Solist rezonans üzerinde çalıştı.

It is a very common Turkish expression meaning to work on something, to focus on something, or to practice/improve something.

So here, rezonans üzerinde çalıştı means the soloist worked on resonance.
It is not meant literally as worked on top of resonance.

Because Turkish often expresses ideas with a noun + postposition/expression where English uses a direct object.

In English, you say work on resonance.
In Turkish, the natural pattern is:

X üzerinde çalışmak = to work on X

So rezonans üzerinde çalıştı is the normal way to say this idea.

Üzerinde is a form that can mean things like on it, on, over, or sometimes about, depending on context.

In this sentence, it is part of the fixed expression üzerinde çalışmak.

Historically, it comes from:

• üst = top, upper side
• plus endings that make it into a form meaning roughly on it / on that

But as a learner, the most useful thing is to remember:

• üzerinde çalışmak = to work on
• üzerinde durmak = to dwell on / emphasize
• üzerinde düşünmek = to think about

Because Turkish normally prefers verb-final word order.

A very common basic pattern is:

subject + other elements + verb

So:

• Solist = subject
• rezonans üzerinde = what the action is focused on
• çalıştı = verb

This makes the sentence sound completely natural in Turkish.

Çalıştı is in the simple past tense.

The verb stem is:

• çalış- = to work, to study, to practice

The past tense ending is:

• -dı / -di / -du / -dü or
• -tı / -ti / -tu / -tü

Here it becomes -tı, so:

• çalış- + -tı = çalıştı

It describes a completed action in the past.

This happens because of two sound rules in Turkish:

1. Vowel harmony
   The last vowel in çalış- is ı, so the past suffix must match that vowel pattern. That gives -tı or -dı, not -ti or -di.

2. Consonant harmony / devoicing
   The stem ends in ş, which is a voiceless consonant.
   After a voiceless consonant, the past ending uses t instead of d.

So:

• vowel harmony gives the ı
• final ş makes the suffix start with t

Result: çalıştı

No. Solist means soloist, so it can refer to:

• a singer
• an instrumental performer
• anyone performing solo

In this sentence, because the topic is resonance, many learners may imagine a singer, but the word itself is not limited to singers.

Yes, very often.

Turkish frequently drops subjects when they are clear from context.
So you could also say:

Rezonans üzerinde çalıştı.

That still means he/she worked on resonance, and the subject would be understood from context.

The full version with solist is used when you want to make the subject explicit.

No. Çalışmak is much broader than English work.

It can mean:

• to work
• to study
• to practice
• to make an effort
• to function, in some contexts

In a music or training context, çalışmak often means to practice or to work on improving something.

So in this sentence, it sounds like focused practice or technical work.

A few sounds may stand out:

• ç in çalıştı sounds like ch in chair
• ş in çalıştı sounds like sh in ship
• ı in çalıştı is the Turkish undotted ı. It is not the same as English ee or ih. It is a central, unrounded vowel.
• ü in üzerinde is like German ü or French u
• z in rezonans is pronounced like English z

Roughly:

• Solist → soh-leest
• rezonans → reh-zoh-nahns
• üzerinde → ü-ze-rin-de
• çalıştı → cha-lush-tuh

That last vowel in çalıştı should be the Turkish ı, not a clear English ee.

Not naturally, if you mean worked on resonance.

Çalışmak does not usually take rezonans here as a simple direct object in the way English allows. The natural Turkish expression is:

rezonans üzerinde çalışmak

If you changed the structure, you would usually need a different wording, such as a more specific verb or a longer expression. So for this exact meaning, rezonans üzerinde çalıştı is the best choice.