I am hoping one or two of you will try something for me. Be sure that your guitar is in good standard tuning (ie A = 440). With a pristine clean sound play an A on the G string and let it ring until it fades. Listen carefully but effortlessly in a relaxed manner. Now move up a 1/2 step and play a Bb on the same string and let it ring until it fades. You may have to do this a number of times. Try it on the D string 7th and 8th frets. Try it on the B string 10 & 11th frets. I swear as the Bb fades out it puts a sour taste in mouth. It sort of makes me cringe whereas the A sounds bright and singing. What do you experience?