Voiceover Booth

So I bought a Vo booth and I feel like it’s been a mistake. It’s very boxy or dead sounding. I’m wondering if anyone has any treatment ideas? Can I still use fiberglass panels over the foam?

So I bought a Vo booth and I feel like it’s been a mistake. It’s very boxy or dead sounding. I’m wondering if anyone has any treatment ideas? Can I still use fiberglass panels over the foam?