My Acoustic Guitar Sounds Tinny

Why does my acoustic guitar sound worse after I changed the strings?

I just bought a electric/acoustic guitar, it’s an off brand called Wave Garden. The strings were a bit rusty so I changed them. Originally I bought the guitar because it sounded better than my other one, but after a string changing it sounds worse. The strings sound tinny and the D string is muted when I strum. How do I fix it? Should I take it to GuitarCenter?

New strings are like shoes, they’ll need to be broken in. Continue to play on a regular basis and they’ll be broken in in under a week. Good luck.

Lady Gaga – Bad Romance – Cover [My Acoustic Version]