Alesis M1Active MKII User Manual - Page 27

Speaker Installation TO SET THE LEVEL WITH A MIXER: 1. Turn on all system components (the M1 Active Mk2s last) and turn the M1 Active Mk2's INPUT LEVEL control all the way down. 2. Play program through the mixer and raise the mixer's fader levels until its meter averages around "0 VU". 3. Raise the Control Room Output to its nominal position (usually "2 o'clock" or 3/4 of the way up). 4. On one speaker, raise its INPUT LEVEL CONTROL for a comfortable level in the engineer's seat (if you have a sound pressure meter, 85 dB SPL is a common standard for listening). 5. Match the level for the other speaker. Note that the numbers on the back panel are only a rough guide; for precise left/right imaging, use pink noise or test tones and a sound pressure meter. The Input Level control has a 28 dB range with a center detent. The detent has no particular meaning, but helps in adding a mental "reference position" when attempting to set levels from in front of the speaker. With the control at a maximum clockwise rotation, 2.0 volt input will produce full amplifier output (102 dB SPL "A" weighted from two speakers at 1 meter). For the technically-minded, here is an approximate chart of SPL levels for various settings of the INPUT LEVEL control, measured at 1 meter from two speakers simultaneously (all settings, especially near the extremes of the range, are subject to a plus or minus 2 dB error): Mark 0 (MIN) 1 2 3 4 5 6 7 8 9 10 (MAX) -10 dBV nominal -- dB SPL -57.0 63.5 68.2 71.0 73.0 78.0 83.5 85.5* 86.5 +4 dBu nominal -- dB SPL -69.0 75.5 80.2 83.0 85.0* 90.0 95.5 97.5 98.5 * denotes recommended setting for control room use M1 Active Mk2 Reference Manual 29