Magnetic (nmg) pickup is not registering on my low (5th/B) string on my Warwick Alien Thinline Deluxe 5-string acoustic bass. I think it's possible that it's defective - is it normal that the fretboard is not flush with the actual neck inside the sound chamber? (See pic) Can anyone please send pictures of the sound hole of your instrument so I can see if mine is normal? Anyone else have this problem?