JBL Professional CBT 70J-1 — SPL & coverage

The CBT 70J-1 is rated at 131 dB SPL at 1 m, full output. SPL falls with distance under the inverse-square relationship — roughly 6 dB for every doubling of distance — which brings full-output SPL at a 12 m listener down to approximately 109 dB. Backing off to the preset's 55 % drive level lands at approximately 106 dB at that same 12 m listener: still well above the 85–90 dB range typical worship-music programme asks for, with headroom in hand.

The cabinet's 150° × 25° (H × V) nominal dispersion is what sets the ~44.8 m horizontal coverage radius the planner reports. The wide 150° horizontal spread is built for covering a broad seating plan from a single column without side-fill cabinets; the narrow 25° vertical pattern is the steerable-column signature — it keeps energy off the ceiling and side walls, controlling reflections and slap-back in a hard-surfaced worship hall. The CBT 70J-1 is passive, so it needs a matched external amplifier channel sized to the cabinet's power handling — there is no onboard amplification to budget around.

Use the planner by dragging listener distance and drive-level to watch SPL move in real time — this is how you find the point where SPL at the furthest listener drops below your target and more drive, a second cabinet, or a different model is needed. The box-count figure the planner shows is a front-coverage area estimate only; SPL adequacy at your furthest listener is a separate check and the one that actually determines whether the design works.

The planner does not model room reverberation or RT60 (a hard-floored, hard-walled worship hall can add several dB of reverberant build-up on top of the direct-field figure above), zoning across distinct seating areas (balcony, side transepts, overflow rooms usually need their own coverage pass), subwoofer pairing for low-frequency music programme, the mechanical rigging or steering-angle configuration a real column install requires, or DSP/delay tuning between multiple cabinets or zones.