LSP-1 Speaker Processor
Owner's Manual v 2.2 ©2000 ARX®
LSP-1 Speaker Processor
Owner's Manual v 2.2 ©2000 ARX®
6
3
Introduction
Thank you for choosing this ARX speaker system. We understand that you are keen
to use your new purchase, but before you do, and to ensure continued trouble free
use, please familiarise yourself with the contents of this owner's manual before
plugging any leads in or connecting up to AC power.
In particular, pay
close
attention to the section on connecting the I.S.C. leads to the
processor. The colour code and channel selection is particularly critical when
putting the system together for the first time.
Severe speaker damage
can be caused by
incorrect wiring, and is not covered by the terms of your warranty. So please, take it
easy and check things as you go.
What is I.S.C?
I.S.C stands for
Interactive System Control
, ARX’s innovative Speaker and Electron-
ics Interface.
There is a lot of hyperbole attached to the
Electronic Processing of speaker systems, but
if we look at what’s happening in an purely
audio electronics context, we find that
irrespective of the name attached to this style
of Speaker System they all basically perform
the same functions.
The Basic Principles of Feedback
style Gain Control
ISC monitors the output of the power amplifier driving each set of Loudspeaker
components and compares this signal with an internal model of the SOA (safe
operating area) of the driver. When the signal applied to the driver tries to exceed
that SOA, the signal is limited or held at a level which is safe for the driver to
reproduce. As the driver signal forms part of a feedback style loop this SOA can
never be exceeded.
Why monitor the outputs of the amplifiers?
What interests us is the actual power being applied to loudspeaker components, not
the signal being applied to the input of the Power Amplifier. To measure this
accurately and allow the user their personal choice in Power Amplifiers we have to
go where the action is - the outputs of the amplifier. This is used as the reference.
What size amplifier do I need?
You’ll notice that on all ARX speaker system spec sheets we quote a “recommended
minimum amplifier size” - we don’t quote power handling. The ISC processor
determines the amount of power supplied to each speaker, ensuring this remains
within the SOA of the driver. But by recommending the minimum amplifier size we
are indicating that this is the
least
amount of available power required for ISC to
operate in the way it was designed by ARX engineers.
Where do I put the processor?
The processor is mounted with the Amplifiers in the amp rack. In most applications
once the main frequency response balance is set, system equalization is achieved by
a Graphic or Parametric Equalizer, so there is no need to constantly access the
processor.
Plug-In Parameter card modules
The
LSP-1 Low Frequency Loudspeaker Processor
is a general non-Model-specific
Loudspeaker Management Platform.
The variable parameters required for each model, such as High Pass Filter, Frequen-
cy Response Contour, Phase Response
and Loudspeaker Component Power
Handling Limits are all set on our new “Plug in Card” system.
Each ARX Loudspeaker model now has its own dedicated Preset Card, ensuring
predictable performance and the ability to update Loudspeaker Performance simply
by plugging in new PCB cards.
This ‘user-friendly’ innovation enables easy re-configuration for different ARX
Loudspeaker models without the need to remove and replace components on the
unit’s Printed Circuit Board.
The LSP-1 Loudspeaker Processor can also be supplied calibrated to other manufac-
turer's (non ARX) speaker systems. For full details see our “Custom Plug-In Card
Technical Parameters’ fact sheet.
The following Model numbers apply:
Loudspeaker Model
Processor Platform & required Module Card
for
925
Loudspeakers order
LSP-1/M925
for
218
Loudspeakers order
LSP-1/M218
for
118
Loudspeakers order
LSP-1/M118
for user defined system order
LSP-1/MOPEN
The module cards are also available separately and can be ordered by using the
following model numbers:
for
925
Loudspeakers order
M925
for
218
Loudspeakers order
M218
for
118
Loudspeakers order
M118
for user defined system order
MOPEN
