Jag känner mig lugn när jag lyssnar på musik.

Both can work, but they mean slightly different things.

• Jag är lugn = I am calm
  This describes your state more directly.
• Jag känner mig lugn = I feel calm
  This focuses on your personal feeling or inner experience.

So känner mig lugn is a very natural way to say that music makes you feel calm.

Mig means myself / me and is the object form of jag.

In känner mig lugn, the verb känna sig is a common Swedish pattern meaning to feel in the sense of how someone feels emotionally or physically.

Examples:

• Jag känner mig trött. = I feel tired.
• Hon känner sig glad. = She feels happy.

So here:

• jag = I
• känner mig = feel
• lugn = calm

Because lugn agrees with the person being described, and here it refers to jag.

When an adjective describes a person after verbs like vara, känna sig, bli, etc., Swedish usually uses the common gender/base form when talking about en-words or a person in general.

• Jag känner mig lugn. = I feel calm.
• Hon är lugn. = She is calm.

You would use lugnt with a neuter noun or in some adverb-like uses:

• Det är lugnt. = It is calm / No problem / It’s okay.

So in this sentence, lugn is the correct form.

Because Swedish normally requires a subject in each clause.

The sentence has two parts:

1. Jag känner mig lugn
2. när jag lyssnar på musik

In English, we also usually repeat the subject:

• I feel calm when I listen to music.

So Swedish needs jag again in the second clause.

Here, när means when.

• Jag känner mig lugn när jag lyssnar på musik.
  = I feel calm when I listen to music.

You would not normally use då in the same way here.

• när introduces a time clause: when
• då often means then or is used in some other structures

So for this sentence, när is the right word.

In Swedish, the verb lyssna usually takes på before the thing you are listening to.

• lyssna på musik = listen to music
• lyssna på radio = listen to the radio
• lyssna på mig = listen to me

This is just the normal verb pattern in Swedish. Even though English says listen to, Swedish says lyssna på.

So you should learn lyssna på as a unit.

Because Swedish often uses nouns without an article when talking about something in a general sense.

• Jag lyssnar på musik. = I listen to music.
• Hon gillar kaffe. = She likes coffee.

Here musik means music in general, not a specific piece or a specific kind already identified.

If you were talking about specific music, you might say something else, for example:

• Jag lyssnar på den här musiken. = I’m listening to this music.

Yes. Swedish present tense often covers both:

• I listen
• I am listening

So jag lyssnar can mean either, depending on context.

In this sentence:

• när jag lyssnar på musik can be understood as when I listen to music or when I’m listening to music

Swedish does not usually need a special progressive form like English am listening.

The word order is normal for Swedish.

Main clause:

• Jag känner mig lugn

Time clause:

• när jag lyssnar på musik

So the full sentence is:

• Jag känner mig lugn när jag lyssnar på musik.

If you move the time clause to the front, Swedish changes the word order in the main clause:

• När jag lyssnar på musik känner jag mig lugn.

Notice that after the fronted clause, the verb comes before the subject:

• känner jag not
• jag känner

This is an important Swedish word order rule.

Yes, lugn can relate to both ideas, but the exact meaning depends on context.

For a person:

• lugn usually means calm

For a situation or environment:

• lugnt can mean calm, quiet, peaceful, or even no problem in some contexts

In your sentence, because it describes how I feel, lugn clearly means calm.

In standard Swedish, känner is pronounced roughly like SHEN-ner, not with a hard English k sound.

Why? Because k before front vowels like ä, e, i, y, ö is often pronounced like a sh/ch sound in Swedish.

So:

• känner ≈ SHEN-ner
• jag is often pronounced like yah in everyday speech
• lugn has a long vowel and a soft final sound that may be tricky for English speakers

An approximate full pronunciation is:

• Yah SHEN-ner may loogn nehr yah LISS-nar paw moo-SEEK

That is only approximate, but it can help as a starting point.

Yes, you could, but it changes the nuance a little.

• Jag känner mig lugn när jag lyssnar på musik.
  = I feel calm when I listen to music.
• Jag blir lugn när jag lyssnar på musik.
  = I become calm when I listen to music.

känner mig focuses on the feeling itself.
blir focuses more on the change into that state.

Both are natural, but känner mig lugn is closer to I feel calm.

Yes. This sentence pattern is very useful:

Jag känner mig + adjective + när jag + verb + ...

Examples:

• Jag känner mig glad när jag träffar mina vänner.
  = I feel happy when I meet my friends.
• Jag känner mig trött när jag jobbar sent.
  = I feel tired when I work late.
• Jag känner mig trygg när jag är hemma.
  = I feel safe when I am at home.

And with lyssna på:

• Jag lyssnar på poddar. = I listen to podcasts.
• Jag lyssnar på radio. = I listen to the radio.
• Jag lyssnar på min favoritlåt. = I listen to my favorite song.

So this sentence gives you a very practical grammar pattern to reuse.