Originally Posted by Dbuudo07
Thanks for the info. So you're saying Herb, someone I'm learning about for the first time, is buying units, calibrating them and selling them? I will move up to a higher quality mic in the future that can measure below 10hz.
As I stated earlier, Herb is Cross-Spectrum Labs
. He also goes by "anechoic" here, HTGuide, TechTalk, and HTS...probably other places as well.
To summarize the most popular options again.
DIY a Panasonic capsule based mic: Needs calibration if you want absolute response numbers. Otherwise, like an RS SPL meter, it can still be used to show before/after changes simply by analyzing relative changes. Accuracy for subwoofer measurements down to 20Hz is probably pretty good without a cal, but the capsules are subject to some manufacturing variability and the user's ability to build/provide a suitable preamp will also be a factor.
ECM8000: Available from any number of vendors. Doesn't include a calibration file. Generic cal files are available on the internet, but of questionable value since a number of folks have compiled enough data to show a decent amount of unit to unit variation.
EMM-6: P-E includes a 20-20kHz on axis (0°) cal file unique to each mic, S/N traceable. Herb, and likely other cal services, will provide more data points (higher resolution) across that range. After doing hundreds of these mics, Herb has recommended the P-E cal file as good enough if you only want to measure on axis from 20-20kHz. IIRC, the biggest variation is usually in the 12-15kHz area, where Herb's extra resolution will provide more accuracy and a smoother curve.
Purchase a calibrated ECM8000/EMM-6: Herb/Cross-Spectrum will sell you either and has options for different levels of calibration. I linked you to his EMM-6 page in an earlier post. Penn suggested there are other retailers selling calibrated ECM8000s, but I'm not aware of who he's referring to. Herb's cheapest cal option is on axis from 5-25Khz. He also has options for 45°/90° axis, polar response, and sensitivity. Full boat cal for an EMM-6 is $99 to a US address; the ECM8000 runs about $10 more. He will ship internationally.
Buy the mic of your choice from the vendor of your choice and send it out for calibration. Cross-Spectrum and Kim Giardin (sp?) are probably the most well known to the DIY community. Google should turn up others.