This falls in the extremely low frequency (ELF) range which includes frequencies up to 300 Hz.

这种频率属于极低频的频率范围内，通常极低频的频带范围也在300hz以下。

youdao

"You've done really well, Kreacher," said Harry, and the elf bowed low.

“你做得很好，克利切。”哈利说。小精灵低低地鞠躬。

youdao

The important frequencies for stimulating tissue repair are all in the biologically important extremely low frequency (ELF) range.

为促进组织修复的重要频率在生物的重要极低频所有(低频)的范围。

youdao

It embarrasses me to hear people talk this way I think I'll be a low-key sort of elf.

NPR: Crumpet the Elf Reads from Santaland Diaries