For the first question, kind of. In theory yes, in practice people like to move so it depends on how accurate it needs to be. It's easier to do with white nois

For the first question, kind of. In theory yes, in practice people like to move so it depends on how accurate it needs to be. It's easier to do with white noise than a sample. But ideally you would use an "impulse" (an extremely short pulse of sound) in a dead-silent room. You play the impulse and record that along with any tailing reverberation/resonance. This it typically used to "capture" the audio response of something like a room or speaker cabinet. (You can purchase Impulse Responses of Abbey Road Studios, or famous cathedrals. It can even capture a speaker response and is often used by guitarists with digital setups). But you could invert it to remove resonance. Keep in mind, even moving a millimeter will slightly change the phase of the resonances and thus the resulting response. So this would only work perfectly to remove a room response from a fixed speaker and a fixed microphone. But some mixing boards for live shows have an "anti feedback" system that works off this principle. It's not perfect, but it's good enough to prevent a microphone screech. For 2, That's an interesting thought. My guess is that it would take longer to become inaudible, and be much more "diffuse". Like being recorded in a cave or room with very complicated geometry. It's almost like how most digital reverb effects work. They tend to pass sound through multiple layers of delay (aka echo) while applying phase shifting. Sometimes they are designed to resonate, but usually they are designed so all the delay layers conflict and don't resonate too strongly in any given frequency. Part of why it resonates in such a pronounced way is the fact that it's a fixed room and almost certainly rectangular (Which you may notice many recording or mixing studios tend to avoid being a "box").