Found a solution to an often mentioned problem when having installed a piezo type bridge plate pickup transducer. The consensus of several Internet responders who have done this is that while the sound from strings 2 through 6 is good, the high e-string is way too quiet with no real ring, sustain, etc. Some have suggested moving the transducer for that string away from a brace, Adding a 4th transducer, a not so easy job, etc.
I recently installed a JJB pickup (jjbelectronics) in a 40 year old Ventura V-14 dreadnought and a new Chinese replica of an exotically inlaid custom Martin D-45. The amplified e-string sound on each was pretty bad. I usually play with a .013 medium gauge e-string. Reasoning that my .017 B-string always sounds fine with these pickups. I went looking for a slightly heaver e-string. Didn’t even know they existed. But I reasoned, more vibrating mass in the string, more energy to the pickup. Worth a try.
Found a .014 D’Addario PL014 Custom Singles sold by Strings By Mail at https://www.stringsbymail.com Very inexpensive 79 cents each or so and worked perfectly! I suppose a .015 would be even better but I’m happy with .001 less. And the slightly heaver tension is negligible in terms of neck stress.
Both guitars amplified now sound great on all the strings! My e-string is as loud and clear as my B-string. You might give this a try if you have the same problem. The best transducers I’ve found so far for dreadnought size acoustic guitars are sold by:
JJB Electronics (Prestige 330 3-Sensor-Guitar-Pickup-Bridge-Plate) About $49
K-and-K-Sound (Pure-Mini 3-Sensor-Guitar-Pickup-Bridge-Plate) About $98