ELAC SUB 2090 Operating Instructions Manual page 28

Conventional HiFi systems
Standard connection (stereo RCA)
This is the standard connection variant used in conjunction with a stereo (pre-) amplifier.
If you want to connect the subwoofer to the output from a stereo amplifier, make sure that the outputs to the main loud-
speakers are still carrying signals. This is the case for most PRE-OUT sockets.
The "CUTOFF FREQUENCY" must be adjusted to suit the main loudspeakers.
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