My guess based on what I hear is that it's a pretty wide Q, but like Chef says it doesn't sound like it's centered @ 300 Hz. I think I recall that Mesa has a baked in mid Boost, and that the actual mid control is a passive cut only. I might be getting that confused with the M6 I recently sold. But if it's true, then there's a possibility that the baked in mid boost can be more complex than just being centered on a particular frequency. Mesa has a strange way of doing things like this, but the end result is glorious!