low frequency
Technical term used in physics, electronics, and related fields to describe waves or signals with a low frequency.
Low-frequency sounds travel far.
This device amplifies low-frequency signals.
Means 'frequency' (the number of cycles per second); 低周波 refers specifically to low frequencies.
Compound of 低 (てい, 'low') and 周波 (しゅうは, 'frequency wave'), itself from 周 (しゅう, 'cycle') and 波 (は, 'wave').