I have been playing with gut strings for many years. I’ve tried various brands. Recently I’ve been playing with a whole set of Pirastro Chorda Carlos Henriquez, that I like so much. What I notice, and still do, is that the D string, especially when I play the notes from A up to the thumb position, is a little bit deaf, the sound is not clear. Ok, it’s gut, but the G string sings very well, when I play the D string, especially as I said from the note A, sings not so well. It's muddy. I noticed it with every string used: Pirastro, Gamut Pistoy, Gamut Lyon, others previously. Are all the gut D strings so or is the problem in my double bass? In the set-up, peer example?