最さい低てい音おん部ぶ

Meanings

1

bass part; bass line

Refers to the lowest part in a musical piece, such as a bass line in a choir or instrumental arrangement. Used in musical contexts.

この曲きょくの最さい低てい音おん部ぶはとてもシンプルだ。

The bass line of this piece is very simple.

バス
バス is a more common loanword for 'bass' in music, while 最低音部 is a technical term often used in scores or formal descriptions.
低てい音おん部ぶ
低音部 means 'low-pitched part' and is broader; 最低音部 specifically means the lowest part.

Compound of 最低 (lowest) + 音部 (sound part). A straightforward technical term in music.