Is comparing the voice of one shaykh to another in terms of superiority considered backbiting (gheebah)?

Saying that one person is better than another in a certain field is not backbiting, unless the intention is to belittle or harm the person being surpassed. This is supported by the saying of the Messenger of Allah, peace and blessings be upon him, about a poor Muslim: "This one is better than an earth full of people like him," in comparison to another man.