- Charge the battery: The first time you charge the battery takes approximately 16 hours to ensure that the battery is completed charged. Plug the charger into the Charge input of the EGG and make sure the on/off switch on the EGG is in the Off position. Once the battery is fully charged, unplug the charger.
- Remove the plastic protection from the backs of the two electrodes and place them on the Velcro ribbon, separated by a distance that will put them on opposite sides of the larynx (see photo). Fasten the ribbon snugly, but not too tightly, around the neck, and insert the miniplug into the EGG (“neck”).
- Mount the head mic and connect the red miniplug to the EGG.
- Connect the output of the EGG to the input of the iMic. Use Line adjustment of the iMic initially. (If you are using a desktop computer with a line- as well as a mic-input, the EGG can connect directly with the line input of the computer.) Connect the iMic output to a USB port of the computer.
NOTE: The external soundcard (iMic) must be connected before running VoceVista . Likewise, close VoceVista before removing the soundcard from the USB port. Connecting or disconnecting the soundcard while VoceVista is running may cause the computer to crash.
- Displaying the signals in VoceVista
- Open VoceVista and select Run. A white line in the upper left display panel should extend slowly from left to right. Freeze the display by depressing the space bar.
- Press F1 for display of Waveform Envelope, Spectrogram, and Spectrum.
- Select Analysis, then Reset All Parameters (at bottom left). Leave all settings in that position except two: Audio Channel Order should be R-L, rather than L-R. THIS IS THE CORRECT SETTING OF AUDIO CHANNEL ORDER FOR THIS EGG MODEL.
- Increase Audio Segment Length to 20 ms, particularly if measuring a male voice .
- Select Project/Volume Control. A small panel with a slider to set the volume appears.
- Turn the switch on the EGG to ON, and in VoceVista select Run. Try sustaining a tone mezzo forte to forte and adjusting the slider in the small volume control panel. (If the display does not respond to the sound, go to Troubleshooting). The Waveform Envelope should fill an appreciable portion of the vertical display space, but not reach the edges, as in the following example (this particular example can be produced by clicking on Reset, Play File, and then finding Example 1 in the folder named VoceVista files)
- Freeze the display, and click on F5. Display mode F5 (Closed Quotient History, Spectrogram, Audio and EGG Waveforms) will appear (see following figure). Move the cursor in the Spectrogram (the lower left panel) to a point within the captured phonation. On the right side you should see panels displaying Audio and EGG
- Check whether the Audio and EGG waveforms 1) fill the vertical display space 2) without peak clipping, which would signify an overload. (For either of these problems, go to Signal Strength and Balance.)
- Using the left/right arrows, adjust the Delay to -0.75 ms. This is approximately the correct delay for the head-mounted microphone. (Because the left and right channels have exchanged places in this EGG, the delay is expressed as a negative quantity.)
- Locate the glottal cycle within the vertical green cursors in the EGG display. Using the up/down arrows, adjust the horizontal cursor to a point on the opening slope estimated as glottal opening: roughly, just past the point where the slope is maximally negative (arrow). The closed quotient (CQ 0.77) value is displayed below the waveform, together with the criteria level (CL 0.27), which gives the vertical position of the horizontal cursor. The following figure reflects all the above adjustments.
- Click on Analysis, and note that there are two values displayed for EGG CQ Criteria Level: History and Signal. ‘Signal’ reflects the most recent adjustment of CL in the EGG display at lower right. ‘History’ gives the setting of CL for the display of Closed Quotient History (EGG CQ, upper left). This CL, which has a default value of 35%, can only be changed after clicking on Reset.
- After some experience with a given singer and phonation type, you may want to adjust the CL of the ‘History’ to a value that will give a more accurate reading of the closed quotient.
For further information on the wealth of display possibilities in VoceVista -Pro, consult the Help for that program.
EGG Setup and Use