How is this nominal phrase meant

Question

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The sentence in question (line 5): 井上さんは神戸で客が歌うのに合わせて演奏をするしごとをしていた。 My attempt at translation: "Mr. Inoue had a job in Kobe where he did musical performances matching what the customers sang."

客が歌うのに is of special interest here. As I translated, I think that の is like こと here and it literally nominalizes the verbal phrase 客が歌う into " 'the customer sing' thing". However, I might be wrong, and here is why I think so. I could also imagine the phrase being 歌う客に合わせて...: "...job where he did musical perfomances matching the singing customer." Ultimately, both phrases mean the same, but they are still different from a grammatical perspective. Since I don't feel very sure about my interpretation, I wanted to ask for confirmation.

In case my first interpretation should be correct, would the second construction I thought up be grammatical?

Answer 1

I think you're correct.

客が歌うのに合わせて＝客が歌うこと　に　合わせて　＝　synchronizing the act/thing of customer's singing. This is a reasonable interpretation, I think.

However, if you think の＝こと＝声＝voice, it becomes easier to translate: Synchronizing costumer's singing voice. This is an interpretation in which the の is a pronoun like "it" or "one." And the "it/one" could mean their "voice."

Besides, your version, 歌う客に合わせて演奏していた, is perfectly fine and grammatical. And I agree with your point. This sentence has a different syntax grammatically, although the meaning is the same.

井上さんは神戸で客が歌うのに合わせて演奏をするしごとをしていた。

Mr. Inoue had a job to play the musical instrument synchronizing customer's singing voice.

Answer 2

You were close, but の here is a pure nominalizer, and 客が歌うの refers to the action of singing itself by the customers, not what they sing (i.e., the name of the song, lyrics...).

So 客が歌うのに合わせて演奏をする literally means "to do musical performances in time to customers' singing," and the 歌う客に合わせて演奏をする literally means "to do musical performances in time to singing customers." Both are grammatical, and I think they roughly mean the same thing in this context.