All these responses are suggestive of mild synesthesia, where one sense spills over into experiences in another. In strong synesthesia, for example, some people will experience distinct colors for each word or digit they encounter. Here we have largely visual metaphors for aural experiences. Yet in synesthesia the visual experiences aren’t merely metaphorical. They are inseparable, in experience, from the reality.
There are some neuroscience researchers who suggest we’re all, at least mildly, synesthetic. But the thing about synesthetes is that where one person may always experience the number 9 as blue, to another it may be red. The experience is at the level of something objective; the reality is nonetheless a subjective one. Still, the number 9 is real, and different from other numbers. So the subjective perception of coloration is nonetheless accurate in indicating an objective difference in the underlying reality. It’s not just psychological. What comes across as a metaphoric expression points to something real, despite the problem this presents in creating a common language for the quite real and fundamentally accurate personal experiences of difference.