I had the same situation going from Lumity to Sphere. Speech in quiet was good. Solved the issue by going from M Receivers to P (Power) Receivers. Audiologist said it was something to do with the maximum headroom on the M receivers and the hearing aids were compressing? Maybe someone can help clarify but that solved the issue for me. Now the Sphere’s are superior in every way compared to Lumity. Especially battery life. When you don’t use the Sphere AI program the batteries last 2 days for me.
Jordan