Micro ở bên nhạc trưởng.

Micro is a common Vietnamese loanword for microphone or mic.

A few useful notes:

• It is borrowed from a foreign word, so it does not look like a typical native Vietnamese word.
• You may also see micrô, especially in older writing or dictionaries.
• In everyday speech, micro is very common and natural.

Ở is used to show location.

In this sentence, it works like:

• is at
• is in
• is located at

So the structure is basically:

Micro + ở + location

That is a very common Vietnamese pattern for saying where something is.

Bên means side or beside/by the side of.

In this sentence, ở bên nhạc trưởng means the microphone is beside or by the conductor.

Related expressions:

• bên = side / by
• ở bên = be at the side of
• bên cạnh = next to / beside

So bên is doing the job of expressing proximity.

Often, yes. Many learners will hear bên cạnh more often when the meaning is clearly next to.

So these are both understandable:

• Micro ở bên nhạc trưởng.
• Micro ở bên cạnh nhạc trưởng.

The version with bên cạnh can sound a bit clearer and more explicit.
The shorter bên is still understandable, especially in context.

Nhạc trưởng means conductor.

Literally:

• nhạc = music
• trưởng = leader / chief / head

So the literal idea is something like music leader, which becomes conductor in natural English.

Vietnamese usually does not use articles like English does.

So a noun like micro can mean:

• a microphone
• the microphone

The exact meaning depends on context.

That is normal in Vietnamese. You do not need to add a separate word just to mean a or the.

Vietnamese classifiers are often used, but they are not always required.

You could say:

• Micro ở bên nhạc trưởng.
• Cái micro ở bên nhạc trưởng.

Both are possible.

A few general points:

• cái is a very common classifier for objects
• leaving the classifier out is often fine, especially in simple statements
• adding cái can make the noun feel a little more concrete or conversational

So the sentence without a classifier is not wrong.

Yes, fairly similar.

The basic order is:

subject + ở + location

So:

• Micro = the thing being talked about
• ở = is located
• bên nhạc trưởng = beside the conductor

This is quite straightforward for English speakers because the location phrase comes after the noun, much like in English.

In full, standard sentence form, ở is the normal choice.

So:

• Micro ở bên nhạc trưởng = full sentence
• Micro bên nhạc trưởng = may be heard in very casual speech, labels, or shortened style, but it sounds less complete

For learners, it is safest to keep ở in sentences like this.

This phrase can be tricky for English speakers.

A rough guide:

• nhạc starts with nh, which sounds somewhat like the ny in canyon
• nhạc has a heavy, low, stopped tone
• trưởng begins with tr, which is not exactly English ch, but English speakers often start there as an approximation
• trưởng has a dipping tone

Very rough approximation:

• nhạc ≈ nyak
• trưởng ≈ chu-uhng with a dipping voice

This is only an approximation. The tones matter a lot in real Vietnamese, so it is best to listen to native audio if possible.