Listening on period instuments can be revelatory. The first movement of Beethoven's Waldstein sonata, which is murky on a modern piano, is comparatively clearer on the fortepiano. The fortepiano has much faster and more pronounced decay (in the Attack-Decay-Sustain-Release ADSR formulation) and weaker bass, but that punchiness works well for the Waldstein as it makes it easier to hear the rhythm.

https://www.youtube.com/watch?v=3fhmm_hfZAo

As a complement to period instruments, I found that Switched-On Bach by Wendy Carlos also made me listen to Bach in a new light. Physical low-register instruments do not speak all that clearly — not even today, and not in Bach's time either. Compare a string bass with an electric bass — or even more starkly, a synthesizer bass!

The bass register in Switched-On Bach has much cleaner, more identifiable pitch than Bach would have heard from a period ensemble playing one of the Brandenburg Concerti. But is one actually more "true" to Bach than the other?

My feeling is that what Bach heard in his head were closer to a synthesizer version than a baroque chamber ensemble version. Because even though a good composer strives to write for a medium and compensate for the strengths and weaknesses of actual instruments, the essence of Bach is counterpoint and harmony, not orchestration.