but if using a bi-wire setup, the two separate speaker cables will now also carry different signals due to the impedance. So the bass cables carry mostly the low frequencies, and the tweeter cable mostly the highs.

The effects of bi-wiring are subtle, and depending on the cable construction and design, it could be better to go for one better engineered cable than two for bi-wiring. Monitor Audio recommends experimenting with both configurations to find out which one works best in your system. Bi-amping adds an additional amplifier to the system so that the one amplifier drives the low frequencies and the other amplifier drives the high frequencies.

Bi-amping can therefore present a ‘cleaner’ signal at both the low frequency and high frequency speaker terminals, and because the high and low frequencies have already been separated, each has a minimal effect on the other—in essence, the bass has less effect on the delicate treble. In order to best take advantage of bi-amping, the amplifiers should be as independent from each other as possible. For instance, if using two stereo amplifiers, you should use one stereo amplifier for the bass and the other for the treble, minimising the impact of the bass on the treble.