Operation method

■Recording the analysis sound data

 

1. Setting of equipment

-1. DR-7100 input condition setting

The initial setting of V_RNG (voltage range) is 1 V, so please set the range as 3.16 V or 10 V for the AC output of the sound level meter (If you take margin, set the range as 10 V, if you take accuracy, set the range as 3.16 V). When the 1/2-inch microphone with constant preamplifier made by Ono Sokki is used for sound data recording, set the voltage range as 0.1 V when the expected sound pressure level is 94 dB or less, set 1V when it is 114 dB or less, and set 10 V when it is above the value as a guideline.

Keep both HPF (high-pass filter) and LPF (low-pass filter) settings as initial setting (OFF). Keep SAMP_RNG (sampling frequency) as initial setting (20 kHz, AC), and set SAMP_MOD in "FFT" or "AUDIO" setting, whichever is fine. Set the INPUT (input format) as AC when the sound level meter is used for recording, set the INPUT as CCLD when the recording sensor is microphone with constant current preamplifier is used.

 

-2. Setting of sound level meter

We recommend you to record sound data of the sound level meter to the DR-7100 without the frequency weighting.

We also recommend you to set both of sound pressure display and signal from AC output terminal without frequency weighting when the LA-1410/1440/4440 or LA-2560/3560/3570 models are used to see the range over of the sound level meter, even though the display of the sound pressure of sound level meter can be set with frequency weighting. Before recording the data by the DR-7100, measure the sound to be recorded with the sound level meter and check whether the range over error occurs or not. If the range over occurs, reset the voltage into an appropriate level range. In addition, if the sound to be recorded has no reproducibility and the level range adjustment is unabled, please use the wide range.

 

2. Recording of calibration signal data

-1. When a sound level meter is used for sound recording

Record the calibration signal before recording the sound data. For the setting of the sound level meter and the DR-7100, please refer to the "Setting of equipment" of the above. Connect the AC-OUT terminal of the sound level meter to the DR-7100.

 

●When the internal calibration signals of sound level meter is used

Press "CAL" button of the sound level meter to output the calibration signal and record it to the DR-7100. Around 10 s data length is enough for calibration. When the actual sound and calibration signal are recorded, set the sound level meter to the same level range. When the recordings are made in several level ranges, record the calibration signal each time the level range is changed. When the calibration signal is recorded, make sure to take a note of the display value of the sound level meter and the sound data which are measured with the same level range.

 

●When acoustic calibrator is used

Record the output signal of the sound level meter to the DR-7100 by using the sound calibrator to input the calibration signal from the microphone. Set the same level range to the sound level meter when the actual sound or calibration signal is recorded. When the recordings are made in several level ranges, record the calibration signal every time the level range is changed. When the calibration signal is recorded, make sure to take a note of the sound pressure value of the sound calibrator and the sound data which are measured with the same level range.

 

●When sound is recorded by the microphone with constant current preamplifier.

Record the calibration signal before recording the sound data. For the setting of the microphone and the DR-7100, please refer to the "Setting of equipment" of the above. Record the output signal to the DR-7100 by using the sound calibrator to input the calibration signal from the microphone. Make sure to take a note of the sound pressure value which is displayed in sound calibrator when the calibration signal is recorded.

 

3. Recording of sound data

Record the data to the DR-7100 by using the sound level meter or microphone with constant current preamplifier. When data is recorded to the sound level meter, please pay attention to the level range. When the sound data is recorded in some level range by the sound level meter, make sure to record the calibration signal with the same level range.

 

■ Calculation of calibration value by using the OS-2000 series

Import the calibration signal data which is recorded to the DR-7100 to the OS-2000 series basic and calculate the voltage value of sound pressure 1 Pa.

 

● Calculation of the voltage value of calibration signal

Perform the effective value calculation to the calibration signal data, and read the value at the position where the effective value becomes stable. The read value "x dB" indicates "when 1 Vrms is deemed as a reference (0 dB), the current signal size is "x dBVrms"". The voltage value without using decibel is 10 ^(x/20) Vrms when the effective value is "x dB".

 

* When the effective value calculation is performed to the calibration signal data, set the frequency weighting to "Z characteristic (FLAT)".

 

●Calculation of the Pa value of calibration signal

Calculate the value which is displayed in the sound level meter (calibration value) or sound pressure calibrator in Pa unit. The display value of sound level meter indicates "sound pressure level when sound pressure of 20×10 ^(-6) Pa is deemed as a reference". When the value which is displayed in the sound level meter (calibration value) or sound pressure calibrator is deemed as "a dB", the sound pressure becomes 10 ^((a-b)/20) Pa <b is the sound pressure level when sound pressure is 1 Pa = 20 log (1/(20×10^(-6))) = 93.9794>.

 

● Calculation of V/EU (What V is for 1 Pa)

Divide the voltage value that is calculated in above by Pa value. V / Pa = 10 ^{(( x-a+93.9794)/20)}

 

Calculation example

During the calibration by using internal signals of sound level meter, when the display value of the sound level meter is 104.0 dB and effective value of OS-2000 series calibration signal is -9.031 dBVrms;

Sound pressure is 3.162 Pa, effective value voltage is 0.3548 Vrms and calibration value (V/Pa) is 0.1115 V/Pa.

 

 

■ Changing of file information by using the OS-2000 series

Sound pressure and sound pressure level can be read by setting the calibration value into the sound data which is recorded in the OS-2000 series.

 

●Changing of calibration value

Open the "Channel setting" in "data compilations". Change the "Signal type" of sound data to "sound pressure level" (because the reference value which the sound pressure level is calculated 20×10 ^(-6) Pa ). Input the calibration value which you have calculated in above to "1/EU" of "Channel setting" (if comply with previous example; 0.1122). After changing the settings, the sound data can be read by Pa unit. Also, calculation of the effective value enables reading the value as sound pressure level (dB).

 

*Open the "Channel setting" of calibration signal data and input the calculated calibration value to "1/EU" of "signal type" and change the "signal type" to "sound pressure level". After changing the settings, operate effective value calculation to the sound data. If the sound pressure level (dB) becomes same value as the recorded calibration value, you can confirm that the calculation is correct.