I was wondering if we could use mind's ear just way mind's eye is used. Is it ok to use it as a valid phrase?
yes it is valid, there is reference of this word in
Reference Example :
It is surely a valid phrase but it is not considered a set phrase in English.
The "mind's eye" is a well established set phrase in English meaning the imagination, with an emphasis on the visual, imagining a scene.
The phrase the ",mind's ear", based on analogy with the mid's eye, is much less common and only would be used in the much rarer circumstance of imagining something heard. It should be used only in situations that are purely aural, and then the phrase would still sound strange and unfamiliar, stylistically it would stand out as very metaphorical.
There is a word Audiation, coined by music education researcher Edwin Gordon in 1975 (http://en.wikipedia.org/wiki/Audiation)
Audiate is to hearing as visualise is to seeing.
And as we visualise with the eye of the mind, we may surely audiate with the ear of the mind.
Of course it will initially sound uncomfortable, as it is not commonly used. And when you hear something for the first time you may be suspicious: "Why have I not heard this before? There must be something wrong with this!"
But there is nothing wrong with it. People should audiate more with their mind's ear.
It has been found that practising audiation can hone musical skills, for example singing odd bars of a melody while audiating even bars. This is a standard ear-training exercise.
EDIT: I am curious as to whether there is any existing extension of the construct to other senses, for example to conjure in one's mind a sense of smell or taste, or even a generic sensation.
"imagine" and "visualise" are both rooted in the visual sense.