User manual

4-4 E-PAC (V02) User Manual
No. of systems Level gain
10 dB
23 dB
35 dB
46 dB
68 dB
10 10 dB
Average level gain when using
multiple loudspeaker cabinets of the
same type.
4.4. Level setting of mid-high and SUB systems
With equal numbers of mid-high cabinets and corresponding
active subwoofers the input gains of TOP and SUB controller will
normally be set to the same level. This setting gives a correct
sound balance and matches the characteristics of the active
crossover filters in the controller modules.
Using different ratios of mid-high to subwoofer systems will affect
the relative levels between the systems which will require
correction using the controller module level controls.
The level gain by using multiple cabinets of the same type can be
evaluated with the table on the right or with the following
formula:
Level gain [dB] = 10 x log (number of systems)
Example: Using 10 subs together with 4 tops will give a level gain
of 10 dB in the sub range and 6 dB in the top range. So the SUB
controllers should be turned down by about 4 dB.
Relative to these nominal settings the balance between mid-high
and subwoofers should not be changed more than approx. 3 dB,
otherwise the crossover frequency between the systems is changed
and overall sound quality may be deteriorated.
With E3 systems the correct balance is obtained using a ratio of
two speakers to every subwoofer.
If the acoustic environment or the program material used requires
a severe correction in sound balance, it is much better to use an
external equaliser in the signal path before both the full range and
subwoofer systems so that the level correction is applied equally to
both systems. This allows the frequency response of the whole
system to be tuned without influencing the level, phase and
frequency response of the full range and subwoofer systems
relative to each other.
The sensitivity values quoted for the systems are also a useful
additional aid to relative level setting. The values in the technical
specification for each loudspeaker give the input signal level
expressed as the dBu value needed to produce a 100 dB (SPL)
sound pressure level measured at one metre.
Example: the E9 system input sensitivity for a 100 dB-SPL is –13
dBu, and that for the E3 system is –10 dBu. For equal sound level
from E3 and E9 loudspeakers used together, the E3 controller level
needs to be set 3 dB higher than that of the E9 controller.