On Thu, 3 Mar 2005 23:27:30 -0600, "DanG" wrote:

(Top posted for your convenience....)

Ya won't go wrong with Quincy, but they are by no means the only good
show in town. Ingersoll and Speedaire also make good compressors.
The 3-cylinder 2-HP Speedaire I've seen in a number of installations,
plugging away at 645 RPM, produced a quiet lubba-dubba sound. I've
heard noisier home-laundry washing machines. Noisy compressors are
not acceptable in small office buildings.

I have a 5-HP two-stage IMC ripoff of the Ingersoll T-29 that is not a
bit hard to live with. A Solberg muffler on the intake helps a lot.
I wouldn't call it whisper quiet, but it's low and throaty, less
annoying than the whine of the integral fan in the 5 HP motor I use as
a phase converter.

As DanG said, no compressor is whisper quiet. A big part of having
it easy to live with is to have the noise it does make be
predominately low frequency. That means low speed, with no metallic
rattles or resonances.

You seem to want portability/mobility. That creates a tradeoff
situation because low speed means larger displacement (and weight, and
size), and freedom from rattles and resonances implies either very
good design, some massiveness or both.

My approach to your problem would be to find the lowest-speed
compressor that meets your size/weight/mobility/air-delivery needs
and then start killing rattles and resonances. First, tighten or
weld anything that rattles. Then brace things that are obviously
vibrating a lot. Then add resonance-killers (bits of solder or lead
strategically placed at nodes by trial and error) until the remaining
noise is low-freq lubba-dubba that is not offensive. You can find
nodes by feel: just run your hands over the machine. Nodes tickle
your fingertips. Just a wee bit of lead crimped or epoxied at a node
can quash a resonance very effectively.


How many times do you need to read Quincy? No compressor is
whisper quiet. Some are more tolerable than others. My Quincy is
in the same room, most of the noise comes from an add on check
valve that I installed. If you can pipe the air intake outside
and survive the consequences (heat and cold) the sound level drops
exponentially.