Lo de improvisar a capela salió muy bien.

Here lo is not a direct object pronoun like in lo vi (I saw him/it).

In lo de + noun/infinitive/clause, Spanish uses lo de as a very common colloquial structure meaning something like:

• the thing about...
• that matter of...
• that business with...

So Lo de improvisar a capela means roughly:

• the whole thing about improvising a cappella
• that a cappella improvising thing

It often refers to something already mentioned or understood in the conversation.

Examples:

• Lo de ayer fue increíble. = What happened yesterday / that thing yesterday was incredible.
• Lo de cantar sin música salió fatal. = The thing about singing without music went terribly.

Because Spanish often uses the infinitive as a noun-like form, just like English uses -ing forms.

So:

• improvisar = improvising
• fumar es malo = smoking is bad
• viajar me encanta = I love travelling

In this sentence, improvisar a capela functions as an activity or idea.

You could also say something like:

• La improvisación a capela salió muy bien.

But lo de improvisar a capela sounds more conversational and less formal. It refers to the situation or idea, not just the abstract noun improvisación.

The verb salir does not only mean to leave or to go out. Very often, it also means:

• to turn out
• to go
• to come off

So salió muy bien means:

• it went very well
• it turned out very well
• it came off really well

This is a very common Spanish pattern:

• salir bien = to go well
• salir mal = to go badly
• me salió perfecto = it turned out perfectly for me / I pulled it off perfectly

Because salir bien/mal focuses on the result or outcome of an action, attempt, plan, or event.

• Salió muy bien = It went/turned out very well
• Estuvo muy bien = It was very good
• Fue muy bien is not correct here

So:

• Lo de improvisar a capela salió muy bien focuses on how the attempt turned out.
• La actuación estuvo muy bien would focus more on evaluating the performance itself as good.

They are close in meaning, but not identical.

Because salió is the preterite, used for a completed past event.

Here the speaker is talking about one specific occasion when the improvising happened and then ended.

• salió = it went well / turned out well on that occasion

By contrast, salía would suggest something ongoing, habitual, or backgrounded:

• Siempre salía bien. = It always used to go well.
• Al principio no salía bien, pero luego mejoró. = At first it wasn’t going well, but then it improved.

So salió is the natural choice for one finished event.

A capela means a cappella, that is, singing or performing without instrumental accompaniment.

In Spanish, a capela is a standard adapted spelling. You may also see a cappella, especially under Italian influence, but a capela is perfectly normal in Spanish.

So:

• cantar a capela = to sing a cappella
• improvisar a capela = to improvise a cappella

It is a fixed expression, which is why you do not add an article there.

Yes. The whole phrase Lo de improvisar a capela is the subject.

You can think of the structure like this:

• [Lo de improvisar a capela] = subject
• [salió muy bien] = predicate

So literally, the sentence is:

• That thing about improvising a cappella went very well.

This is one reason the singular verb salió is used: the subject is treated as one whole idea or situation.

Yes, grammatically you could, and it would be understandable:

• Improvisar a capela salió muy bien.

But lo de adds a very natural conversational nuance. It makes the phrase sound more like:

• that whole improvising-a-cappella thing
• the business of improvising a cappella

So the version with lo de is often more idiomatic when referring to a specific idea, episode, or previously mentioned situation.

Compare:

• Improvisar a capela salió muy bien. = more direct, a bit less conversational
• Lo de improvisar a capela salió muy bien. = very natural in speech when referring back to that idea/event

Yes, especially because of lo de.

The sentence is perfectly correct, but it sounds like natural spoken Spanish, the kind of thing someone might say in conversation after an event or performance.

A more formal or neutral version might be:

• La improvisación a capela salió muy bien.
• La parte improvisada a capela salió muy bien.

But the original sentence feels very idiomatic and natural in everyday speech.

It describes salió.

So the meaning is not to improvise very well in a general sense, but rather:

• the a cappella improvisation went very well
• that attempt at improvising a cappella turned out really well

If you wanted to say that someone improvises well in general, you would say something like:

• Improvisa muy bien. = He/She improvises very well.

Here, though, muy bien tells us how the event turned out.