for the record, I don't care all that much for the B&W 805, at least the original one. I bought a pair when they first came out and thought the mid bass was a little boomy and inarticulate, pretty much like the Grado headphones (RS 1s, think - they were $1000 and had a polarity switch on the earpiece). Since I needed them both for mixing my recordings, I sold them both for the same reason - bass was pleasant and fun, but I don't think it was accurate. I replaced the Grados with Etymotic Research. Another world!
I would expect that the 1801s would be more accurate in the bass - in fact I have looked more than once at them for near field monitors, based on reactions I have read.