L-Acoustics V-DOSC, Руководство оператора

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L-ACOUSTICS V-DOSC Manual Version 4 6/29/2005 Page 128 of 158
♦
Change the polarity of the subs back to the normal values and confirm that maximum summation
is obtained
4W, INFRA or X presets: subs = +ve polarity
X AUX preset: subs = -ve polarity
♦
Apply the same delay to FOH R subs (or FOH L if measurements carried out on FOH R)
Note: Alternatively, if a time domain measurement system is available, follow the guidelines outlined in
Section 1.15 to time align the “sine wave signature” of the sub and low channel impulse responses.
7) Check the overall tonal balance of one side. Select the desired preset (LO or HI shelving eq) and
perform band attenuation using DSP output gains to achieve the desired tonal balance.
Note: For larger arrays (12-16 enclosures), mid and high output gains can be increased by 3-6 dB to
compensate for increased low end coupling. Simple attenuation is generally all that is necessary – do
not reach for the graphic equalizer first! Keep in mind that the best frequency response is not
necessarily a flat line from 20 to 20k Hz (see the above discussion on tonal balance).
8) Duplicate settings for the other side and verify that both sides are the same by measuring the Left
and Right frequency responses at the mix position.
9) Measure FOH Left (or Right) frequency response at a number of representative locations
throughout the coverage region (9-12 measurement locations). Store the results and perform a
spatial average. Note: Be careful of wind effects and make sure that the measured HF response
above 8 kHz is stable and repeatable.
10) Compare all measurements to see if there is good correspondence (i.e., system coverage is
acceptable) then perform system equalization based on the spatial average of all measurement
locations. If a given measurement location is in close agreement with the spatial average, re-place
the microphone at this location and use this as a reference for conducting system eq. Another
useful approach: invert the spatially-averaged measurement curve then use this as a target while
electrically sweeping the equalizer. Alternatively, sweep the system equalizer while it is initally flat
then multiply by the spatially averaged curve. This allows you to adjust the equalizer while
monitoring the effect on the spatially-averaged response.
11) Duplicate eq settings for the other side of the system (if FOH L/R DSPs are not stereo linked).
Verify the effects of equalization by repeating steps 8-9.
12) Adjust the subwoofer level according to subjective taste a
nd
finalize EQ adjustments focussing
on the 120-300 Hz region.
14) Predelay the entire system to the desired time reference. For example, if the drum monitor is
the loudest element on stage, use a system with time delay measurement capability to measure
the time delay of the drum monitor with respect to the main system. Otherwise base system
predelay on the geometrically-determined delay.
15) Repeat the eq procedure for fill systems (LL, RR offstage arrays, front fill, centre cluster, etc)
16) Time align fill systems to the main L, R arrays by locating a measurement mic in the transition
region where the coverage patterns overlap.
17) Listen to a variety of familiar, well-recorded program material
18) Walk the room and attenuate fill arrays relative to the main L, R system as required
19) Compare program reproduced by the system versus a pair of high quality reference headphones
monitoring the output of the console.. Voice the system with a good quality vocal microphone.
20) Verify tuning throughout the audience by walking the room and perform final adjustments using
the analyzer between your ears!