World renowned conductor, harpsichordist, and baroque era musical scholar Ton Koopman is also an organist of the first class. In the above video he gives the sort of high power performance, of Johann Sebastian Bach's Fugue in G minor BWV 578, that we might imagine Bach himself giving.
J.S. Bach's first jobs were as organist in churches at Arnstadt, Muhlhausen, and Weimar, from 1703, at the age of eighteen, until 1714, and it's fair to say that the musical capabilities of the pipe organ informed and influenced most all of the music that he created throughout his life. The mighty European church pipe organs were, for hundreds of years until the advent of electronic music in the modern age, the most dynamic, harmonically rich, and just plain thunderingly loud musical instruments the world had ever known.
For the most part, however, as of the early 18th century, no one had yet tapped into all the power and polyphonic richness that the organ was capable of. One can only imagine how it must have felt to be in the pews when the young Bach climbed up into the organ loft and then totally dumbfounded everyone when he started really laying it down, slamming out huge waves of incredibly intense, majestically toneful, and rhythm heavy audio goodness. Maybe it was something like an early music rock concert.
Here's 3 1/2 hours of J.S. Bach's organ works, performed by Ton Koopman:
Fantasia & Fugue in G minor, BWV 542
Fugue in G minor, BWV 578
Canzona in D minor, BWV 588
Prelude & Fugue in B minor,
Prelude & Fugue in A minor, BWV 543
Fantasia & Fugue in C minor, BWV 562
Prelude & Fugue in C major, BWV 531
Fantasia in C major, BWV 570
Passacaglia & Fugue in C minor, BWV 582
Schubler & Leipzig Chorales