L‑ISA Live

Performing Zone

The performing zone is the portion of the stage occupied by performers during the show. It is the primary focus of L-ISA Live to offer a faithful reproduction of the action that takes place in the performing zone.


Fusion is the ability to merge a sound source with its visual counterpart within the performing zone, such as a performer. It relies on the sound system ability to create localized separate sources, “What you hear is what you see”.


Localization is the ability to assign a precise position to each sound source. Good localization is a primary requirement for fusion and separation both in the horizontal and vertical dimensions.


Separation is the ability to isolate individual sound sources within the soundscape. separation is improved if individual sound sources have a precise localization.


Intelligibility is the sound system capability to enable the listener to pick out subtleties in program material, such as speech and lyrics.


Coverage is the area where the sound level distribution of the system is homogeneous over the operating frequency range. Matching the coverage of all the system speakers allows maintaining the level of each sound source independently of the localization.


Hyperrealism is a genre of visual art introduced in the 70s. Coming from Photorealism, it represents forms and shapes with an extreme resolution. Applied to sound, it requires the sound design to deliver extreme coverage, localization and impact over a large area, enabling perceptual fusion, separation and intelligibility for the members of the audience.


Panorama is the maximum opening angle of the sound system.


Envelopment is the degree to which the audience feels a room effect due to natural and/or electronic reflections and reverberation.


Immersion combines panorama and envelopment. It is the feeling of being part of the experience.

Sonic Performance

Sonic performance relates to the quality of sound in the audience in terms of SPL performance, distribution and profile, impact, and frequency contour.

Frequency Contour

Frequency contour relates to the frequency response of the sound system in relation to a reference curve.


Impact relates to the temporal integrity of the sound. Impact is impaired by the dispersion over the audience of the respective contribution of the speaker groups that radiate the same signal from different locations.

SPL Profile

The SPL profile describes the variation of sound pressure level along the depth of the venue. For each speaker group, a curve representing the level of SPL in the 1-10 kHz band expresses the way that the SPL evolves in the longitudinal section of the audience from the first row to the last.

L‑ISA Live Implementation


The scene system is set to match the actual width of the performing zone. The scene system amplifies the action on stage through a linear pattern of equally spaced identical speaker groups.

Wide Design

The L-ISA Wide design: The Scene sources are all identical arrays evenly spaced across the stage. This design is adapted to a majority of music content including jazz, classical, speech, adult contemporary.

Focus Design

The L-ISA Focus design (patent pending): The Scene system dimensioning is optimized to reproduce high LF contour program material. This design is adapted to rock and electronic music.


The extension system expands the soundscape beyond the performing zone up to the side walls of the venue.


The frontal system is the combination of the scene system and the extension system.

L‑ISA Zone

The L-ISA Zone is the area of the audience that is within the coverage area of all speaker groups in the scene system. The L-ISA Zone defines the audience area that benefits from a hyper-realistic immersive experience.


The surround system consists of identical speakers distributed at the periphery of venue.


The overhead system consists of a small number of identical speakers distributed above the frontal audience or middle audience.

Near Fills

The near fills system achieves coverage of the area close to the stage.

Out Fills

The out fills system achieves coverage of extreme lateral areas.

Delay Lines

The delay lines system achieves coverage of masked or far areas.

L‑ISA Live Certification Criteria

SPL Max Average

The SPL max average is the average maximum SPL expressed in dBA (A-weighting).

SPL Distribution

The SPL distribution evaluates the consistency of the Coverage over the audience.


The time criterion evaluates the impact of the sound over the audience. The time criterion is defined as the portion of the audience that shows good temporal integrity of the sound in relation to the respective contributions of the multiple speaker groups that radiate the same signal from different locations.

L‑ISA Zone

The L-ISA zone criterion describes the ratio of the L-ISA zone extension over the entire audience area.

Spatial Resolution

The spatial resolution criterion reflects the density of speaker groups in the scene system.

Horizontal Localization

The horizontal localization criterion evaluates the ability of the sound design to achieve Fusion in the horizontal dimension and create smooth trajectories.

Vertical Localization

The vertical localization criterion evaluates the ability of the sound design to achieve Fusion in the vertical dimension.


The immersion criterion describes the potential of the sound design to provide a high degree of immersion for a frontally oriented Live act.