Channel power (@2-ohms)
Rated power output by the amplifier per channel when a load (speakers) is connected to it with a nominal impedance of 2 ohms. For details, see "Nom. channel power (at 1 Ohm)”.
Bridge connection
Rated power delivered by the amplifier to a load connected in a bridge circuit. For more information about the rated power, see "Nom. channel power (at 1 Ohm)”.
With a bridged connection, the speaker is connected not to one channel, but to two at the same time — the “positive” connector of one channel and the “negative” connector of the other are used. If the amplifier has a similar format of operation, then such a pair of channels operates in antiphase, due to which the power is summed up. This allows you to connect speakers to the amplifier, the power of which is twice the nominal power of the device: for example, at 150 watts per channel, 300 watts of acoustics can be bridged. If there are 4 or more channels, it becomes possible to use several speakers according to the "bridge" scheme. This is usually directly indicated in the specifications — for example, the entry "2x300 W" in the "Bridge connection" item means the ability to work with two speakers, each with 300 W.
The requirements for load resistance when connecting with a bridge are the same as for conventional; see "Maximum Resistance" for details.
Signal-to-noise ratio
One of the main parameters that determine the sound quality of the amplifier as a whole: it describes the ratio of the useful signal (in other words, “clean” sound) and various extraneous noises. This takes into account almost all noise — both due to external causes (for example, electrical "pickup"), and created by the device itself (for example, due to heating during operation). Accordingly, the higher the signal-to-noise ratio, the less audibility of various interferences and the clearer the sound is obtained (of course, under normal operating parameters). The average for car audio is 95-100 dB, but in advanced models this value
can be significantly higher.
At the same time, this parameter is not critical for monoblocks designed for subwoofers — most of the interference is high-frequency and will simply not be heard on the low-frequency speaker. The sound quality in this case is highly dependent on the characteristics of the speaker (much more than in multi-channel models), and is weakly related to the “noiselessness” of the amplifier.
