El repertorio cambia después de la prueba de sonido.

Spanish often uses the definite article more than English does. In this sentence, el repertorio refers to a specific repertoire or set of pieces that both speaker and listener can identify, so el sounds natural.

Using just repertorio by itself would usually sound incomplete here.

Repertorio can mean the group of songs, pieces, or material that a performer or group is prepared to present.

Depending on context, English might say:

• repertoire
• set
• setlist
• program

If this is about a band or concert, learners often think of setlist, but Spanish may still use repertorio, which is a broader and very natural word.

Cambia is the present indicative form of cambiar for él/ella/usted.

Here it can express:

• a general fact
• a habitual action
• something that regularly happens in this context

So the sentence suggests that the repertoire changes after the soundcheck, either as a routine or as a general statement.

Other forms would change the meaning:

• cambió = changed
• cambiará = will change
• va a cambiar = is going to change

Because the subject is el repertorio, which is singular.

Even though a repertoire contains many songs, the noun itself is grammatically singular, so the verb must also be singular:

• El repertorio cambia
• not El repertorio cambian

Después de is the normal way to say after when it is followed by a noun.

Here, la prueba de sonido is a noun phrase, so Spanish uses:

• después de la prueba de sonido

If what follows is a clause with a verb, Spanish usually uses después de que:

• después de que termina la prueba de sonido

So the choice depends on what comes next: a noun or a full clause.

Spanish usually includes articles in places where English might not. La prueba de sonido refers to the specific soundcheck relevant to the event, so the article is natural.

English often says after soundcheck, but Spanish commonly says:

• después de la prueba de sonido

That does not sound overly formal; it is just standard Spanish structure.

Yes. Prueba de sonido is a very common and widely understood term in Latin America.

You may also hear borrowed or less standard expressions in some places, but prueba de sonido is the safest and most natural general option.

In Spanish, a noun can modify another noun with de, and the second noun is often left in the singular when it expresses a category or function.

So prueba de sonido means a test related to sound in general, not a test of multiple separate sounds as countable items.

This is similar to other common patterns:

• mesa de madera
• tarjeta de crédito
• sala de espera

Not with the same meaning.

Cambiar can be used in different ways:

• El repertorio cambia = the repertoire changes
• Cambian el repertorio = they change the repertoire

Se cambia would sound passive-like or impersonal in many contexts, and it would not be the most natural choice here if you simply mean that the repertoire changes.

So El repertorio cambia is the best version for this sentence.

Yes. That word order is grammatically correct.

Spanish allows more flexibility in word order than English. Putting Después de la prueba de sonido first can give more emphasis to the time sequence:

• El repertorio cambia después de la prueba de sonido.
• Después de la prueba de sonido, cambia el repertorio.

Both are correct, though the original order is more neutral.

Yes, mostly.

In this sentence:

• el repertorio is masculine
• la prueba is feminine
• el sonido is masculine

Some endings can help, but they are not perfect rules. For example, nouns ending in -orio like repertorio are often masculine, while many nouns ending in -a like prueba are feminine. Still, the best habit is to learn nouns together with their articles:

• el repertorio
• la prueba
• el sonido

The accent mark in después shows where the stress goes: des-PUÉS.

A rough pronunciation guide:

• repertorio → reh-pehr-TOH-ryoh
• cambia → KAHM-byah
• después → dehs-PWES
• prueba → PRWEH-bah
• sonido → soh-NEE-doh

The accent mark is important because without it, the stress pattern would not be written correctly.

By itself, it most naturally sounds like a general or habitual statement: this is what happens after the soundcheck.

Spanish present tense often covers both:

• general truths
• habits
• scheduled or expected actions

If you wanted to make it clearly about one past event, you would normally change the tense, for example:

• El repertorio cambió después de la prueba de sonido.

So the original sentence most naturally suggests a regular pattern or a present-time statement.