The longer tonearms "theoretically" should produce music with less distortion, due to the shallower arc. But there's other factors to be considered also, like the rigidity of the arm, the mass/compliance resonance frequency, it's tortional stability, etc. It's just as important to find a long arm that matches your cartridge as it would be on a shorter arm, otherwise a shorter arm with a better cartridge match could outplay it. There's still lots of good 9" arms that are considered reference grade for this very reason.
Bob
