Setup:

The changes in setup are applied in the user profile. For further information about the user profiles, please refer to “Administration - System.”

Close the window by performing one of the following options:

Measuring Setup: Display tab

Measuring Setup: Measure tab

Under the measure tab, change settings for measuring speed and accuracy.

Resolution

Select the measurement speed (listed below). The measurement speed affects the following: frequency measurement, i/o measurement, 3-D measurement, running time, dynamic CR, and percentile analysis. It is possible to change the default settings for each of these measurements. A recommendation that compromises between accuracy and speed is <medium>.

Resolution options:

Very good = Slow, but accurate

Good

Medium

Fast

Very fast = Fast, but not as accurate

Please also refer to the Measuring Parameter tab.

Conventional measurement/FFT is running simultaneously

Conventional measurements are performed with pure tones. There are two options that occur when this setting is enabled.

1. An FFT is running for each RMS measurement with a reduction in measuring speed, which records more data.
2. Set the number of blocks between 1 and 32. A value of 2 represents good speed and an accuracy of 95%. Increase the value to increase the accuracy. The higher the value is set, the slower the measurement will become due to data processing.

Battery simulator/Voltage in Volts

Select a voltage for the battery simulator. The battery voltage should be set to 1.35 volts for a measurement (reference to voltage indicated on manufacturer’s data sheets). It is possible to select a different voltage.

Save message window

1. If enabled: a message appears following a measurement asking if the measurement should be saved or discarded. 
2. If not enabled: measurement curve is always automatically saved. 

Automatic correction of the sound field (with or without a message)

The reference microphone always measures the values of the sound field.

If enabled: deviations to the adjusted input level are calculated and added to the sound field values, which results in a continuous correction of the input sound pressure is performed. This setting is recommended for sound field measurements and not recommended for routine measurements.

Measuring speed:

Describes the time the ACAM System is idle before an RMS measurement begins. There will be an increase in the number of errors (especially with significant level change or with low frequencies), if the idle time is too short. It is recommended to use the frequency dependent setting to allow the ACAM System to remain idle longer for low frequencies and remain idle shorter for high frequencies.

Complex measurements: 2 channel FFT

The 1 and 2 channel procedure is described in detail in the section: “Background information of the test box measurement.”

1. Use the 2 channel FFT for all complex signals (CHIRP, noise, speech, ICRA).
2. Use the 1 channel FFT in the single value measurement with pure tones. When it is necessary to switch (e.g. in the single value measurement with pure tones) it is done automatically.

Input level can use the measured value from the reference microphone

Normally the selected input level is used for the reference value in the 2 channel FFT. However, the measured value from the reference microphone can also be used.

For further information, please refer to the section: “data display window.”

Real ear measurement: warble frequency and modulation factor %

Setting only applies to the real ear measurements and pure tones measurements. Default setting is a 53 Hz warble frequency and a 5% modulation. The modulation should not be set too high, because this will result in “smearing” of the results.

Enable pure tone measurements in real ear measurements

By default, pure tone measurements are disabled in real ear measurement by default. It is recommended to use complex signals like noise, CHIRP or speech for real ear measurements. Pure tone measurements in the real ear measurement are not recommended; however the user can enable this setting. When you enable this option, it is necessary to perform a calibration before using the pure tone measurement for real ear measurements.

Filter measuring signal

Select from one of three options:

<Create/change measuring series> button

Changes to the measuring series integrated in the ACAM System may be necessary (Refer to the section: “Measuring series in test box”).

The measuring series editor is an external program in the ACAM System, which allows the user to change/create measuring series. Please refer to the section: “Create and change measuring series.”

Menu entries tab:

Change the context menu of the buttons in the test box measurement and real ear measurement. Click on the item and select:

Measuring parameter tab:

Select the defaults for each setting in the measure/resolution tab. It is recommended that the default settings not be changed.

The defaults being changed are shown at the top of the screen (Figure 73). Select the recommended resolution for the corresponding measurements: frequency measurement, i/o measurement, 3-3 measurement, dynamic CR or percentile analysis.

Figure 73: Settings for resolution

Calibration tab:

Calibration settings can be configured independently for the test box and real ear measurements.

The values are not saved in the user profile, however the ACAM System is reset to the factory settings after each restart.

Input Level:

Select the input level to be used for calibration. Higher values correspond to better calibrations due to a higher signal to noise ratio. The default values for test box and real ear is 70 dB (See table below).

Measuring limit reached during calibration

If the measuring limit reached during calibration the following message will appear: Calibration Limit is reached. Click either <next> or <cancel>.

Note: measuring limit reached during calibration refers to the correction value is 0; however it should be greater than 0 to reach the necessary level.

Cancel Calibration

Calibration is canceled when a level or signal to noise ratio exceeds or falls below a selected value.

Level:

Extremely low or high levels are indicative of a defect of one or both microphones. It is not possible to continue the measurement and the measurement is canceled.

Signal to noise ratio (SNR):

Low SNR values result in an incorrect calibration. Therefore, it is recommended that to cancel the calibration. 

Default values:

If calibration is stopped, the above parameters are disregarded.

View corrections

To view the calculated corrections you may click on the button "Show marked.” The activated data are now displayed.

The data show the calibration curves and represent the accuracy and quality of the transducers used (loudspeaker and microphones).

For more information, please refer to the section: “Calibration.”

Delete Corrections

Only ACOUSTICON technicians should use this option for service maintainance.

Special calibration values can be set to zero (i.e. delete) by using <delete marked now> button. Special values can be set using the <set settings to>.

Start Calibration

Begins a calibration and returns to the screen following a calibration. 

Start System Calibration

Starts the system calibration following a warning message. Each microphone provided by ACOUSTICON will have a correction value. Therefore, ACOUSTICON guarantees that the correct sound pressure level is always indicated, despite production tolerances. An ACAM System calibration is only necessary for the first installation or when microphones are changed.

Only initiate the Start System Calibration if requested by ACOUSTICON.

IEC 118 tab

Activate a series of measurements and set the measuring conditions for the tests. Settings only affect the menu point frequency measurement/IEC 118.

Maximum Gain

If enabled, the maximum gain is measured at the level indicated. The input level should always be set at 50 dB, according to the IEC standard.

Maximum Output Sound Pressure Level

If enabled, the maximum output sound pressure level is measured at the level indicated. The input level should always be set to 90 dB according to the IEC standard.

Reference Test Gain

If enabled, the reference test gain is measured at the level indicated. For measuring the signals CHIRP or Pure Tone: select the required signal for the measurement. The input level should be set to 60 dB.

Note: Pure tone measurements are according to the IEC standard, while CHRIP measurements are not.

Harmonic Distortion

Measure the distortion values for: 250 Hz, 500 Hz, and 1000 Hz. Enable the measurement and enter the level desired to perform the measurement.

For further information, please refer to the section: “IEC 118 Measurement.”

Colors tab:

The curves displayed on the screen have various colors to help the user distinguish between them.

Click the <Change> button near the corresponding color to make changes. The standard color window of the operating system appears. After you have selected a color, click <OK> to apply the setting in the ACAM System.

For more information, please refer to section: “General information about test box measurement.”