Genelec Loudspeaker Manager (GLM) 4 - System Operating Manual
page 77 of 87
10.4 Level-Aligning Subwoofers Reproducing the Same Signal
When several subwoofers reproduce the
same channels
, the low frequency output by those
subwoofers will sum and elevate the output level. After the AutoCal and AutoPhase, the output
levels of all the subwoofers reproducing the same signal must be adjusted down. An example of
this situation is when subwoofers are daisy-chained to reproduce the same
sum
signal or LFE
signal.
To setup a daisy-chain of subwoofers, perform following steps:
Run AutoCal and AutoPhase – this sets each subwoofer individually
Find the correction level in the Table 5 corresponding to the number of the subwoofers in
the daisy-chain.
Edit the Acoustic settings of each subwoofer. Reduce the ‘Level Compensation’ value
according to the correction provided in the Table 5. Press the ‘Confirm’ button to save the
new settings. Repeat this for all the subwoofers in the daisy-chain.
Table 5. Subwoofer level corrections for daisy-chained subwoofers.
Number of subwoofers
in the daisy-chain
Correction
(dB)
1
0
2
-6
3
-9
4
-12
5
-14
6
-16
Figure 44 shows the Level Compensation field where the Autocal calculated single subwoofer level
is shown. For the case of two daisy-chained subwoofers reproducing the same signal, this figure is
reduced by 6 dB (see Table 15). Click ‘Confirm’ to accept the change. This completes the setting
for this particular subwoofer. Do the same level reduction also for the next subwoofer.
Figure 44. Level compensation setting in the Acoustic Editor.
The level correction for subwoofers are only required if those are reproducing same channels.
Audio connections for analog signale is show in Figure 45 and for AES/EBU signal in Figure 46. If
subwoofers are used so that the left subwoofer only reproducing the left channel and the right
subwoofer only reproducing the right channel, level corrections won’t be needed.
