SPCR

As in subject: http://en.rode.com/microphones/nt1-a

Thanks in advance for sharing your thoughts/experience.

Not a great choice, mainly because any mic used for testing must be calibrated. This means matching its sensitivity to a known reference signal source, namely a mic calibrator. Such calibrators are almost all designed to fit over the head of a 1" diameter mic head. The one used here in SPCR lab is very good & cheap -- http://www.silentpcreview.com/article875-page3.html

The calibrator emits a reference 94dB 1kHz tone. The output of the mic is fed into the software, which is then adjusted & set to show 94 dB SPL. Now the measurement system is calibrated for accurate SPL. We routinely check this; it can vary a bit depending on temperature & humidity and its effects on the mic as well as the electronics. (usually less than a dB in our case, since the mic is always powered on & in the chamber, whose door is usually closed).

The mic you linked cannot be calibrated in such a manner, so it's not really useful for testing.

Rode makes another mic that's decent for testing purpose -- NT5. This is a 1/2" capsule cardioid pattern mic. The head is not a perfect fit for either 1" or 1/2" calibrator openings, but you can devise a simple adapter to fit it to the 1" opening. The cardioid pattern is not ideal for testing, but an omni capsule is available for it, NT45-O. Self-noise is 16 dBA -- not great but good enough for accuracy down to ~20 dB, which is much better than even >$1,000 SLMs.

Ask Abula about it -- he got this mic & calibrator a couple months ago. We had a long series of email exchanges that led to this.

+1 for Italian and Guatemalan SPCR test labs

MikeC wrote:Ask Abula about it -- he got this mic & calibrator a couple months ago. We had a long series of email exchanges that led to this.

Sadly i had been travelling too much lately, spending 3 sometimes 4 weeks out of home, haven't been able to test it fully. I might have more time this two weeks, but i gotta go back again on the road soon ='(. Everything is here, just need more time.

Once i finish the setup ill post my experiences, and if it works the way i think (and mike really helped a lot) ill try on the future to include noise measurements per fan.

Abula wrote:haven't been able to test it fully

Where did you find the Landtek calibrator?

Same place I found it years ago, iirc. Ebay -- http://m.ebay.ca/itm/Sound-Level-Noise- ... nav=SEARCH

Abula wrote:Once i finish the setup ill post my experiences

What about the acquisition hardware (ADC-DAC, audio interface) /software (audio anayzer or whatsoever) you sorted out?