A typical cliche that is often used in Anime is that anthropomorphic cats exist. These are basically humans with cat-ears and a cat-tail (see Plausibility of the Japanese Nekomimi for a fitting picture).
I want to know how it would affect a human if he was suddenly able to hear like a cat.
I want to focus on the frequency range cats can hear. In this regard Wikipedia states that "Cats have excellent hearing and can detect an extremely broad range of frequencies. They can hear higher-pitched sounds than either dogs or humans, detecting frequencies from 55 Hz to 79,000 Hz, a range of 10.5 octaves, while humans and dogs both have ranges of about 9 octaves. Cats can hear ultrasound, which is important in hunting because many species of rodents make ultrasonic calls." Other points regarding the ears of cats, like steerable ears, can be ignored.
For this question we will assume a crazy bio-engineer in the distant future manages to operate a normal adult human, removing his human ears and instead giving him cat-ears similar to those of a Maine Coon, just bigger. This human acquires the same hearing capabilities as this type of cat. Other changes that would be necessary to make this plausible can be ignored. After the operation the human goes back to his normal life and is monitored by the crazy bio-engineer to see the results of this little test.
To make it possible to make assumptions about the environment we will stick to the present. This means that the human race will only focus on bio-engineering and not change in any other aspect. Therefore it will be normal for other people if this human disappears for some time and comes back with cat-ears, but technology, culture, etc. will (except for the acceptance of such bio-engineered humans) remain the same as today. The setting is Europe and we will imagine this human to be a middle-class white-collar worker.
This question is different from others like Plausibility of the Japanese Nekomimi because I don’t want to create a new race which is born with such capabilities and therefore accustomed to them.
I want to know what would change for a normal human if he suddenly got such capabilities and how this would affect his everyday-life.