How do I calibrate Audiqueen for use with an audiometer?

Hardware Setup

Audiqueen is installed on a personal computer (PC) with a 2-channel sound card.  An audio cable connects the soundcard output (left channel only is enough) with the Audiometer's AUX input (for some machines, this is the CD1 or CD2 input).  If the audiometer is controlled by its proprietary software (suite), this is installed on the PC and a USB cable connects the PC to the audiometer.

The audiometer's AUX channel must be correctly calibrated by the manufacturer! The recommended calibration is in dB SPL.  If not sure, contact your audiometer supplier to calibrate your device.

Click here for specificities for Interacoustics audiometers...

Calibration of Audiqueen's connection

If the audiometer's AUX channel and all output lines (headphones, speakers, etc) are well calibrated by the manufacturer, only the connection between Audiqueen and the audiometer remains to be calibrated.  This is how you proceed:

For Speech Audiometry, select Audiqueen's built-in ‘Sound Delivery Module’ in the Software selector of the Format window. For all other psychoacoustic tests, this module is automatically selected.

Now you play the calibration signal and adjust the input sensitivity (or gain) of the audiometer until the VU meter shows an offset of 0 dB. Every audiometer with AUX input has a VU meter with an adjustment knob, either on the audiometer or in its software package.

In the unlikely event that you prefer not to adjust the input sensitivity (this may be the case if other external devices are connected to the same aux input), check this box and adjust the slider until the VU meter reads 0 dB offset, or click the AutoAdjust button and let Audiqueen set it for you.

Bear in mind that this attenuates A§E sounds and reduces the dynamic range of intensity. Reducing it too far reduces the usability from optimal to suboptimal, just acceptable and eventually unacceptable. This is indicated by the message (circle) at the bottom.

The system is correctly calibrated for Audiqueen if (1) the speech channel output of your audiometer is correctly calibrated and (2) the VU meter deviates to zero when playing the calibration sine. Click the ‘run verification’ button to double-check the calibration of the entire audio chain. Audiqueen will play three sounds of different intensities. With a sound level meter placed near the patient’s head, the user can measure the intensity in dB SPL and enter each value.

If Audiqueen does not confirm the correct calibration, contact the manufacturer or supplier of your audiometer for a calibration check.

Make sure your audio chain can produce at least 110 dB SPL to ensure optimal psychoacoustic testing.  If otherwise, the maximum output can be set in the Sound Delivery Parameters window.

Important information for audiometers that are NOT calibrated in dB SPL, but rather in dB HL !!!

Audiometers are either calibrated in a dB HL or dB SPL scale for speech signals.

My audiometer is calibrated in a dB SPL scale

By default, Audiqueen is designed to present speech in a dB SPL scale. Therefore, no further operations are required to make Audiqueen compatible with your audiometer device. The default intensity to which your audiometer output should be set is 85 dB SPL. For very loud or very quiet stimulation levels, Audiqueen asks you to set your audiometer to higher or lower values (like 105 or 40 dB SPL).

It is good practice to present speech signals in dB SPL. This is because Audiqueen can present all possible speech lists, each of which may have slightly different RETSPL values, depending on the language and difficulty of the test. If possible, ask the manufacturer or supplier of your audiometer to calibrate your device in dB SPL for speech signals.

My audiometer is calibrated in a dB HL scale

To make Audiqueen and its instructions to the user match the dB HL scale of your audiometer, perform the following steps:

• Go to the speech audiometry environment and click ‘New Measurement’.
• Open the ‘Speech Audiometry Settings’ by clicking on the icon in the top-left corner.
• Click the checkbox to present speech in a dB HL(!) scale and add the correct HL-to-SPL offset which is used by your audiometer device. Then press OK.
  

This will change the intensity presentation to a dB HL(!) scale in speech and speech-in-noise audiometry. Moreover, the instructions that Audiqueen gives to the user will also be adjusted to that scale.

Please note that the HL to SPL offset is only applied in the speech and speech-in-noise audiometry module.  For more information on the intensity scales of the other psychoacoustic tests in Audiqueen (HL*), see section: Decibels.

 The audiometer output settings as requested by Audiqueen can be  

monitored during testing by hovering over the blue information icon.

Execute psychoacoustic tests

All psychoacoustic tests (Speech Audiometry in quiet or noise, or A§E tests) can now be performed with Audiqueen's built-in Sound Delivery module. You should set the volume knob of the audiometer to 85 dB and Audiqueen will then control the presentation level itself.  Only at very loud (>90 dB SPL) or very quiet (<40 dB SPL) intensities will Audiqueen ask to change the volume on the audiometer.

Example of the two possible instructions Audiqueen will give to the audiologist during testing.

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