Yup. To accurately calibrate it, you need a calibrator, which is a small device that generates a 1 kHz sine wave at exactly 94 dB, and has a coupler to fit the head of your microphone. You put it up to the mic, set your preamp at a usable level, and then see what reading it comes up with. You calculate the difference between that and 94 dB, and enter that into Smaart as the calibration offset. Aside from being time consuming, you're going to pay a minimum of $300-400 (the one model that SIA sells directly costs $425).The_Guest said:
You're going to have to spend some money if you want event a somewhat accurate measurement...just go to Radioshack and plop down the cash. If you save $20 but get results that are highly skewed, then that other money was a complete and total waste. You've now got a $30 paperweight - congratulations!Has anyone picked up one of the yellow and black ones on eBay? They're a brand called "wow2buy" and the look like clones of the Radio Shack model. but under $30 including shipping (vs. $40-45 + tax for RS).
I have an analog SPL meter only because I've heard they take peak measurements better than digital meters. If the Radioshack meter has a peak-hold function then heck...I'll go out and buy one tomorrow!Also, do you prefer analog or digital?
The CheckMate meters come in several versions. The CM-130 is pretty much the RS equivalent since it has no type rating, although it's MAX function has no time limit. Personal opinion here, but the fact that the CM-130 comes with a windscreen, has a calibrator available for it and that the shape forces the mic further away from your body which helps with minimize the effect of the person taking the measurements on the results are all potential advantages over the Radio Shack meter, although the RS meter being more compact is something others may appreciate. The CM-130 is recommended for a limited frequency response of 125Hz to 8kHz, but that is not probably much of a concern if making A-weighted readings of typical sources and although it is not specified, I'd guess the Radio Shack meter has similar limitations.What about the Galaxy checkmate meters? Are they any better than the Radio Shack ones?
Most comparisons I've heard related were much closer than that, but it isn't out of the question. Both the Radio Shack meters and the CheckMate CM-130 are specified as +/-2dB accuracy, so if one meter was quite a bit older or even if one was sitting there a while and the other just came from being out in the sun or in a cold car, then a 5dB difference wouldn't be that surprising. To give Radio Shack credit, the User Manual clearly states
Of course, this statement being in the manual is one reason why it would be difficult to use the related readings for any legal purposes. Even Type 2 meters could disagree by several dB, that's why calibration is critical if you are making absolute level measurements.