The term that describes the ability to "hear" colors or perceive colors as sound is called "synesthesia." Synesthesia is a neurological phenomenon in which stimulation of one sensory or cognitive pathway leads to automatic, involuntary experiences in another sensory or cognitive pathway. In your case, during a manic episode, the crossing of sensory experiences may cause you to perceive colors as musical notes.
Synesthesia can take various forms, and people with this condition may experience a blending of senses in different ways. For example, some individuals might associate specific colors with particular letters or numbers, while others may associate colors with specific tastes or emotions. It is a fascinating and relatively rare phenomenon, and the experiences can vary widely from person to person.
If you notice that you experience synesthetic perceptions during manic episodes or at any other time, it may be worth discussing it with a healthcare professional or a neurologist to better understand your experiences and how they relate to your overall well-being.