zài ānjìng de fángjiān lǐ tīng yīnyuè hěn qīngsōng.

They work together to mark location.

• 在 = marks where something happens
• 里 = inside

So 在房间里 means in the room / inside the room. With places like 房间, 屋子, 教室, or 家, using 里 is very common because they are enclosed spaces.

Chinese often puts time and place phrases before the main action to set the scene first. So this sentence is structured like:

[In a quiet room] [listening to music] [is relaxing].

That word order is very natural in Chinese. It helps the listener know the setting before hearing the action.

的 links a modifier to a noun.

Here, 安静 describes 房间, so:

• 安静的房间 = a quiet room

In English, we just put quiet before room, but in Chinese, 的 often connects the describing word to the noun.

Because 安静 is describing a noun here, not a verb.

• 的 is used when describing a noun: 安静的房间
• 地 is used when describing how an action is done: 安静地听音乐

So:

• 安静的房间 = a quiet room
• 安静地听音乐 = listen to music quietly

Chinese does not have articles like a, an, or the.

So 房间 can mean a room, the room, or just room/rooms depending on context. In this sentence, the meaning is general, so no extra word is needed.

If you want to emphasize one room, you could say:

在一个安静的房间里听音乐很轻松。

Yes. In this sentence, 听音乐 is a verb-object phrase, but the whole action functions like a subject:

在安静的房间里听音乐 = listening to music in a quiet room

Chinese can use whole actions or verb phrases as the subject of a sentence, just like English uses gerunds such as Listening to music is relaxing.

Not always. In many adjective sentences, 很 does not strongly mean very. It often just helps the sentence sound natural.

So 很轻松 here is often understood more like:

• relaxing
• quite relaxing
• easy and comfortable
• makes you feel relaxed

If you really want a stronger very, you could use 非常:

在安静的房间里听音乐非常轻松。

Because in Chinese, adjectives can act as predicates by themselves.

So:

• 听音乐很轻松 = natural
• 听音乐是很轻松 = not natural in standard Chinese

是 is usually used to connect nouns, not normally before a simple adjective predicate. That is why 很轻松 can stand on its own after the subject phrase.

Here 轻松 means something like:

• relaxed
• relaxing
• easy
• not stressful

In this sentence, it most naturally means that the activity of listening to music in a quiet room feels relaxing or puts someone at ease.

No specific person is stated. The sentence is making a general statement:

Listening to music in a quiet room is relaxing.

Chinese often leaves out the subject when it is general or not important. If you want to make it personal, you could say:

我在安静的房间里听音乐觉得很轻松。

That makes it clear that I feel relaxed.

Yes, you can, especially in writing, if you want a slight pause:

在安静的房间里，听音乐很轻松。

Both versions are fine. The comma is optional. Without it, the sentence still sounds natural.

Sometimes, yes, but it changes the feel a little.

• 在房间里 = the most complete and common form
• 在房间 = possible in some contexts
• 房间里 = also possible when the location is already being treated as the topic

In this sentence, 在安静的房间里 is the most natural full form for a learner to use.