5-4
A1 User Manual
5.3.
Level setting for mixed systems
A mixed system is one which uses a mixture of full range cabinets
and subwoofers. If equal numbers of full range cabinets and sub-
woofers are used then the correct balance and crossover frequen-
cy between the full range and subwoofer systems is assured provi-
ded the recommended controller module level settings are used.
These recommended settings, using various d&b subwoofer sy-
stems, are given in the sections of this manual describing the F1220
and F2 loudspeakers. Altering the ratio of full range to subwoofer
cabinets in a mixed system will need to be corrected by adjusting
the controller module level controls.
Extreme differences of level settings between full range and sub-
woofer systems should be avoided. Differences of more than ap-
prox. 3 dB will adversely affect the crossover frequency between
the systems and produce a deterioration in overall sound quality. If
- to achieve a better balance - a severe correction is neccessary,
its much better to use an external equaliser in the signal path be-
fore both the full range and subwoofer systems so that the level
correction is applied equally to both systems. This allows the fre-
quency response of the whole system to be tailored to the acoustic
environment without unduly influencing the level, phase and fre-
quency response of the full range and subwoofer systems relative
to each other.
The sensitivity values quoted for the systems are also a useful addi-
tional aid to relative level setting. The values given in the technical
specification for each loudspeaker give the input signal level ex-
pressed as a dBu value needed to produce a 100 dB (SPL) sound
pressure level measured at one metre.
Example: the 1220 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 1220 loudspeakers used together, the 1220-CO level
control needs to be set 3 dB lower than that of the E3-CO.
