Queen Piping, the elevated buzz in the hive when the queen is not present in a super when it has been separated from the rest of the hive. The sound the bees make when fanning across the nasonov glands to let the other bees hone in on the new hive or entrance location. The buzzing sound that the bees make when the detach their wings so they can vibrate their muscles to create heat. Never mind the sound the pissed off bee that is flying around your head makes. You can hear these different sounds with your ear, and by observing the season, temperature, the bees behavior and how you are manipulating the hive, it is easy to deduce what the sounds that they are making are for.
Infrared is available for most phone cameras and research has been done on using it to monitor the conditions in the hives. There are also heat, humidity, and weight censers available for hives with apps to connect and send the data to your computer of smart phone. In a commercial operation with a scale under a selected hive in each yard, as an operation manager you can send the workers out to the yards that need the supers based on the hives weigh gain rather than attending the yards in rotation.
Of all the monitoring hive gadgets that have been developed a hive scale to inform the beekeeper of hive weight gain of loss in my opinion is the most useful, it can let you know whether supers or syrup is needed on hives in that location.
Inferred can let you know what the cluster size is and where it is in the hive but at the time of year that this would be used, if the cluster is to small or in the wrong place, it is to cold to do any thing about it.
Enjoy all the different sounds that the bees emit, but nothing compares to opening up the hive and witnessing what is happening in the hive first hand.