[linux-audio-user] Announcing the "KarmaPod"

[Brad Fuller]

David O'Toole wrote:
> I don't have one of those nifty decibel meters, so I can't give
> distance + decibels for the machine. I consider it very quiet, when
> you factor in all the drives etc. It's obviously better when the fans
> have just been cleaned. 
>
> Is there a way to get accurate decibel readings using my Delta 1010
> and Pd? I'd do it and post the results. . . 
>   
Looks like you are in NY (right?) so you could take a trip to the local
Radio Shack and get their cheap SPL meter.

To get an unscientific, ballpark reading you could get/borrow a mic -
with as flat as a response as you can find. The mic and the environment
tested within would be your biggest variables. Depending on what mic is
used, and the environment you test in, you'll get different results.
I'm sure you don't have an anechoic room to test in,   :-(   but just
some basic readings at a distance of 1/2 meter, 1 meter, 3 meters from
the loudest producing area would be helpful. Take the case to the
quietest (of external sounds), and most carpeted (to reduce reflections)
that you can find.

I'm sure there's gotta be a pink noise generator in pd and a module that
can plot the resultant frequency spectrum from the mic. You might also
indicate the mic used -- maybe the published freq response and polar
response of the mic can be used to help interpret the result.

Not scientific in the least, but a reasonable approach for a ballpark
reading.