Speaker Coverage Planner — Frequently asked

Inverse-square law from the cabinet's rated maximum SPL: SPL(d) = maxSPL − 20·log10(distance/1 m), plus a drive-level term of 10·log10(drive%/100). A 130 dB cabinet at 8 m: 130 − 20·log10(8) = 130 − 18 = 112 dB at full drive. The calculator runs this exact math — it works from each model's published maximum SPL, not from a sensitivity-plus-wattage computation, because amplifier power and sensitivity are published inconsistently across brands while max SPL is near-universal. Its limits: it assumes free-field propagation (no room reflections), single-cabinet contribution (no array summation), no air-loss at high frequencies, and the manufacturer's rated maximum SPL (whose measurement convention — peak vs continuous — varies by brand). For final venue design, manufacturer prediction software (Soundvision for L-Acoustics, ArrayCalc for d&b, K-array proprietary) models all of these and produces per-seat SPL maps.

Because line-array geometry exists to control vertical coverage taper across audience depth. Each cabinet narrowly aims a slice of the seating; assembling 6-12 cabinets in an array creates continuous vertical coverage from front-row to back-row, with each cabinet's vertical splay calibrated so that distant rows receive the same SPL as close rows. Wide vertical dispersion would put energy on the ceiling and the floor — wasted energy that returns as reverberation. The narrow vertical control is the engineering value of line array.

Touring brands (L-Acoustics K-Series, d&b V/Y/J, K-array Mugello, JBL VTX) prioritise SPL output, transport durability and rapid rigging; they cost more per box but justify it on tour. Install brands (L-Acoustics A-Series, d&b Y/E-Series, K-array Pinnacle, JBL VRX/AC) prioritise low visual profile, longevity in fixed installations and cost-per-seat efficiency. For permanent worship and auditoria, install tiers are usually correct. For premium concert and event-grade installations, touring-grade cabinets earn their premium through headroom.

100V line distributes amplifier output through a step-up transformer, recovers at each speaker through a step-down transformer. Loses 1-2 dB per 100m of cable run — negligible. Default for distributed BGM in restaurants, retail and large public spaces where many small speakers are wired across long distances from a central amp. Low-impedance (8 ohm typical) delivers higher peak SPL with lower distortion and full bandwidth. Default for live events, premium worship, theatre and serious AV where SPL and fidelity matter more than wire cost.

When the source material extends below the main cabinet's low-frequency rolloff. Most install line-array boxes roll off around 60-80 Hz; touring cabinets sometimes to 50 Hz. Kick drums, bass guitar, electronic music, film LFE channels and orchestral percussion all extend to 30-45 Hz — outside main-cabinet bandwidth. Pairing 2-6 subwoofers (depending on room size) with mains is standard for live amplified music. For speech-priority installations (worship sermons, conferences) subs are often unnecessary; the main cabinet's natural rolloff matches voice fundamentals.

Per-seat SPL prediction with real-room reflections, array splay/taper modelling and processor configuration. Soundvision (L-Acoustics), ArrayCalc (d&b), K-array proprietary, EASE Focus (generic) — all output per-seat SPL maps, frequency-response per seat, sub-array steering and amplifier deployment plans. Use the calculator on this page for first-order scoping; specify the brand's prediction software output as a project deliverable from your integrator. The two tools are sequential, not redundant.

The public database now carries 525 selectable models across 32 professional-audio, commercial-audio and architectural speaker brands. Kasper Sound and other domestic / international brands are added only after datasheet collection, because a record we cannot cite is a record the calculator should not compute from. The planner's own "Request a model" panel — the one inside the calculator frame, not the contact form — is the intake: it asks for the brand, the model string and nothing mandatory beyond that, and additions land in cited batches.

The 100 V / 70 V transformer tap list. Of the 70 publicly selectable constant-voltage records, 4 publish their taps and 66 do not — and a tap is a transformer SETTING, not a power rating, so nothing else in the record substitutes for the missing list. The load a 100 V line presents to its amplifier is the sum of the taps the commissioning engineer actually selects, which means a record without them cannot have that load computed, and reading a top tap out of a published power figure is exactly the inference that previously overstated three records in this catalogue. That is why the planner suppresses the applied-watts readout on those records rather than printing a number it cannot stand behind. If you are sending us a constant-voltage model through the request panel, the datasheet page carrying the tap table is the single most useful thing you can attach — more useful than the headline power figure, which is the field it is most often confused with.