Krishna’s name is a noun, a transcendent noun.
Nouns are words, sounds that carry meaning. When you hear a word in a language you don’t understand – it is only sound. But as you repeatedly listen with curiosity and intelligence the meaning becomes clear. When you understand a language, hearing the sound of a word immediately invokes your awareness of the meanings and implications of the word.
There is no real meaning to “hearing the sound” of Krishna’s name without the sound of that name causing you to become aware of Krishna.
When we are “newborn” we don’t understand much in the sound of words (Krishna’s names). So it behooves us to listen carefully to the sound, with curiousity and intelligence (i.e. do our best to learn as much as we can about the person being named, mainly by reading Śrīmad Bhāgavatam). When we are “a few years old” we begin to understand words. When we hear the names of Krishna, the sound will invoke in us awareness of the person being named – naturally, that is simply what nouns do.
However, the names of Krishna are transcendental nouns. Therefore as we become “full grown” in hearing and chanting these nouns – hearing the name of Krishna will invoke in our awareness direct cognition of the named (Krishna). At this stage we begin to experience in the name more than what we read about Krishna – more directly, more personally. The name is becoming pure and showing its inherent nature of non-duality from the named.
The effort to “simply hear” the name, without “remembering Krishna” as a result of hearing it is rather like an infant trying to remain an infant and never learn how to use words.