SPL 2Control 2860, Manual

Page: 17 / 24

2 Control 17
Control Elements
The high-grade potentiometer regulates the audio signal directly to
avoid any coloration/distortion typical of VCAs, DCAs, etc., which re-
quire higher inter-channel tolerances and tend toward higher distortion
figures. Moreover, this potentiometer possesses an optimal rotational
torque and “feel” for precise hand control.
Calibration of the Monitoring System
Both the signal level which is send to the 2 Control as well as the input
sensitivity of the power amps or active speakers should be matched to
ensure a proper overall gain. An inappropriate adjustment might occur
when, for example, a fairly small volume level setting at the
2 Control
might already result in an extremely high playback level.
Important: You can encounter very loud signals during calibration,
so be sure to keep your ear protection on.
For calibration we recom-
mend measurement with a SPL Meter (in this case, SPL means “Sound
Pressure Level“). Place the measuring microphone on the listening po-
sition run pink noise from a generator calibrated to 0 dBu.
Each measurement should be done through one channel and loud-
speaker at a time. A recommendable calibration is the playback of a
83 dB SPL reference signal at the playback location—a common refer-
ence volume level. The DAW output level should be adjusted to 0 dB, and
next, the power amp‘s or active speaker‘s input level should also be set
to 0 dB. Now the
2 Control level control is adjusted until the SPL Meter
measures 83 dB with the pink noise playback. For a perfectly matched
gaining the VOLUME control would now be set above a 12 o’clock scale
position. At this point one can record or note the exact value for 83 dB.
Should this 83 dB SPL occur markedly above a 60-80% scale position,
one should lower the power amp’s/active speaker’s input sensitivity.
On the other hand, the power amp’s/active speaker’s input sensitivity
should be raised if the 83 dB SPL point is reached far before the 60%
control level. In cases where regulating power amp/active speaker in-
puts is not enough, one may achieve optimal values by changing the
D/A converter output level (for example from +4 dBu to 0 dBu or -10 dBV
in cases where this switch option may exist). In any case, the convert-
ers should always be driven at full scale from the DAW.
Please also note that you can adjust sensitivity of IN 2 for other sources
(refer to „Input Sensitivity IN2“ on page 13).