Sony DFP-R3000 Quick Start Manual page 15

This procedure, which requires an RTA, matches the playback gain of the digital
subwoofer loudspeaker in the cinema to the playback response of the subwoofer (LFE
loudspeaker) on the stage where the film's sound track was mixed. Be sure to allow
extra time for the low frequency bands to settle to their final values.
When evaluating the SDDS digital subwoofer (LFE) level, no listening test is entirely
definitive, because the amount of energy in the LFE channel is a creative decision made
when the soundtrack of each film was mixed. For the same reason, the digital
subwoofer (LFE) low pass filter setting has no relationship to the screen loudspeakers'
performance. It merely serves to exclude undesirable sound from the subwoofer (LFE)
cabinet. The actual sounds reproduced on the digital subwoofer (LFE) channel are
determined by what is put there by the film's sound mixer, as long as the filter
frequency is not set so low as to remove sounds the mixer intended to be included.
Setting the digital subwoofer (LFE) low pass filter frequency to 100 to 200 Hz should be
acceptable and should sound the same when actual film is exhibited; start with 160 Hz.
Subwoofer manufacturers may have specific recommendations for their cabinets.
Note that the result of a wideband SPL measurement of pink noise from the SDDS
subwoofer (LFE) will depend on both the level Trim setting and the low pass filter
frequency setting. For a LPF frequency setting of 100 Hz, a wideband measurement
made with an SPL meter will show approximately 91 dB. Such a measurement should
only be made to confirm that a correctly calibrated theatre has not drifted, and cannot
be used as a primary calibration measurement in place of an RTA. Also remember that
the analog subwoofer channel trim is effectively in series with the subwoofer amplifier's
input gain control. This means that an adjustment to the analog subwoofer channel trim
also affects the playback level of the digital subwoofer (LFE) signal.
Note that the graphic and parametric equalizer settings
adjust for the frequency response of each of the
loudspeakers in the theatre. They are retained in the
DFP-D2500's non-volatile memory as a single set of overall
adjustments to the playback system, unless the EQ/Channel
level trim button is un-ticked. Other settings, such as
surround speaker delay and preset trim, may be
characteristic of one of the presets/inputs, so they are stored
individually within each of the two presets.