Sp2120, Chapter 1, Drawmer – Drawmer SP2120 Speaker Protector User Manual

Page 3: Introduction, Speaker protector

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The Drawmer SP2120 Speaker Protector offers both strict
level control and tremendous peace of mind to the con-
tractor, installer and venue in the knowledge that, as its
name suggests, the 1U, two channel processor eliminates
the possibility of ’unauthorised’ excessive sound pressure
levels on speaker systems (as caused by spikes and pops
in the system, or by over-enthusiast dj’s/engineers) which



could result in damage to both chassis drivers and ampli-
fier electronics. In addition only the maintenance engi-
neer and the venue manager hold a key. The unit also
gives a wide variety of venues, such as clubs, theatres,
pubs, schools, universities etc. the opportunity to comply
with the local legislation regarding noise levels.

The key features are as follows:

• Key Holder access only

• Takes only minutes to install

• Tamper-Proof bracket (available separately) to lock-in the XLR’s and conform to Local Authority regulations.

• Dual 16 segment Left/Right bargraphs for ’at a glance’ level metering

• ’Protection’ processing 16 segment bargraph display

• No sound quality loss even during heavy protection processing

• Once installed and calibrated completely eliminates the possibility of ’unauthorised’ volume levels

• Eliminates sound system abuse and the resulting cost of chassis speaker re-cones, HF diaphragm

replacements and amplifier repairs.

• Reduces ’call-out’ costs of sound system service/repair engineers

• Reduces sound system ’down time’ and the consequential loss of venue income

• Isolation transformer output option.

The SP2120 front panel features an integral security lock
to ensure that adjustments to maximum volume levels are
implemented by key holders only. In ’unlocked’ mode two
front panel pre-sets are exposed and available for
adjustment by the installer. The first calibrates the 16
segment Left/Right bargraphs to the incoming audio and
dictates the point at which ’protection’ processing
commences. The second sets the absolute volume level
to which the sound system is allowed to perform. If the
SP2120 receives increased signal levels, the transparent
’protection’ circuitry is activated which maintains the
specified system volume level without degradation in sound

The SP2120 greatly benefits from Drawmer’s 25 years
experience in designing industry standard dynamic
processing devices. Its signal path combines a mixture of
’multiple time constant’ circuitry and automatic gain control
(AGC) which allow small overloads to sound louder – even
though they’re not.

Its concept and development was encouraged by Drawmer
distributors and installers dissatisfied with other protection
systems currently available. These often take the form of
a crude switch, either turning off the power or disconnecting
the speakers, both of which are ’disruptive’ in any event.

This manual is related to the following products: