You don’t mention which Fishman pickup you are using. Is it the SBT-HP? If so, that’s a single transducer. On a large harp sound board a single transducer will have a stronger response to the strings close to the pickup.
I had a K&K Sound Big Twin installed on my L&H 85CG at the factory. With dual transducers I get a very balanced sound with the pickup.
Several years ago I posted sound samples with the pickup and with a microphone. Search for “Microphones vs. Pickups” here in the forums.