Tenor ve bas ayrı ses gruplarında çalıştı.

In Turkish, a verb with a clearly stated third-person plural or compound subject is often left in third-person singular.

So:

• Tenor ve bas ... çalıştı = natural and common
• Tenor ve bas ... çalıştılar = also possible, but more explicitly plural

Turkish does not require plural marking on the verb as strictly as English does. Because the subject is already clear, çalıştı sounds perfectly normal.

Çalışmak has a wider range than English to work. Depending on context, it can mean:

• work
• study
• practice
• rehearse

In a musical context like this, çalıştı usually means something like:

• practiced
• rehearsed
• worked

Grammatically:

• çalış- = verb stem
• -tı = simple past tense

So çalıştı = worked / practiced / rehearsed

Ayrı means separate, apart, or distinct.

In this sentence, it describes ses gruplarında, so ayrı ses gruplarında means in separate voice groups or in different voice sections.

A useful contrast:

• ayrı = separate/apart
• farklı = different

In many contexts they overlap, but ayrı often emphasizes being physically or organizationally separated.

This is the part many learners wonder about.

ses gruplarında can be broken down as:

• ses = voice / sound
• grup = group
• -lar = plural
• -ı = the noun-compound ending on the second noun
• -nda = in/on/at, added after that possessed/compound form

So:

• ses grubu = voice group
• ses grupları = voice groups
• ses gruplarında = in the voice groups

The -ı here is not the accusative object ending. It is part of the Turkish noun-compound structure.

And the n in -nda appears because the locative ending is being attached after that -ı.

Because in Turkish noun compounds, the first noun usually stays singular and functions like a classifier.

So:

• ses grubu = voice group
• not normally sesler grubu

This is very common in Turkish:

• kitap kapağı = book cover
• okul bahçesi = school garden
• ses grubu = voice group

Even when the whole expression becomes plural, the plural usually goes on the second noun:

• ses grupları = voice groups

Yes. In Turkish musical terminology, bas is the usual form corresponding to English bass in the singing/voice sense.

So:

• tenor = tenor
• bas = bass

A native English speaker should be careful not to expect English spelling here. Turkish uses bas, written exactly the way it is pronounced in Turkish.

Because Turkish normally puts the verb at the end of the sentence.

A very common Turkish pattern is:

Subject + other information + verb

So here:

• Tenor ve bas = subject
• ayrı ses gruplarında = where/in what arrangement
• çalıştı = verb

That is very natural Turkish word order.

Turkish word order is flexible, but the verb-final pattern is the default.

Yes.

Both of these are possible:

• Tenor ve bas ayrı ses gruplarında çalıştı.
• Tenor ve bas ayrı ses gruplarında çalıştılar.

The first is very normal because Turkish often leaves the verb in third-person singular when the subject is already stated.

The second makes the plurality more explicit.

So this is not really a difference of basic meaning; it is more about style and emphasis.

Literally, ses can mean both sound and voice. But in this context, especially with tenor and bas, it refers to voice.

So ses grubu here means something like:

• voice group
• voice section
• vocal section

In choir or vocal-music contexts, that is the natural interpretation.

Here it works like an adjective, because it modifies ses gruplarında:

• ayrı ses gruplarında = in separate voice groups

But ayrı can also behave more adverbially in other sentences, for example if the idea is separately.

So in this sentence, the simplest way to understand it is as an adjective inside the phrase separate voice groups.