User`s manual

B-Chain Alignment Procedures
Notes
5-13
5.2 Setting Room Equalization
Adjust the treble controls on the EQ board for as flat a response as possible
up to 2 kHz, followed by a 3 dB per octave roll-off above 2 kHz.
The right hand H.F. control sets the frequency range. The left hand H.F.
control sets the boost or cut.
The next step is to fine-tune the equalization by adjusting the EQ controls on
the EQ board. There are certain rules to keep in mind:
• All of the equalizer controls interact with each other so you should not start at
the low end of the response curve and merely work your way to the high end.
As each control is adjusted, the response obtained by adjustment of adjacent
controls is affected.
• Start at the center frequency and attempt to achieve results with cut rather
than with boost. The desired curve is a flat frequency response up to 2 kHz,
falling at 3 dB per octave to 8 kHz (1 dB per third-octave band).
• If modern woofer systems (vented-box direct radiator enclosures) are installed
in the theatre , moderate bass equalization down to 40 Hz may be used.
• Once an adjustment seems OK, work on the frequencies to either side of it.
You may find that a cut at one frequency is followed by a slight boost at
adjacent frequencies.
Although the equalization may be set correctly for the chosen microphone
position, it still may not be correct for providing the best sound to the
greatest number of seats in the theater. You should therefore check the sound
quality at several locations (three or more) in the auditorium with the
calibrated microphone and RTA system. If time does not permit this
procedure, walk around the theater with pink noise playing. If necessary,
adjust the equalizer for a compromise at several seat positions so that all of
them sound acceptable.
Mark the settings for each control on the white card provided.