Beginner's guide to PA speakers

Sound pressure level, measured in decibels (dB). The actual loudness number. Higher is louder. A typical 12-inch powered top reaches 127–131 dB max SPL; a 15-inch top reaches 133–137 dB.

SPL matters far more than watts when comparing real speakers. A 1000W speaker with 129 dB max SPL is louder than a 1500W speaker with 126 dB. Always look at SPL first, watts second.

How much electrical power the amplifier inside the speaker can push. Useful only as a rough comparison within the same brand and design. Two speakers at the same wattage from different brands can sound dramatically different.

Manufacturers also publish “peak” watts that exaggerate the number. Trust continuous (RMS) wattage and, again, the SPL spec for actual loudness comparison.

The range of pitches the speaker can produce, from lowest to highest, measured in hertz (Hz). A typical 12-inch top covers about 55 Hz to 20 kHz. Below 55 Hz you start losing the kick drum and bass note fundamentals - that is where a subwoofer comes in.

Premium 12s like the QSC K12.2 and RCF ART 912-A publish their response with a tolerance (e.g., ±3 dB). That tolerance matters - a speaker rated “55 Hz to 20 kHz” at ±10 dB is almost meaningless.

How wide the speaker throws sound horizontally and vertically. Usually written as two numbers, like “90° x 60°” or “90° conical.”

Wider coverage means more even sound across a room but less throw distance. Narrower coverage means more sound projected to the back of a room but tighter side-to-side dispersion. For most mobile DJ work, 90° horizontal coverage is the right answer.

Onboard digital signal processing. The processor built into the speaker that handles EQ, limiting, and crossover automatically. Modern powered speakers all have it.

Better DSP means the speaker protects itself from being driven too hard, applies factory-tuned EQ curves, and switches between presets (e.g., “live” vs “DJ” vs “speech”) with one button. Cheaper speakers have less refined DSP, which usually shows up as ugly limiter behavior at peaks.

The frequency at which a multi-driver speaker hands the signal between its woofer and its tweeter, or between a top and a subwoofer in a multi-speaker rig. Usually around 1.5–2.5 kHz inside a single speaker; around 80–100 Hz between tops and a sub.

You rarely have to set this yourself on powered speakers - the DSP handles it. The exception: tops + sub rigs, where you set the sub’s built-in crossover to high-pass the tops at 80–100 Hz.

How efficiently a speaker converts watts into volume, measured in dB at 1 watt, 1 meter away. Higher is more efficient. Less critical for powered speakers (the amp is built in) but useful for comparing passive cabinets.

• Two powered 12-inch tops on stands at ear height.
• One powered 18-inch sub between them (if you play bass-heavy music or 100+ guests).
• One XLR cable per speaker. One power cable per speaker. Done.

See the recommended starter rig →

Knowing the specs is useful background. Picking the right rig is faster. The quiz turns the inputs (guest count, music, indoor/outdoor, budget) into one archetype in under a minute.

Start the quiz →