My AMPROBE SM-CAL1 Sound Meter Calibrator just arrived and I thought I would figure out how to setup an accurate SPL meter in Smaart 7. Fortunately, Rational Acoustic’s “Calvert Dayton” has already provided instruction on how to go through the process via a post on the Rational Acoustics forum. Calverts response is #7.
Re: SPL –measurement does not what it should
Instructions as follows:
1. Open the Amplitude Calibration dialog window by clicking CalibrateSound Level Options button in the dialog (Options > SPL/LEQ…).
2. Select the audio device and input channel that you want to calibrate.
3. Turn on your calibrator and wait a moment for the average to stabilize — say 10-15 seconds for a microphone calibration using an SLC, maybe 20 to be on the safe side. 20 seconds would be enough time to build from -138.5 dB (all 0’s in a 24-bit integer) to 0 dBFS (all 1’s), given a 0 dBFS reference tone.
4. Click the Capture button.
5. Type your nominal reference level (e.g., 94, 104 or 114 dB) in the Calibrated Level field — when performing a microphone calibration in the field you generally want to use the highest output level that your sound level calibrator offers.
6. Hit the Enter key to recalc the Calibration Offset.
7. Click the Apply button.
8. If you want to calibrate additional inputs, go back to step 2 and loop through again. Otherwise click the Done button to exit the dialog.
Here is another website that described the method: