"the wavelength of a sound wave would change as it experiences a change in medium. However, this does not mean that the pitch, which is related to the frequency, would change. In fact, it shouldn't change. In general, there will reflections of the wave upon a change of medium. Therefore, the 'loudness' which is related to the amplitude of the wave, will also change.
"To answer your main question, you can hear a difference if you change the transmitting medium."
That is a very odd description. Wavelength and frequency are proportional. Wavelength is defined by the speed of light divided by the frequency. I am not certain how they can say wavelength changes but pitch does not. Pitch is not a term used in my profession, however I believe it is solely based on frequency. If frequency changes, then so does the wavelength and vice versa.
I'm breaking the rust & corrosion off a lot of things I learned in college many decades back, so I'm with you there.
Here's what I found on a quick search of "does frequency of sound change with medium". From "https://physics.stackexchange.com/questions/313779/besides-the-speed-of-sound-what-else-changes-when-the-transmitting-medium-chang":
"the wavelength of a sound wave would change as it experiences a change in medium. However, this does not mean that the pitch, which is related to the frequency, would change. In fact, it shouldn't change. In general, there will reflections of the wave upon a change of medium. Therefore, the 'loudness' which is related to the amplitude of the wave, will also change.
"To answer your main question, you can hear a difference if you change the transmitting medium."
That is a very odd description. Wavelength and frequency are proportional. Wavelength is defined by the speed of light divided by the frequency. I am not certain how they can say wavelength changes but pitch does not. Pitch is not a term used in my profession, however I believe it is solely based on frequency. If frequency changes, then so does the wavelength and vice versa.