Pro/Forums - View Single Post - starting to think about pump sound measurement

bobkoure · 07-18-2005, 09:09 AM

This may or may not belong in this forum as I'm probably not going to end up with results that can be graphed or absolute dB readings - but this review at cooling-masters (auto-translated to English by Google) got me to thinking that comparative sound recordings might actually be useful (and are something I can produce without access to an anechoic chamber).

I'm thinking that the exclude-external-noise box idea in that review is good for a start, but that I'd, at least
- make it larger internally
- make it a bit better at excluding external noise (so probably a couple of layers of foam with "limp wall" between.
- try to reflect as little pump noise as possible (i.e. try for a "near field" recording).
- try to diffuse what sound I do reflect - try to avoid reflective sound re-enforcement.
- control vibration transmission with something like rubber band suspension (like the silent-pc folks are doing with their hard drives).

I really don't know much about microphones (but have a friend who owns/operates a recording studio and he may have answers for me) and know even less about using a PC as a recorder (which, lacking a digital recorder is probably what I'll do).
It seems to me that there at least used to be PC sound recording software that did a differential between two audio channels - the idea being that you attach a microphone to one side of a stereo audio card, leave the other with nothing, which then has whatever (electrical) noise being generated in the PC - software does the subtraction of noise from the microphone-attached side. Anyone remember something like this? What was it called?

I'm just at the "ideas" stage with this, so would really appreciate any input. BillA, if you're still lurking, please email/pm me as I know you have some "hands on" experience trying to get decent sound measurements. Feel free to call me an idiot for trying to sidestep the whole "get dB measurement without an anechoic chamber" issue

Meanwhile, I guess it's time for me to re-read the F. Alton Everest sitting in my bookcase and see what I've forgotten. If anyone's interested, I'd suggest starting out with the Master Handbook.

Credit for the original idea goes to David D. at cooling-masters.

07-18-2005, 09:09 AM	#1
bobkoure Cooling Savant Join Date: Feb 2003 Location: USA - Boston area Posts: 798	starting to think about pump sound measurement This may or may not belong in this forum as I'm probably not going to end up with results that can be graphed or absolute dB readings - but this review at cooling-masters (auto-translated to English by Google) got me to thinking that comparative sound recordings might actually be useful (and are something I can produce without access to an anechoic chamber). I'm thinking that the exclude-external-noise box idea in that review is good for a start, but that I'd, at least - make it larger internally - make it a bit better at excluding external noise (so probably a couple of layers of foam with "limp wall" between. - try to reflect as little pump noise as possible (i.e. try for a "near field" recording). - try to diffuse what sound I do reflect - try to avoid reflective sound re-enforcement. - control vibration transmission with something like rubber band suspension (like the silent-pc folks are doing with their hard drives). I really don't know much about microphones (but have a friend who owns/operates a recording studio and he may have answers for me) and know even less about using a PC as a recorder (which, lacking a digital recorder is probably what I'll do). It seems to me that there at least used to be PC sound recording software that did a differential between two audio channels - the idea being that you attach a microphone to one side of a stereo audio card, leave the other with nothing, which then has whatever (electrical) noise being generated in the PC - software does the subtraction of noise from the microphone-attached side. Anyone remember something like this? What was it called? I'm just at the "ideas" stage with this, so would really appreciate any input. BillA, if you're still lurking, please email/pm me as I know you have some "hands on" experience trying to get decent sound measurements. Feel free to call me an idiot for trying to sidestep the whole "get dB measurement without an anechoic chamber" issue Meanwhile, I guess it's time for me to re-read the F. Alton Everest sitting in my bookcase and see what I've forgotten. If anyone's interested, I'd suggest starting out with the Master Handbook. Credit for the original idea goes to David D. at cooling-masters. Last edited by bobkoure; 07-18-2005 at 09:20 AM.