Audio reactive effects and the RTA display

LMS can drive effects from live audio, and can display the spectrum as a real-time analyser.

Getting audio in

Choose a microphone or a system audio source in the audio settings. System audio is usually what you want for a DJ setup — it reacts to what is actually playing rather than to the room, which means it stays in time even when the room is loud.

Audio-reactive effects

Effects with an Audio reactive option respond to level or to specific bands. Turning it on reveals a gain control; if the effect barely moves, raise the gain rather than the input level, so you do not clip the capture.

Spectrum Bars and the RTA modes

Spectrum Bars has an Analyser mode:

- Visualiser — the classic look. Bars spread across the wall, tuned for
appearance rather than accuracy.
- RTA — 1/1 octave — 10 bars on ISO centres, 31.5 Hz to 16 kHz.
- RTA — 1/3 octave — 31 bars, 20 Hz to 20 kHz.

In the RTA modes the standard sets the number of bars, so Bar width no longer applies. You get a dB floor and dB top to set the scale, and a Tilt control in dB per octave.

Setting it up

Start with a dB floor around −60. If every band is lit solid, raise it — that is the noise floor. If nothing shows, lower it or check your input level.

Pink noise is the sanity check. On a 1/3-octave display pink noise should read as a flat line across the top. White noise should rise at 3 dB per octave.

🛑 It is not a measurement instrument

It looks like an RTA, and that is the problem — it is credible enough to mislead. There is no SPL calibration, no microphone correction, the operating system's capture path may be applying its own automatic gain, and the analyser is windowed and smoothed.

It shows relative spectral balance and it looks the part on a wall. Do not tune a room with it. Use a real measurement rig for that.