1. How do you block messages?
2. what bit rate and sample rate is needed for horns?

1. to block messages press "-" (chat is still visible)
or press shift+"-" no messages visible
2. dont know

1) Press the "-" key. Located next to the backspace key on my keyboard.

2) Audacity tells me it's Mono 44100Hz, 32-bit float WAV.

acually it's 705kb/s PCM at 16bit mono 44khz

Good thing you checked then.