sae ieoponeul sassneunde soriga isanghage deullyeo.

새 is the short prenoun form meaning new when it comes directly before a noun.

• 새 이어폰 = new earphones
• 새 책 = a new book
• 새 집 = a new house

새로운 can also mean new, but it often sounds a little more descriptive or formal, and it is based on the adjective 새롭다 (to be new/novel).

So in everyday speech, 새 이어폰 is the most natural way to say new earphones.

Because the two parts of the sentence are doing different jobs.

• 새 이어폰을 샀는데 = I bought new earphones, but/as for that...
  • 이어폰을 uses 을, the object marker, because earphones are what was bought.
• 소리가 이상하게 들려 = the sound sounds strange
  • 소리가 uses 가, the subject marker, because sound is what is being described as strange.

So the sentence structure is roughly:

• [I bought new earphones]
• [the sound sounds strange]

This is very natural in Korean. One clause has one subject/object setup, and the next clause has another.

Here, -는데 connects the first clause to the second and gives a sense like:

• I bought new earphones, but...
• I bought new earphones, and...
• I bought new earphones, but the thing is...

In this sentence, it often feels like a mild contrast or disappointment:

• I bought new earphones, but the sound is weird.

So 샀는데 is not just a plain bought and. It sets up the next part as something noteworthy, unexpected, or contrasting.

A useful way to think of it:

• -고 = simple connection: and
• -는데 = connection with background, contrast, or lead-in

Because 이상하게 is an adverb, and it modifies the verb 들려.

• 이상한 소리 = a strange sound
  Here 이상한 describes the noun 소리.
• 소리가 이상하게 들려 = the sound sounds strangely / sounds weird
  Here 이상하게 describes how it sounds.

So:

• 이상한 = adjective form used before nouns
• 이상하게 = adverb form used before verbs

That is why 이상하게 들려 is correct here.

It is related, but the verb here is actually 들리다, not 듣다.

• 듣다 = to listen / to hear intentionally
• 들리다 = to be heard / to sound

So:

• 소리를 들어 = listen to the sound
• 소리가 들려 = the sound is heard / sounds

In this sentence, the speaker is not actively listening in the sense of 듣다. They are describing how the sound comes across, so 들리다 is the natural verb.

A very common pattern is:

• 좋게 들리다 = to sound good
• 이상하게 들리다 = to sound strange
• 작게 들리다 = to sound quiet

In this sentence, it is best understood as sounds.

들리다 can sometimes mean:

• to be audible / be heard
• to sound

But with expressions like 이상하게 들리다, 좋게 들리다, 이상하게, 이상하게 들려, it usually means to sound.

So here:

• 소리가 이상하게 들려 = the sound sounds strange

That is more natural than understanding it as I can hear the sound strangely.

Korean often leaves out subjects when they are obvious from context.

In this sentence, it is easy to understand that the speaker means something like:

• (내가) 새 이어폰을 샀는데...
• (I) bought new earphones, but...

Korean does this all the time. If the speaker is clearly talking about their own experience, the subject is usually omitted.

So the full meaning is understood without saying I explicitly.

Yes. 소리가 sounds more neutral and focuses on the sound itself as the thing being noticed.

• 소리가 이상하게 들려 = the sound sounds strange
  • straightforward observation

If you said 소리는, it could feel more contrastive, like:

• As for the sound, it sounds strange
• maybe implying comparison with something else

For example:

• 디자인은 괜찮은데 소리는 이상하게 들려.
  • The design is okay, but the sound is strange.

So 가 is very natural here because the speaker is simply pointing out what is strange.

Yes, and the nuance would change slightly.

• 샀는데 = I bought them, but / and...
  • gives background or contrast
• 샀더니 = I bought them, and then / as it turned out...
  • emphasizes the result discovered afterward

So:

• 새 이어폰을 샀는데 소리가 이상하게 들려.
  • I bought new earphones, but the sound is strange.
• 새 이어폰을 샀더니 소리가 이상하게 들려.
  • I bought new earphones, and it turns out the sound is strange.

Both are possible, but -는데 feels a bit more like casual explanation or complaint, while -더니 highlights the outcome more strongly.

The spelling is 샀는데, from 사다 → 샀다 → 샀는데.

In natural pronunciation, it is commonly heard close to:

• 산는데

This happens because of sound changes in fast, natural Korean speech.

So even though it is written 샀는데, you may hear something that sounds more like 산는데. That is normal.

It strongly suggests that something is wrong, but it does not explicitly state the cause.

소리가 이상하게 들려 means the sound seems weird/strange. That could mean:

• the earphones are defective
• the connection is bad
• the sound settings are wrong
• the audio source itself is strange

So the sentence expresses the speaker’s impression, not a confirmed diagnosis. It sounds like a complaint or concern: I bought new earphones, but they sound weird.