Or even tens of thousands of times per second, according to an Analog Devices article: "Don’t Want to Hear It? Avoid the Audio Band with PWM LED Dimming at Freq

Or even tens of thousands of times per second, according to an Analog Devices article: "Don’t Want to Hear It? Avoid the Audio Band with PWM LED Dimming at Frequencies Above 20kHz" (https://www.analog.com/en/technical-articles/avoid-the-audio-band-with-pwm-led-dimming.html https://www.analog.com/en/technical-articles/avoid-the-audio...).