[Amps] Alternative cooling strategies for SB-220?

[Bill W5WVO]

I have a 6-meter-converted SB-220 equipped with the upgraded
Harbaugh cooling fan, which provides more air circulation volume
than the original Heathkit fan. It does a great job, but sounds
like a B-17 revving up for takeoff. My XYL can't stand being in
the same room with it. What solutions have any of y'all come up
with to quiet this or similar amps' cooling fans? Like for
example, are blowers generally more quiet than muffin fans? Any
other ideas?

Bill W5WVO