PLM Series Operation Manual rev 1.1.3
8. Signal Flow and Processing
35
The Lake Processing system provides two distinct categories of crossovers:
Infinite Impulse Response filters (IIR) such as the classic Bessel, Butterworth or Linkwitz-Riley types;
▸
these are available with slopes ranging from 6 dB/octave to 48 dB/octave.
Finite Impulse Response filters (FIR) providing zero phase shift with steep transition slopes at the
▸
crossover frequencies. These are also referred to as Linear Phase Crossovers.
Details of how to configure the Lake Processing system can be found in the Dolby Lake Controller User
Manual.
8.3 Modules and Frames
A
Frame
represents one physical PLM on the network. A maximum of two Modules are contained within
each PLM Frame; these are referred to as
Module A
and
Module B
. The number of Modules shown in a
given Frame is dependent upon the signal processing configuration of that Frame.
Modules can be configured with the following processing elements, either singly or in combination:
Classic Crossovers (Bessel, Butterworth, Linkwitz-Riley)
▸
Linear Phase Crossovers
▸
Auxiliary Outputs.
▸
The Lake Controller software is also provided as standard with a PLM LoadLibrary of Modules pre-
configured for many well-known models of loudspeaker.
Module file types available on the PLM are:
Notation*
Description
1
1 Auxiliary Output
2
Classic 2-way crossover or 2 Auxiliary outputs
2+1
Classic 2-way cro 1 Auxiliary output
LP2
Linear Phase 2-way cro 1 Auxiliary output
3
Classic 3-way crossover or 3 Auxiliary outputs
3+1
Classic 3-way cro 1 Auxiliary output
LP3
Linear Phase 3-way crossover
4
Classic 4-way crossover or 4 Auxiliary outputs
LP4
Linear Phase 4-way crossover
5**
Classic 5-way crossover or 5 Auxiliary outputs (see Note)
6**
Classic 6-way crossover or 6 Auxiliary outputs (see Note)
Note: *designation as seen on Lake Controller Module display.
Table 8.3: PLM Module file types