What would we see if we had glasses that converted sound waves into light waves, assuming our brain became accustomed to them?
• If the glasses converted sound into light at proportional wavelengths or frequencies then you might be rather disappointed by the experience of "watching" music. Your ears can hear sound across nine or 10 octaves depending on your age. An octave is the interval between two notes where the frequency of the higher note is double that of the other: a piano typically covers more than seven octaves from lowest to highest key.
Your eyes on the other hand are sensitive to light with a frequency of between 400 and 790 terahertz, which is not even one octave. You would therefore be disappointed to find you could see less than a single octave of sound, maybe around middle C. The low notes of a piece of music would ...
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