46
Calibration
(cont)
Trim Procedure
Position an SPL meter (average reading, true RMS calibrated VU detector) at the mix position. Set
the SPL meter to C Weighted/Slow. Select the Monitor System to be calibrated. Solo the required
channel/speaker from the Source On section. (MultiMAX won’t allow an invalid selection). Deselect
Mute and Dim. Use the Level/Select control to trim the selected speaker so that the reading on the SPL
meter matches the target SPL indicated on the Calibration Trim Menu.
Note: The target SPL for LFE is approximate only. See the next section for complete instructions on trim-
ming the subwoofer.
Solo the next channel/speaker in the Monitor System to be calibrated and repeat the procedure. Select
another Monitor System to continue the calibration process. When speaker calibration is complete,
press Exit to return to the Setup Menus.
Subwoofer Trim Procedure
The film industry standard sets the LFE reproducing speaker(s) 10dB louder than the center speaker,
measured in the LFE band pass region. To accurately measure this and calibrate the subwoofer(s) you
will need an RTA (real time analyzer).
After calibrating the Main Monitor System center speaker, make sure the noise source is set to Pink
Noise and use the RTA to note the average value of the third-octave bands in the mid-band of the
center speaker. Select LFE and trim the subwoofer level so that the average value of the third-octave
bands between 25Hz and 80Hz is 10dB higher than the noted average value for the mid-band of the
center speaker.
After calibrating the subwoofer, we suggest taking an SPL measurement that you can use as a reference
for subsequent checks and calibration without the necessity of the RTA. The SPL meter reading will be
approximately 4 dB above the target SPL of the center speaker.
If an RTA is not available set the subwoofer to the target SPL indicated on the Trim Menu as an
approximation. Excepting potential standing waves, it should be within ± 1 dB of the correct level.
Subwoofer
Center Speaker
10 dB above Reference
Reference
25Hz
80Hz
2kHz
(Normal)
(Film)
Operation: Setup Menus
