Rane THX Room EQ - Manual (Page 19)

Home THX Equalization Manual Rev. 1.5
19
2.7) Subwoofer Equalization:
All Subwoofer measurements should be done using the Center Channel Pink Noise band on
“Wow!” (Chap. 9) or with your pink noise source into the Left and Right inputs of the decoder. Disable
or disconnect the LCR speakers.
Unequalized Subwoofer Room Response
Frequency Hz
dB
SPL
60
65
70
75
25 40 63 100 160 250 400 630 1000 1600 2500 4000 6300 10000 16000
Fig 12
Measuring the Subwoofer is very similar to measuring the LCR channels with one exception.
Because the pink noise source will exhibit larger instantaneous fluctuations in amplitude at lower
frequencies (see the section on pink noise in the introduction), more averages will be necessary to
improve measurement consistency. It is therefore recommended that, rather than attempting to
spatially average the microphone positions with a non-multiplexing RTA, you take the maximum num-
ber of readings at Position 1 that you can store and average them. Then adjust your EQ setting for flat
response for that average.
If you are using “Wow!” as the pink noise source, use the Center Channel Pink Noise (Chapter 9).
Otherwise connect your pink noise source into the both Left and Right channel inputs of your decoder.
When equalizing the Subwoofer Channel, you should concentrate on reducing the serious peaks.
You may find that because of the depth of the room modes a ruler flat response is not within the range
of the equalizer. This not a major concern since a response within ± 3 or 4 dB is very acceptable.
One tip — a reduction of energy in the 20-30 Hz range will enable the subwoofer to play louder without
before encountering excursion problems.
Reconnect your front speakers.