Bi-Wiring
How it Works
Bi-wiring is accomplished via separate pairs of terminals on the loudspeaker. In the case of the GX Series, the bottom terminals connect to the bass driver(s) and the top terminals connect to the tweeter in 2 way loudspeakers, or the mid and tweeter in 3 way loudspeakers. The normal function of a loudspeaker crossover is to guide appropriate frequencies to the appropriate driver/tweeter. Low frequencies to the bass drivers, mid frequencies to the mid/bass drivers and high frequencies to the tweeter.
Fundamentally a loudspeaker crossover varies the impedance seen by the speaker and by the power amplifier. The situation is such that when the full range musical signal is applied to the terminals of a full-range speaker system, the bass driver(s) only receives low frequency signals, the mid driver receives the mid band frequency signals and the tweeter only gets sent high frequency signals. This means that if separate speaker cables are connected to the low frequency terminals, and the high frequency terminals, not only have the drive units and the frequency’s directed and divided for them, but the two separate speaker cables will now also carry different signals, the bass cable mostly the lows, and the tweeter cable mostly the highs.
Once the high and low frequencies have been separated in this fashion, the strong current pulses and surges demanded by bass drivers when reproducing bass or drums, will not interact with the delicate sounds of a flute or cymbal.
The Effects
In a single wired system, unwanted mechanical and electrical resonances manifest as distortion at both sets of speaker terminals. Due to the impedance of the speaker cables, these distortions will not be entirely cancelled by the amplifier. Instead, they modulate between the two crossovers, and degrade sound quality. When bi-wiring, this interaction is minimised as signal distortion is ‘seen’ at the amplifier’s output where it can be more effectively cancelled. Bi-wiring therefore presents 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 does not overpower delicate treble.
In terms of the audible benefit, bi-wiring, provides more clarity and detail to the midrange and high frequencies. Often the bass will become faster and tighter. Focus and staging will improve as well. In all, this is a very effective and desirable improvement and is highly recommended by Monitor Audio.
WARNING: When bi-wiring always remove the cable jumpers between the terminals before connecting any cables.
Port bungs
WARNING: Care must be taken not to insert the port bungs too far into the port, as this may result in the foam bung being lost inside the cabinet.
If the loudspeaker is to be installed in a small room, typically 9 sqM ( 80 sqFT), or a room known to reproduce accentuated bass response, it may be desirable to fit port bungs. However, experimentation is recommended with positioning of the loudspeaker in the room prior to fitting. To optimise performance from the loudspeaker it is important to ensure the loudspeaker is not positioned too close to a wall or near the corners of a room (refer to the suggestions on pages 8 and 10).
If the positioning of the loudspeaker is predetermined by room aesthetics or layout, or you find you have accentuated bass, please move on and read point 1 for the GX50/ GX100 and point 2 for the GX200/ GX300.
1.Where bookshelf/ stand-mount speakers (GX50 & GX100) are to be sited in close proximity (less than 8 inches/ 20cm) to a rear wall (such as on a bookshelf, positioned in a cabinet or on a stand sloce to a wall), we recommend fitting port bungs to the ports. This will reduce the bass ‘boom’ sometimes termed as overhang, and assist the loudspeakers to reproduce their best performance under these environmental conditions. ‘Boom’ is generally caused when bass energy from the loudspeaker ‘excites’ room modes and causes an accentuation at a particular frequency, or number of frequencies.
2.Where floor-standing loudspeakers (GX200 & GX300) are to be sited in close proximity (closer than 18 inches/ 45cm) to a rear wall, we recommend fitting the port bungs. This will reduce the bass ‘boom’ sometimes termed as overhang and assist the loudspeakers to reproduce their best performance under these environmental conditions. This is caused when bass energy from the loudspeaker ‘excites’ room modes and causes an accentuation at a particular frequency, or number of frequencies.
When fitting port bungs the overall bass extension will not be reduced, however bass energy/ output around the port tuning frequency will be reduced. This has the effect of reducing bass ‘boom’ while increasing bass clarity and apparent agility.
Experimentation is highly recommended.
