Rane THX Room EQ - Manual (Page 20)

Home THX Equalization Manual Rev. 1.5
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2.8) Confirm the Subwoofer Splice: Center Channel
The next step is to activate the internal test signals present in your Home THX Controller and re-
adjust all SPL’s to their correct 75 dB C weighted levels. This will even out any level variations intro-
duced by equalization.
After level check, return to your “Wow!” Center Channel pink noise; Chapter 9. Observe on your
RTA the relative levels of the Subwoofer and the Center Channel. The overlap area is referred to as
the splice point. Follow the same averaging procedure you used for Subwoofer EQ. In particular, look
at the crossover area between 80 Hz and 200 Hz. This area will usually appear uneven (Fig. 13).
Uneven Subwoofer Splice
Frequency Hz
dB
SPL
60
64
68
72
25 40 63 100 160 250 400 630 1000 1600 2500 4000 6300 10000 16000
Fig 13
The most common cause of an uneven Subwoofer splice is the relative difference in positions between
the LCR speakers and the Subwoofer(s). These position differences can cause frequencies common
to all the speakers to arrive at different times at the listening position, and partially cancel or reinforce
themselves. At this point use the Center Channel EQ to adjust the response at the splice. DO
NOT use the Subwoofer EQ .
2.9) Confirm Subwoofer Splice: Left and Right Channel
Next, in the Stereo or Bypass mode play both the Left and Right Pink Noise from “Wow!”; Chap-
ters 8 & 10. Adjust both the Left and Right Channel splices to the Subwoofer channel by using your
Left and Right Channel EQs.
Remember, if the relative levels are off, use your Home THX Controller to adjust the levels. Use
the Left, Center, or Right EQ controls only to adjust for uneven frequency response at the
splice point.