人：把樂器調準的那個人
最貼近核心畫面的一種：真的有一隻手在轉，而那隻手屬於一個靠耳朵吃飯的人。
noun · B2
A person whose job is to adjust a piano or an organ, tightening or loosening its parts until every note sounds at the right pitch again.
調音師
核心畫面
Think of a hand turning something slowly — a , a , a dial — and stopping the moment what comes out lands exactly on the right point: a note that matches the other notes, a station that arrives clean instead of noisy. A tuner is whoever, or whatever, does that turning or helps you find that point. Sometimes it is a person with a good ear, sometimes a small screen that shows you the distance, sometimes a part inside a machine.
tuner 可以想成一隻手在慢慢地轉。轉弦鈕、轉旋鈕、轉刻度盤，一點一點挪，直到出來的東西剛好對上。對上的可能是一個…更多收起
tuner 可以想成一隻手在慢慢地轉。轉弦鈕、轉旋鈕、轉刻度盤，一點一點挪，直到出來的東西剛好對上。對上的可能是一個音，也可能是一個電台。只要負責「把東西挪到剛剛好」的那個角色，英文就叫 tuner——有時候是一個人，有時候是一台小機器，有時候是機器裡的一個零件。From the word’s history
Wiktionary traces the word to tune (verb) + -er, with -er going back through Middle and Old English -ere to Proto-Germanic *-ārijaz. The suffix builds both people and things that do a job, which is why one word covers a piano tuner and a radio tuner.
字源上，tuner 來自 tune（動詞）加上 -er；-er 從中古英文、古英文的 -ere 一路上溯。這個字尾造得出「做事的人」，也造得出「做事的東西」，所以同一個字既能指調音師，也能指收音機裡的零件。
Wiktionary, 'tuner' (etymology 1: From tune (verb) + -er), packet source_ref kaikki:3f6f69a190036ae4:748078139
Three branches
工具：幫你找到準的位置
同一個畫面拆成兩半：一半是「看出差多少」，一半是「動手轉」。這個家族裡的 tuner 各自負責其中一半。
noun · B2
A small electronic device, or a phone app, that listens to the note you play and shows you whether it is too high or too low, so that you can bring your guitar or other instrument into tune.
調音器
零件：對準空中的訊號
轉的動作沒變，要對準的東西換了：不是一個音高，而是一個頻率。
noun · B2
The part of a radio, television, or sound system that you set to one station, so that the machine picks up that station's signal and not the others.
調諧器／選台的部分