L-Acoustics LA4 User Manual

Preset design
Preset design
Gain structure
The gains of all L-Acoustics factory presets are calibrated with a reference pink noise signal, representative of most
demanding musical programs. The reference input level is 0 dBu (with analog audio source) or -22 dBFS (with digital
audio source).
When feeding L-Acoustics amplied controllers at this input level, L-Acoustics loudspeaker enclosures provide the sound
engineer with 8 dB of headroom, except for smaller formats calibrated for 4 dB of headroom (MTD108A, 5XT, X8, 8XT,
Kiva, Kilo).
This gain structure helps managing power resources of L-Acoustics systems when using different enclosures of the same
format. With default output gain settings (0 dB), all enclosures reach their limits for the same program level. Apply a gain
adjustment of -4 dB for smaller format enclosures when used along with bigger format L-Acoustics enclosures.
Headroom for SB15m
SB15m presets [SB15_100] and [SB15_100_C] have 8 dB of headroom from preset library version 5.6(.5).
[SB15_100_Cx] has 8 dB of headroom.
4 dB of headroom are provided when using presets from earlier versions and preset [KIVA_SB15].
Headroom for K1-SB, KS28, SB28, SB18, SB218 and SB118
To provide 8 dB of headroom, the output gain of some subwoofer presets is adjusted in preset library 6.0
compared to previous versions.
This update aligns the L-DRIVE activity between subwoofers and full range loudspeakers for the same reference
pink noise signal.
When updating presets in Session les using older versions of the preset library, adjust gains as follows to keep
the same gain chain:
[SB28_60], [SB218_60]: + 4 dB
[KS28_60], [SB_28_100], [SB18_60], [SB18_100], [SB218_100], [SB118_60], [SB118_100]: + 3 dB
[KS28_100]: + 2 dB
[K1SB_60]: + 1 dB
Electro-acoustic coupling
Each recommended loudspeaker conguration provides a coherent sound source, by implementing a loudspeaker system
in a specic deployment pattern and with dened factory presets.
L-Acoustics factory presets ensure the coupling between the different transducer sections, whether it is internal coupling as
in active loudspeaker enclosures, or external coupling as when several loudspeaker enclosures are combined.
Users can adjust preset parameters on top of factory settings and for predened channel sets.
Channel sets have been dened for the presets dedicated to active loudspeaker enclosures and to some specic
loudspeaker congurations. A channel set maintains a coherent coupling by linking several output channels for the setting
of routing, gain and delay parameters. For example, [LF HF] is a channel set for 2-way loudspeaker enclosure presets,
and [SRSBSBSB] is a channel set for cardioid subwoofer presets.
The Preset Guide describes the recommended loudspeaker congurations for each system, with the corresponding factory
presets and the main resulting acoustic properties.
When applicable, refer to the user documentation of the related system for the limit between coupled and separated
subwoofers.
For some loudspeaker enclosure combinations, it is necessary to adjust the delay values for time-alignment. Refer to
section Pre-alignment delay values (p.66).
6 Preset Guide owner's manual (EN) version 16.0

L-Acoustics LA4 Specifications

General

Brand	L-Acoustics
Model	LA4
Category	Amplifier
Language	English