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3.1 GENERAL DESCRIPTION OF XT PRESETS
For 2-way operation, three types of presets are provided:
FRONT presets are for standalone FOH operation (without subwoofers) where low and high
frequency shelving equalization provides a frequency response contour suitable for music
applications.
FILL presets provide nominally flat response for use in speech reinforcement and classical music
applications or when XT enclosures are used as a close proximity fill enclosure.
FRONT and FILL presets are derived under freefield measurement conditions.
MONITOR presets include additional low frequency equalization to account for half-space
loading conditions and are intended for floor monitoring applications or fixed installations where
the XT is wall- or ceiling-mounted.
MONITOR presets are derived under half space measurement conditions.
A variety of 3-way presets are provided for use of 112XT or 115XT loudspeaker enclosures with
SB115, SB118, SB218 or dV-SUB subwoofers. Standard 3W presets utilize a complimentary 100 Hz
crossover point for the XT and its companion subwoofer and are recommended for closely coupled
applications. Alternatively, when XT enclosures are flown and subwoofers are ground stacked, 3WX
presets can be employed where an 80 Hz low pass filter is applied to the subwoofers and 112XT or
115XT low frequency response extends to 55 or 50 Hz, respectively.
3.2 XT PRESET POLICY
According to L-ACOUSTICS policy, key parameters are software-protected and preset data or
passwords are not available in order to preserve quality control, confidentiality and to maintain the
integrity of L-ACOUSTICS system presets. Restricting access to presets is in no way meant to restrict
flexibility or the creative process – on the contrary, software-protected presets are intended to
enhance creativity by ensuring quality control and repeatability.
Extensive engineering and real world testing goes into determining optimum presets – detailed polar
measurements and weighted spatial averaging are used to determine component equalization, time
alignment, crossover points and crossover filter slopes, for example. As a result, L-ACOUSTICS
presets give the user an optimum starting point – system tuning should be done using band
attenuation, subwoofer time alignment and system equalization using input section parametric filters –
not by altering presets for the following reason:
Without proper instrumentation and spatial averaging, adjustments made at one location (e.g. the mix
position) are not optimum at all other locations within the defined coverage region of the system.
When made by ear, such adjustments are often misguided – the user may be in a local room mode
(low frequency pressure maximum or minimum) and/or may be hearing a cancellation or addition due
to crossover misalignment that sounds good at that specific location but what about all others?
Meanwhile, the same result could have been achieved while preserving the power response of the
system by using the correct crossover preset and a simple equalization cut or correct time alignment
of subwoofers.
Preset libraries are distributed via PCMCIA Card which are available from L-ACOUSTICS
headquarters in France , L-ACOUSTICS US, L-ACOUSTICS UK or your L-ACOUSTICS distributor.
Preset libraries and upgrades can also be downloaded from www.l-acoustics.com.
L-ACOUSTICS XT Manual V1.1
2/11/2003
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