My cello developed a c# resonance on the G and A strings. I have Magnacore med on the G and C, and the open G is pretty buzzy under light pressure. I also had some open seams glued after changing the strings from Helicores, which were old and dead, to the Magnacores on the bottom, Larsen A, Evah Pirazzi D. The c# resonance remained after the gluing, and a minor soundpost adjustment. Anybody have any ideas about the source if the resonance? C# is not a common wolf, right? Thanks!