Can you really hear those 64' tones?

[Krummhorn]

The Liverpool instrument uses the 32' Double Open Bass along with the 32' Violone (wired to play at 21-2/3' when the 64' Resultant Bass stop has been drawn, thus creating the effect of a 64' stop.

Here's a definition from the Encyclopedia of Organ Stops that shed more light on what defined a Resultant tone.

Further, a quote from Dolmetsch Online Music Dictionary:
"a note produced under certain circumstances when two notes are played simultaneously, one of two types, either difference or differential tones (a note whose frequency is the difference between the frequencies of the two generating tones) or summation or summational tones (a note whose frequency is the sum of the frequencies of the two generating tones)."