RC, I've just had a thought - could the 'wierd sound' you describe, possibly be a cabinet resonance? When you play the particular note, try firmly touching different parts of the cabinet to damp any vibrations - just an idea - I had that problem on my KN6000 when I first got it

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Willum
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Willum

After silence, that which comes nearest to expressing the inexpressible is Music.
Aldous Huxley
( especially when the music is played on a KN7000....)