I find muddy sounding pickups have to do with the signal change sometimes. An easy way to test how muddy a pickup is, plug the guitar directly to a class a amp, preferably low watt. Turn the volume and tone knobs from low to high. Test it at very volume level. A good pickup will have clarity at every level. I have a Gibson SG with SD 59s and it sounds great, especially though a a cranked plexi!