Skip to content
TechnoGuru — Think Technology, Think TechnoGuru

— Speaker Coverage · Ceiling 100V

JBL Professional Control 26CT: SPL & coverage

Problem. A 15 x 10 m restaurant relying on background music needs to know whether a single ceiling cabinet keeps speech-and-music levels comfortable at typical table distances, not just how many boxes fit the floor plan on paper. The Control 26CT's rated output and dispersion answer both the SPL-adequacy question and the physical coverage-coverage question for this specific cabinet before layout is finalised.

Answer. For the restaurant-bgm scene at a 4 m listener distance and 50% drive, the Control 26CT delivers approximately 92 dB SPL, comfortably within a background-music target. Its 110 x 110 degree dispersion gives a horizontal (-6 dB) coverage half-width of approximately 5.7 m from a single ceiling position.

02 / In depth

How this preset reads — the engineering view.

The Control 26CT is rated 107 dB maximum SPL at 1 m. Because sound pressure falls with distance under the inverse-square relationship, that figure drops to approximately 95 dB at 4 m when driven at full output, and to approximately 92 dB at 4 m when the planner's drive level is set to 50 percent.

The cabinet's 110 x 110 degree (H x V) dispersion is what sets the approximately 5.7 m horizontal coverage half-width at the -6 dB threshold used by the planner. This wide, symmetrical pattern favours even near-field fill under a single ceiling point rather than a tightly thrown beam. Control 26CT is a passive cabinet, so it always needs a matched amplifier channel rather than built-in electronics.

In the planner, drag the listener-distance and drive-level controls to watch the SPL readout move in real time. The suggested box count compares the room's width subtend against the cabinet's horizontal dispersion; SPL adequacy at the chosen listener point is a separate feasibility check, and both should read acceptable before treating a layout as workable.

The planner does not model room reverberation or RT60 decay, coverage zoning across separate seating or bar areas, subwoofer pairing for low-frequency extension, mechanical rigging for arrays, or DSP/delay tuning between multiple ceiling points. Treat its output as a first-pass coverage and SPL check, not a substitute for an on-site acoustic review of the finished space.

What this preset deliberately does not solve

  • SPL figures are free-field inverse-square estimates from the rated 1 m sensitivity; real rooms with reflective or absorptive surfaces will read somewhat higher or lower than the planner's number.
  • The 5.7 m coverage half-width assumes a single ceiling-mounted cabinet aimed straight down; angled mounting, obstructions, or ceiling height outside a typical range will change the effective footprint.
  • The planner checks coverage and SPL only; it does not verify amplifier channel matching, cable runs, or ceiling-tile mounting compatibility for this cabinet.

How this preset differs from its siblings

Other ceiling 100V cabinets in the catalogue trade off maximum SPL, dispersion angle, and cone size differently, so the same room and listener distance can land at a different feasibility outcome. The Control 26CT's 107 dB rating and 110 x 110 degree pattern sit toward the wider-coverage, moderate-output end of that range, making it suited to even background-music fill in modest-sized rooms rather than higher-SPL foreground playback. This preset exists because swapping in a narrower or higher-output cabinet on the same 15 x 10 m room changes both the box count and the SPL margin, and visitors searching for this exact model need the numbers for this cabinet, not a generic ceiling-speaker estimate.

02 / What that means, drawn

Plan view, drawn to one scale in both directions. The room is 15.00 m deep by 10.00 m wide, with the cabinet on the front wall and the listener 4.00 m down the axis. JBL Professional Control 26CT has a nominal horizontal pattern of 110°, so the covered shape is a wedge whose apex is at the CABINET, not a circle around the listener. The wedge is drawn at half that angle either side of the axis. At the listener's distance that wedge is 11.43 m across — 5.71 m either side of the axis. That width is the published figure, and it is the only coverage quantity this tool establishes. The room is 10.00 m wide there, so one cabinet covers the full width with 1.43 m to spare across the two edges combined. The wedge is the nominal beamwidth drawn with straight edges. It is not a measured -6 dB contour, and it is a HORIZONTAL quantity only: no vertical coverage, and no covered area, is claimed here. This cabinet's vertical pattern is 110°, and the difference between the two is exactly why a single circular figure would misstate the covered patch.

This preset’s geometry, drawn to one scale in both directions from the same derivation the calculator below uses. The wedge is JBL Professional Control 26CT’s nominal 110° horizontal pattern, not a measured contour, and no vertical coverage or covered area is claimed. Move the controls below to change it.

03 / Hydrated calculator

Try the configuration — live.

The calculator below is preloaded with this preset’s state. Adjust any input — your URL stays shareable.

Loading the calculator…

· Other presets for speaker coverage planner

Already own one ·

Look up where the JBL Professional Control 26CT sits in its lifecycle

Delivered as a service ·

Professional Audio & PA SystemsHospitality Venue AVAuditoriums & Boardrooms

Compare the options ·

Architectural audio vs conventional loudspeakers — the design approach70V/100V distributed audio vs low-impedance audio

· Next

Brief us on the project — with this configuration.

Presets are a typology starting point. The brief wizard captures the room geometry, programme and constraints we need to translate this configuration into a real design.

Open in the toolSend the brief