Although I'm going to the Road Show this weekend at Chuck Levin's, I knew I was probably not going to get much quiet time at the event, so once I knew that the Grand Pacifics in stock, I popped in this morning when I knew it would be quiet. I Played 2 of the Grand Pacifics for the first time ever this morning - both a 317 and a 517. I was very impressed. Bigger sound than the Grand Auditoriums and it seems to be a very balanced, sweet dark sound, and the same can't be said for many other dreads I've played. My new-to-me K16 LTD was noticeably louder in the mids and highs compared to the GPs. Although the GPs have a darker sound the K16 has a more hi-fi sound.
Of those two, I liked the 317 better, but in all fairness to the 517, it was buzzing like crazy and needed a truss rod adjustment at the very least - that was very distracting.