DS-2000 Frequently Asked Questions

When using the DS-0250 throughput function to calibration the microphone with an acoustic calibration and record sound pressure data, importing it into Oscope Professional results in extremely large data values.

If we perform a sound quality evaluation using this data, the analysis result will be 130dB or higher. Since there is no definition of loudness above 130dB, the analysis cannot be performed.

■ Cause

When performing the unit calibration method for the DS-2000 on our website, the EU/V value becomes very large. Normally, the 0dB reference value for sound pressure is 20μPa, but the DS-0250 considers the 0dB reference value to be 1V. When calibration sound pressure, the 0dB reference value is also set to 1Pa, which results in a very large EU/V value.

Additional information (see our website for reference)
When the DS-2000 microphone was calibration with an acoustic calibration, the EU/V value was very high. Why is this?

The dB value for sound level is such that 0 dB corresponds to 20 μPa (Pascals). If the measured sound pressure (effective value) is P (Pa), the sound pressure level A (dBspl) is expressed by the following formula.

In the DS-2000, the input signal is voltage, so 0dB is taken as 1Vr (RMS value). The dBVr value "C" when the signal voltage is B(Vr) is

A microphone is a sensor that converts sound pressure into voltage, so if the microphone's sensitivity is K (Pa) per 1V, then the sound pressure P (Pa) for a voltage D (Vr) signal is

This is how it is found. Substituting this into equation (1)

Comparing the logarithms in equation (2) and equation (3)

For this, C(dBVr) = A(dBspl). From this, the value of V/EUSetting this option allows you to convert and display the DS-2000's C (dBVr) = P (dBspl). Also, in Oscope Professional, the EU value is represented as EU/V, so it will be the reciprocal of the set value.

■ Countermeasures

To handle the above data in terms of sound pressure (Pa) on Oscope Professional, change the signal type, multiply the EU value by a coefficient (20μ), and then set the EU value again.

As an example, we will import a sound pressure data file (Sample48K.orf) recorded with a DS-2000 into Oscope Professional. The imported data has three channels: "sound pressure," "acceleration," and "rotational speed."

You can change the channel settings in the custom items section of the plugin launcher, or click "Change Channel Settings" in the custom commands section of the Tools menu.

In the channel settings change dialog, "Channel1" will be the sound pressure signal. First, change the signal type from "Voltage" to "Sound Pressure Level". Then, copy the EU value and use a calculator to find the "EU value x 0 dB reference value" (137975.29935836792 * 0.00002). Set the resulting EU value (2.7595059871673584) again and click the "OK" button.

Check if the EU value has been changed. Drag and drop [Channel001] from the data manager into the main field and check the waveform. By default, it is set to autoscale, so the maximum and minimum values of the scale have been changed from 75000 to -75000 to 1.5 to -1.5. You can also perform sound quality evaluation analysis on the sound pressure data that has been calibration by applying a coefficient.