Weird Mouthpiece Ringing

[NickT01]

Hey y’al, I’ve been experiencing some ringing that sounds like it’s coming from my mouthpiece when I play loud around the C below the staff. I’ve tried a number of different mouthpieces and tubas and get it in the same range on all combinations. The sound I’m getting is a nice dark sound and relaxed. I’m not getting a double buzz either but rather a ringing that sounds like it’s coming from the mouthpiece. Don’t know what this could be but if anyone has ever experienced a similar problem and could help me out please let me know. Thanks!

[arpthark]

It’s probably in your bell near the mouthpiece.