Key features RC4 Dimmers

RC4 wireless key featureVARIABLE PWM FREQUENCY

RC4 Wireless provides the widest range of PWM frequencies available on the market: from 77Hz up to 40kHz.

Whether you need flicker-free operation for super-slow-motion video, or the smoothest LED dimming ever seen by the human eye, or interference-free audio from nearby microphones and pickups, RC4 has the PWM frequencies that are right for you.


77 Hz – 615 Hz – 1250 Hz – 5 kHz – 10 kHz – 20 kHz – 40 kHz


Using common PWM dimming near electrified musical instruments and microphones can result in audible interference. This is because 77Hz, 615Hz, 5kHz, and 10kHz are all audible frequencies, and audio circuitry can be exceptionally sensitive to electromagnetic interference. The solution for this is 20kHz and 40kHz PWM. These very high modulation frequencies deliver lower resolution, not high enough to completely eliminate “steppiness” at the bottom of the ISL curve when dimming LEDs.  Nonetheless, this trade-off is entirely acceptable when clean, clear, crisp audio is paramount.


The selected frequency will be used whenever an ISL curve is assigned using either RC4 Commander software or RC4 OneTouch™, or RDM (remote device management).

If you will routinely be using your RC4 Series 3 dimmer with video, leave the PWM frequency at 5kHz. If you are always lighting instruments and microphones, leave it at 20kHz. Be sure to switch back to 615Hz in live performance situations to deliver the best appearance for human observers.

  • The PWM frequency setting is stored and remembered forever until you change it or restore default settings.
  • Factory default for RC4Magic devices is 615Hz (ideal for human eyes).

  • Factory default for LumenDim devices is 5kHz (ideal for most motion-picture applications).

Lower frequencies are more efficient and deliver higher power handling with less heat. Higher frequencies avoid banding and other visual artifacts when captured with video equipment. 615Hz provides the smoothest dimming when perceived by the human eye.

When capturing video, do a camera test and select the lowest frequency that is free of visible artifacts (like banding or flicker). Higher PWM frequencies are required for higher frame-rates. You can try this at home with an iPhone or other high-resolution digital video camera — capture video and experiment with different PWM frequencies. You can see the difference higher frequencies make.

Set PWM Frequency to Eliminate Video Artifacts

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