Maybe > dozen. Depends on the specs. Like how Proliant DL are lounder than other rackmounts, Irwindales active hsf oscillate with changing loads, etc. A mixed cluster might do that with 4-6. Anyway, what a nice recorder you have, real nice. You did a great job.
I used this recording as part of a sound piece played within a sculptural cave-like installation called the "Cryptic Lagoon", by Andrew Kerr, exhibited at Utrophia Project Space in Deptford, South London. The recording was played fairly straight and also granulated to the point of sounding like an ape playing free jazz on a child's gamelan set.