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Sound module USM-RC-2
22
BEIER-Electronic
03.02.2014
Loudspeaker
You can connect every loudspeaker to the sound module USM-RC-2, which has an
impedance of at least 4
Ω
and is designed for the respective maximal power. We
recommend using full range loudspeakers with 4 or 8
Ω
. Higher impedances are also
possible, but the volume decreases with higher impedances.
The maximum power and thus the volume of the sound module, is also heavily
dependent on the height of the supply voltage.
The following table shows which maximum sine-wave power per loudspeaker at
different voltages and loudspeaker impedances can be reached.
U=6V
U=7,2V
U=8,4V
U=9,6V
U=12V
Power at 4
Ω
4,5W 6,5W 8,8W 11,5W 18,0W
Power at 8
Ω
2,2W
3,2W 4,4W 5,8W 9,0W
Power at 16
Ω
1,1W
1,6W 2,2W 2,9W 4,5W
These performance levels refer to a full scaled sine wave, but not to an overdriven
sine wave. In practice, it is possible to overdrive the amplifier in somewhat whitout
decreasing noticeable the quality of the sound playback of the module. So it is
possible to reach a higher power output with low voltages (e.g. 7,2V) than listed in
the table above.
However, as there is a double amplifier on the sound module you have the choice of
of connecting 1 or 2 loudspeakers. Using 2 loudspeakers, the output power has
doubled. But doubling the output power doesn’t mean the volume has doubled,
because the volume perceived by the human ear is unlinear. For doubling the
volume, you need about the 4 to10-fold power.
To reach a perfect level of volume and sound quality, you have to install the
loudspeaker in a suitable resonant body (loudspeaker box). A loudspeaker, which lies
only on the table, doesn’t reach optimum sound quality.
At every amplifier heat arises through power dissipation. This heat must be
dissipated by a cooling element into the air. Please pay always attention to a good air
circulation to prevent overheating. Especially at higher voltages (e.g. above 9,6V)
and 2 connected 4 Ohm loudspeakers, it is perhaps neccessary to use active cooling
of the sound module, with a little fan.
