DS-2000 Frequently Asked Questions

When performing noise analysis using the AC out terminal of a sound level meter, unit calibration is required so that the readings match the dB values of the sound level meter. Here, we will explain a simple calibration calibration please use an acoustic calibration.

■Operating Procedure

A. Operation of the sound level meter

Input the analog output signal from the sound level meter into the DS-0221 and set the sound level meter to the desired level range (in this case, select the 90 dB range).

Set the frequency weighting characteristic of the sound level meter to C-weighting.

Press the CAL button on the sound level meter. The sound level meter will output an internal calibration signal. Generally, the CAL signal from a sound level meter has a frequency of 1 kHz and outputs a signal that is -6 dB from the upper limit of the set level range, and that dB value is displayed. Here, the level range of the sound level meter is set to 90 dB, so it will display 84 dB, which is -6 dB from that value.

B. Operation of DS-0221

Click "START" to begin the measurement process.

Set the frequency range to 20 kHz and the voltage range to 1Vr. The spectrum (1 kHz) of the CAL sound level meter signal will be measured and displayed.

Unit calibration

Select [Input] → [Unit calibration] to open the Unit calibration dialog box, and check the "calibration" box.

Click the "EU/SP" tab in the dialog box to open the "EU/SP" dialog box.

-1. Position the cursor in the window over the X axis.

-2. Type "84" dB and click the "Settings" button. Overall
calibration will be performed so that the value is 84 dB.

-3. Confirm that it has changed to "X:OverAllY:84dBVr".

-4. Click "OK" to close the dialog box and confirm.

On the measurement screen, set the cursor to "Search," move it to "Overall," and confirm that it shows "X: Overall, Y: 84.0dB." calibration is now complete.

Open the "Unit calibration" dialog box by going to [Input] → [Unit calibration].

-1. The correction value "Physical value 4.358E+004EU/V" is automatically calculated and entered.
Yes, they are.

-2. Enter the unit name, such as SPL (Sound Pressure Level).

Remarks

After unit calibration, if you change the sound level meter range from 90 dB to 80 dB, you can easily correct this by setting the "Offset: -10 dB" in the "Unit calibration" dialog box in 3-iv-2. However, since you might forget that this setting remains active for subsequent measurements, it is recommended to calibration the sound level meter after changing its range.

Press the "CAL" button on the sound level meter to return to the measurement state.

Set the frequency characteristics (A, C, FLAT) and time-weighted characteristics (FAST, SLOW) of the sound level meter.
Please note that the AC output of a sound level meter generally outputs a signal that has been corrected for frequency characteristics.

We will perform noise analysis using DS-0221.

Remarks

The FFT analysis of the DS-0221 differs from the signal processing of the sound level meter; therefore, in the case of noise analysis with large variations, the displayed value of the sound level meter and the overall value of the FFT will not match.