In addition to the acoustic insulation panels, you may also want to check your windows and doors to make sure they're keeping sounds out as much as possible. Double or triple glazing can make a big difference to the amount of noise that gets inside and having heavy external doors can also help.
Question: Right after takeoff, it often seems that the pilot slows down and the plane drops somewhat. Why is that? I have noticed that it is pretty consistent. Answer: The sensation of slowing down is really one of slowing the rate of acceleration; this is due to reducing the thrust after takeoff to the climb setting.
Generally speaking, flying at higher altitudes means higher airspeed because of less drag. Of course, the type of aircraft you are flying will come into play as you work with flying at different altitudes, as will the amount of weight you are carrying. But realities of aerodynamics and physics remain the same.
Meanwhile, one single tone means that a passenger is trying to get help from a flight attendant. This is the sound you'll hear if you press the “call” button at your seat. Three tones mean an emergency, Cimato says.
3 dings means something or nothing at all. It depends on the airline's procedure. At one airline, it means there is such an urgent emergency that the captain has no time to discuss it with the flight attendants. At another airline it means the flight attendants are now safe to get up and walk around the plane.