Il volume aumenta man mano che i tenori si avvicinano.

Yes, English often drops the article where Italian keeps it.

In Italian, il volume is completely normal here. Italian uses definite articles more often than English, especially with nouns that refer to something identifiable in the situation or to a general concept being discussed.

So:

• Il volume aumenta = The volume increases / Volume increases

The Italian article does not necessarily mean extra emphasis. It is just standard grammar.

There are actually two clauses, and each has its own subject:

1. Il volume aumenta

   • subject: il volume
   • verb: aumenta

2. man mano che i tenori si avvicinano

   • subject: i tenori
   • verb: si avvicinano

So the sentence structure is basically:

[The volume increases] [as the tenors get closer].

Man mano che is a fixed expression meaning something like:

• as
• gradually as
• the more ... the more ...
• as ... progressively

In this sentence, it shows that one change happens progressively along with another:

• Il volume aumenta man mano che i tenori si avvicinano.
• The volume increases as the tenors get closer.

It is best learned as a whole expression. Even though mano literally means hand, here you should not try to translate it word by word.

Here che introduces the subordinate clause:

• man mano che i tenori si avvicinano

It works like as in English in this kind of sentence.

So:

• man mano che + clause

Examples:

• Man mano che passa il tempo... = As time passes...
• Man mano che impari... = As you learn...

Aumenta is the third person singular present indicative of aumentare.

It is singular because the subject is singular:

• il volume → singular
• therefore aumenta

Italian often uses the present tense for:

• general statements
• descriptions of what is happening
• cause-and-effect relationships
• vivid narration

So the present tense here is very natural.

Tenori is the plural of tenore.

Most commonly, tenore means tenor, especially:

• a male singer with a tenor voice
• or, depending on context, a tenor voice/part

So:

• il tenore = the tenor
• i tenori = the tenors

The article i is the masculine plural definite article used before most plural masculine nouns beginning with a consonant.

Italian often uses articles where English might omit them.

So i tenori is normal if we are talking about a specific group of tenors already known from the context, or the tenors involved in the situation.

English might say:

• the tenors
• or sometimes just tenors, depending on style

Italian is more likely to keep the article:

• i tenori

Because the verb here is avvicinarsi, which means:

• to get closer
• to come nearer
• to approach

The si is part of the verb.

Compare:

• avvicinare = to bring something closer / to move something nearer

  • Avvicinano il microfono. = They move the microphone closer.

• avvicinarsi = to get closer / to move closer oneself

  • Si avvicinano. = They get closer.

So in your sentence, the tenors themselves are moving nearer, which is why si avvicinano is used.

It is often called a reflexive or pronominal form, but in practice you should learn avvicinarsi as a verb meaning to approach / get closer.

It does not always feel literally reflexive in English. You usually would not translate it as they bring themselves closer. You simply say:

• they get closer
• they move closer
• they approach

So yes, it uses reflexive-style pronouns, but the best learning strategy is to treat avvicinarsi as its own common verb.

Not necessarily. Italian can leave that unstated if it is obvious from context.

So:

• si avvicinano can simply mean they get closer

If needed, Italian could add more detail:

• si avvicinano al microfono = they approach the microphone
• si avvicinano l'uno all'altro = they move closer to each other

In your sentence, the object or destination is not expressed because it is either obvious or unimportant.

Yes, absolutely.

That version is also very natural:

• Man mano che i tenori si avvicinano, il volume aumenta.

Italian allows this kind of reordering quite easily. The meaning stays the same. The difference is mainly one of emphasis or flow.

• Il volume aumenta man mano che i tenori si avvicinano.
  starts with the main result

• Man mano che i tenori si avvicinano, il volume aumenta.
  starts with the ongoing condition/process

Usually not if you want the same nuance.

• quando = when
• mentre = while
• man mano che = as / progressively as / the more...the more...

Man mano che specifically emphasizes gradual change happening in step with something else.

So:

• Il volume aumenta man mano che i tenori si avvicinano.
  = the increase happens progressively as they get closer

If you used mentre, it would sound more like two actions simply happening at the same time, without that strong sense of gradual correlation.

There are similar expressions.

Common alternatives include:

• mano a mano che
• via via che

These are close in meaning to man mano che.

So you may see:

• Man mano che i tenori si avvicinano...
• Mano a mano che i tenori si avvicinano...

Both are acceptable, though style and preference can vary.

For learning purposes, man mano che is a very useful standard pattern to remember.