In the operation is still a lot of these "dinosaurs" of the mid 90s. A characteristic feature of built-in amplifiers such devices - they are designed for load 2 ohms and have a good supply of power. This is due to the fact that in the middle position fader front and surround speakers are connected in parallel. However, to use them in conjunction with acoustic component is impossible. The reason is simple - the introduction of the fader increases the output impedance of the amplifier, which leads to a change in crossover. Therefore, the only option enhancers such devices with modern acoustics - dual channel configuration, with the fader excluded from work.
In this version, you can add a subwoofer to include it in a "mixed-mono". Since the relationship between the levels regulate front speaker and subwoofer impossible, depending on the sensitivity applied to select one of the heads of connectivity options.
Option A is used in the case where the sensitivity of the front speakers 3-5 dB higher than that of the subwoofer. In this embodiment, they are connected to the amplifiers are not bridged, and the usual way, and the power supplied to them is not more than 7 w / 4 ohms. To obtain sufficient volume of the front acoustic desirable to use high-sensitivity head about 91-93 dB. Pay attention to their phasing - one of the "poluusiliteley" inverting the second - non-inverting. HPF cut formed by the capacitors C1 and C2 can be chosen arbitrarily, but the presence of capacitors is crucial - they do not miss out on the dynamics of the DC component from the output amplifiers. Front head shown conventionally broadband, but they may be coaxial or component.
Option B is used in nearly all heads of sensitivity. The presence of capacitors C1, C2 for the normal functioning is not necessarily because it is used in a bridge connection. In the absence of capacitors in the passband head subwoofer filter work in parallel. This reduces the load impedance to 2 ohms, but the amplifier is designed. Subwoofer in both cases the second-order filter (C3L1R1).
