This has to do with placement of the transducer under the saddle and is a very easy adjustment. When woods get dry they can shift slightly causing the saddle (white bone piece) to become misaligned with the electronic transducer underneath meaning you will have one string with more volume than another. Now your heavier strings will always carry more volume than the thinner strings, so if you're lacking volume on the thinner strings this would need to be adjusted using the dials on your electronics control box. In adjusting the saddle over the transducer the first thing we do is make sure humidity levels are minimally 60%. If not humidify your guitar as shown in our video "buzzing and rattling strings" as this alone can move things back into position and cause the saddle to to back into alignment with the transducer underneath. If you've humidified your guitar and you're still having an issue the second thing we do is tap down hard on the saddle to make sure the saddle is seated securely and tightly over the transducer underneath. It may sound a bit crude but in working on these guitars over 3 generations it's sometimes the simple things that get the best results. If you're still not hearing any sound differences after tapping on the saddle at that point we recommend loosening the strings (about 25 turns) and making sure the saddle is seated in proper position over the transducer. If they're out of alignment and not touching fully you may hear some sound loss. Mr. Zager goes over this in more detail on this video: https://youtu.be/CnbYhbtZTtE If you're still having an issue most any shop can adjust this in 10 minutes which is much less costly and time consuming and risky than shipping your guitar across the country.