Well, you've got two options now if you want the bass.
Option one: Bid for it and hope you don't get outbid. Even though the price is down to $1100 to start and there have been no other bids, that doesn't mean someone won't drop in a bid for $1500 at the last second. If you do this, bid what you're willing to pay, don't bid $1100 and expect to win.
Option two: Call Uncle Bob's again and see if you can make a deal before the auction ends. They lowered the price three times, so they want to sell. You might get a decent price, though maybe not the $1100 starting bid, but still a nice low-risk and reasonable price. Better do this before anyone bids if you're going to!
Whatever you do is a gamble. Maybe they'll sell it to you for $1200 outright, and you could have had it via auction for $1100. On the other hand, you could lose out or be forced to pay $1500 if someone else wants it. If you cat, you may never know what would have happened. This is so much fun!!!