Halcyon and Low-pitched

Halcyon adjective - Free from storms or physical disturbance.

Low-pitched and halcyon are semantically related. In some cases you can use "Low-pitched" instead an adjective "Halcyon".

Low-pitched adjective - Used of sounds and voices; low in pitch or frequency.

Halcyon and low-pitched are semantically related. Sometimes you can use "Halcyon" instead an adjective phrase "Low-pitched".