Merging mp3 files with audacity damages sound quality

[clever smelt]

When combining sound sources with audacity, the upper 15khz part disappears completely as shown in the picture.

The second is the original sound.

I thought this was a phenomenon caused by merging mp3s, so I combined only a small amount of sound, but there was no khz loss.

Can you tell me about this? If I combine too many files, will the audio quality be lowered?

Sorry, the question may not be accurate because I don't speak English so I used a translator. ㅠㅠ

[drifting lion]

merge probably use sth else

[clever smelt]

The same thing happened with a daw called Studio One. Is there a separate way to merge mp3 files?

[drifting lion]

emm is both the input and the output mp3?

or the input is sth different

[clever smelt]

All output was extracted to wav. However, there is no damage to the sound quality in the third photo. The third photo is also a song extracted to wav.

[clever smelt]

Should I extract it in small portions?

[drifting lion]

emm

idk

probs ask another person since Im not a master at this

@raw timber could u help them ty

[clever smelt]

thx

[valid coyote]

could probably be bcuz mp3

[clever smelt]

Is there a loss in sound quality when extracting mp3 to wav? But it didn't happen the third time ㅠㅠ

[valid coyote]

mp3 has a cutoff

because compression

so you should use wav only

[clever smelt]

I also thought that mp3 was the problem, so I tried extracting only a few songs, but even when I extracted them as wav, up to 20khz came out. Is the only way to do this is to just separate the songs into small pieces and extract them?

[drifting lion]

modern problems requires modern solutions

[clever smelt]

Thank you... I'll give it a try.

This doesn't solve the problem. I'll just have to extract it little by little. Thank you to everyone who responded.

[valid coyote]

Alrighty, sad we couldn't help that much :(

[clever smelt]

Thank you for your reply.