Carvin FX3244 Instruction Manual - Page 35

FX44 Mixer Bi-Amping and Tri-Ampinq Section 6 BI-AMPING & TRI-AMPING 1) DIFFERENCES BETWEEN CONVENTIONAL "PASSIVE" AND BI-AMPED / TRI-AMPED SOUND SYSTEMS We have discussed how to set up a conventional sound system where a full range audio signal is sent to one amplifier. The amplified signal is then fed to a high level crossover within the speaker. This crossover will separate the 'lows' from the 'highs' and send the respective signals to the low and high frequency drivers. In 'Bi-Amping', the system utilizes a low level or 'active' crossover. The active crossover receives the output signal directly from the pre-amp outputs of your mixing console. Internally, the active crossover divides the signal into its high and low frequency signals. The low frequency signals are then fed to the amplifier that directly sends to only the low frequency drivers (woofers). The high frequency output of the active crossover similarly feeds the amplifier dedicated to the high frequency, which in turn feeds only the high frequency drivers (horns). Bi-amplification requires the use of two power amplifiers, one dedicated to high frequency drivers and another for the low frequency drivers. Bi-amplification will deliver a cleaner sound with minimal distortion and will drive the loudspeakers more efficiently. Bi-Amping will offer better control over the crossover points (The point where if a signal is higher it is sent to the high frequency, if lower then sent to the low frequency.) as well as the relative volume levels of the high and low frequency components. Tri-Amping is the same as Bi-Amping except it adds in a midrange output , thus making a threeway system. In Tri-Amping, the output of the mixing console (full range audio signal) is fed to an active crossover that splits the audio signal into three frequency ranges: high, midrange, and low. The crossover outputs are fed to their respective amplifiers, subsequently driving the high, mid, and low frequency range drivers. Tri-Amping offers exceptional control over the relative levels of each element's volume while offering selectivity for each of the two crossover points. Tri-Amping is often used in high-quality high-level sound reinforcement applications. 2) BENEFITS OF BI-AMPING AND TRI-AMPING Bil"Tri-Amping provides a great degree of efficiency that is typically lost by a conventional 'passive' crossover. Conventional crossovers use inductors, resistors, and capacitors in their design. These electronic devices can affect the output response of the power amplifier or waste much of its available output power. Since Bi-Amping or Tri-Amping bypasses in speaker crossovers a more efficient delivery of power from the amps to the speakers is achieved. This results in greater efficiency from the sound system. The components of a passive crossover are used 'In line' with the outputs of the power amplifier and they affect the way in which the amplifier responds. This interaction can reduce the 'Damping' of the amplifier. Bi-Amping bypasses the passive crossover and offers a more direct output from the amplifier, effectively improving the damping performance of the system. Bi-Amping & Tn-Amping also provides real power output 'Headroom' advantages. High frequencies tend to 'Ride' on top of the higher energy of amplified low frequencies. As an amplifier begins reaching its full output power capacity, the high frequencies may reach the maximum output capabilities, of the amplifier, before the low frequencies do. This effectively clips the high frequency material reducing its clarity. Since the human ear is very sensitive to high frequency distortion, this type of 'high frequency' clipping is very noticeable. By separating the high and low frequency signal prior to amplification, by the systems power amplifiers this, headroom problem is minimized. Bi-Amping allows for more low frequency headroom and far greater high frequency headroom (when compared to passive systems), and offers increased volume with less overall distortion. 6-1