Despite both of us having our doors closed, if you made any sound above a conversational speaking voice, you could totally hear.
However, we had a room with a door to the next room over (for families that want double rooms). But for us, it was constant loud noise, the smell of smoke (despite good ventilation), and the sight of a whole bunch of people looking sad and at the end of their ropes mashing the slot machine buttons over and over praying for a miracle. If casinos are your thing, this will sound ridiculous. I didn't even want the players card! I HAD to get it! Ugh. Then back to the hotel desk line to get our room. Well, the casino desk was very confused by our get-away package and it took close to 20-30 minutes to work everything out. But in order to stay at the hotel, I HAD to wait in line at hotel desk, only to be told to walk over to some other desk on the hotel floor, to get some 'players card' or something FIRST, and then come back to hotel desk. So the casino part did not appeal to us in any way. I must start by saying that this was used for our anniversary, and neither of us are gamblers. So this was our first time to ever visit. We won at a charity auction a 'night's stay get-away at the Hard Rock!'.
