That 'blurred' sound is a result of having to put a little sustain on the notes, especially when using short pedals (no heel-and-toe). No way around it, just have to try and optimize the sustain time and keep practicing your toe-only technique. What's worse? No sustain. Try a walking bass line (on pedals) with an un-modified 'B'. Not good.
chas
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"Faith means not wanting to know what is true." [Nietzsche]