52
Appendix
Lake LM Series Operation Manual Rev 1.3.5
Term
Description
Contour
Terminology given to a Frame or Module that denotes it is configured as a Loudspeaker Processor, normaly featuring crossovers and
multiple outputs fed from the same input.
Crossed Network Cable
An Ethernet cable in which four of the eight conductors (pins 1, 2, 5 & 6) are not wired pin-to-pin. Such a cable is required in conventional
IT networks to connect two PCs together without using a hub or switch. The auto-uplink feature of the Ethernet ports allows crossed
cables to be used if wished. See also Straight network cable.
Dante
A new-generation audio data protocol developed by Audinate
®
Pty Ltd, allowing multichannel high-resolution digital audio plus control
data to be transmitted via standard IT-industry networks using TCP/IP data packets. The Lake processing system integrated within the
LM Series device includes a dual-redundant Dante network interface, providing digital audio inputs and outputs via Ethernet.
dBu
dBu’s are usually used instead of voltages to describe signal levels in audio systems. A signal level of 0 dBu may be taken as 0,775 Vrms.
Delay
Up to two seconds of delay may be added to the input and/or output channels to time-align loudspeaker arrays.
Digital Gain Offset
Digital gain offset is effectively a ‘fine’ gain adjustment performed in the digital domain, which can be applied to digital input signals to
optimize the signal to the gain structure.
Distribution Amplifier
A distribution amplifier (usually abbreviated to DA) is an audio buffer stage – usually with zero gain – with one input and several outputs.
Mono, stereo and AES3 digital versions can be obtained. Use of a DA to feed a signal to several destinations ensures correct impedance
matching and isolation between source and destinations.
Dual-Network Topology
A network topology consisting of two (usually) identical networks, one connecting to the Primary Ethernet ports and the other to the
Secondary ports. Although more complex to implement, the advantage of using a dual-network system is one of greatly improved
reliability as one complete network remains operational if the other should fail.
Dynamic Function
Buttons
The six buttons around the front panel display are termed dynamic function buttons because their function varies depending upon which
display page is currently on-screen.
Electronic Balancing
In the analog domain, balanced inputs and outputs may be provided on audio equipment either by the use of transformers (traditional,
very good, but heavy and expensive) or via electronic balancing circuits (nearly as good, without full electrical isolation, but a great deal
cheaper).
Event Log
The details of any fault or warning conditions which arise in the device during operation are recorded in a data file created by the Lake
Controller software called the Event Log.
Fault
A Fault in the device occurs when one of the operating parameters exceeds pre-determined safety levels, or when a condition is
detected that otherwise seriously affects the performance. Some fault conditions may result in one or all of the channels being muted.
FIR Filter
Finite Impuse Response Filter. An alternative design of crossover filter realisable in the digital domain, providing linear phase
characteristics. FIR filtering is provided in all Lake devices.
Floating
An analog balanced input or output is said to be floating when full electrical isolation exists between that input or output and the equip-
ment connected to it. Transformer-coupled inputs and outputs are inherently floating. Electronically balanced inputs and outputs can
never be truly floating, though better designs – such as that found in LM Series devices - do mimic the characteristics of transformer-
coupled designs to a high degree.
Frame
Lake terminology for a physical unit containing a Lake processing system (i.e. a single LM or PLM Series device, or legacy Lake
Processor).
Frame ID
An electronic identification ‘label’ which can be given to each Frame in an amplification system. Naming Frames in a large system is
desirable as it simplifies identification in the Lake Controller.
Frame Preset
Frame Presets are a class of Presets within the Lake processing system. Up to 100 can be stored in the hardware device, and each holds
the complete configuration of all Modules and the Modules’ internal settings.
Gigabit Ethernet
Describes the speed of Ethernet data transfer for devices that transmit Ethernet frames at a rate of a gigabit per second, as defined by
the IEEE 802.3-2008 standard.
GPIO
The General Purpose Input/Output (GPIO) port on a LM Series device allows two-way communication with external devices for certain
functions.
Hub
A type of network interface device with multiple Ethernet ports. Data arriving at any port is sent to all others. Hubs have been largely
replaced by Switches.
Input Level
The amplitude of an audio signal at the point where it is applied to the input of the device, or at the input of an intermediate stage within
it. An analog input signal level will be expressed in dBu’s, while a digital input signal level in dBfS (dBs below digital clip level; fS =
full-scale)
Input Router
The Input Router allows automatic or manual selection of any device input to be allocated to a Module Input or directly to any output.
The Input Router is effectively an intelligent digital patch bay & automated switch that can seamlessly failover to up to four levels of
inputs in the event of digital signal loss. The output from the router is the input signal from a valid input with the highest priority.
IP Address
Every item of equipment connected to an Ethernet network has a unique address called the IP address, so that data gets to the correct
place. IP addresses are written as four groups of three decimal numbers between 0 and 255. In a system consisting of Lake Processors
and a Lake Controller they are assigned and detected automatically.
IP Subnet Mask
IP subnet masks are required in all IP networks. The subnet is determined by the size and type of network being used. For small
networks (less than 254 addresses) a subnet mask of 255.255.255.0 can be used. (A Class C network).
Iso-Float
Iso-Float is Lake’s proprietary method of electronic balancing, which provides a particularly high level of isolation and immunity from
ground loops.
Lake Controller
The Lake Controller is the software application used to control LM and PLM Series devices and legacy Lake processors. This software
application provides additional functionality and allows various grouping functions for simultaneous control of multiple Lake Processing-
enabled devices.
Latency
The small but finite delay incurred by audio signals when they are transformed into the digital domain, processed digitally and then
converted back into analog signals. In the Lake system, latency is assured to be constant.
