New!
Aeroview Software
The Aeroview program will produce the ‘average glottal flow
resistance’ during vowel production, Rg, and its reciprocal,
the ‘average glottal flow conductance’, Gg., using
an automated factory-optimized algorithm. Aeroview is a natural
complement to Waveview, our program for analyzing glottal airflow
waveforms by means of inverse filtering and simultaneous electroglottograph
signals. As with Waveview, we have tried to keep the user interface
simple and intuitive, to make it useful for students as well as
voice researchers.
Other measures of voice quality, such as the Sound
Pressure Level (SPL) of the measured vowel segment phonation threshold
pressure (PTP) can also be obtained.
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Shows two transducers
being used, one measures airflow, and one measures intraoral
pressure when coupled to an OPA (close-up shown on the right). |
Rg and Gg are defined:
Rg = Average Glottal Airflow / Estimated
Average Subglottal Pressure.
Gg = Estimated Subglottal Pressure / Average Glottal Airflow = 1/ Rg |
To compute Rg , the program accepts as input:
1. the airflow signal from a circumferentially vented (CV) pneumotachograph
mask and matching pressure transducer, and
2. the intraoral pressure, as measured by a catheter between the
lips connected to a pressure transducer.
To compute Rg, the subject produces a series of /p Vowel/ syllables,
as “pa pa pa pa pa”, or /b
Vowel p/ syllables, as “bap bap bap bap bap”.
The subglottal pressure during each vowel is interpolated from
the oral pressure peaks during /p/ consonants preceding and following
the vowel. This procedure was introduced in a 1973 paper
by M. Rothenberg, (A new inverse-filtering technique for deriving
the glottal air flow waveform during voicing, J
Acoustic Society of America 53, 6, 1632 - 1645, and
first applied to clinical voice evaluation by Smitheran and Hixon
(A clinical method for estimating laryngeal airway resistance during
vowel production. J. Speech and Hear. Dis. 46, (1981),
138-146).
Note: The pressure transducer used
for airflow is preferably a Glottal Enterprises PTW wideband model. If
a narrow-band PTL model is used, Rg and Gg will be recorded properly,
but the Sound Pressure Level (SPL) recorded may not be accurate
and the sound on Playback will be degraded. The transducer
for intraoral pressure may be either a PTL or PTW model.
The program is designed to work as a turnkey system with the appropriate
Glottal Enterprises masks, transducers and calibrators and the
MS-110 transducer interface electronics unit. The MS-110
can provide the needed analog to digital conversions and use a
computer’s USB input jack. However, an MS-100 system (which
does not have the A-D capacity) can be used with any third-party
multichannel A-D system that can produce a standard stereo WAV-file
format.
An important feature of the Aeroview program is that the
approximate syllable rate is automatically computed by the program
and displayed on-screen. This allows the clinician to
eliminate syllable sequences which were pronounced outside the
optimal 2.5/second to 4.0/second range. (A syllable rate significantly
higher than 4/sec may yield pressure pulses in which the subglottal
and oral pressures have not equalized, or a vowel that does not
have a quasi-steady-state segment that can be measured. (Note
that in Figure 1 the airflow only briefly attains a steady-state
before increasing, as the vocal folds abduct for the following
/p/. The syllable rate was approximately 4.1 per second. A
rate significantly slower than 2.5/sec may result in the subject
not holding the subglottal pressure constant over the syllable,
but producing a separate increase of pressure for each syllable
and a decrease between syllables. This type of pronunciation
may not allow an accurate extrapolation of subglottal pressure.)
Advantages
over Kay-Pentax PAS system
- Aeroview employs an automated version of the subglottal pressure extrapolation technique originally developed by Glottal Enterprises founder Martin Rothenberg.
- The greatly reduced speech distortion of the Glottal Enterprises CV mask means that recorded speech can be heard clearly during testing and when replayed, and results in more meaningful SPL measurements.
- The wide bandwidth of the airflow recording system means that the airflow pulse pattern during the vocalization can be seen on the display, and not just the variation in average airflow. Thus, irregular vocal fold vibration and breathy voice (incomplete vocal fold closure) can be easily identified. Using the Waveview analysis program, inverse filtering can be performed for an even better resolution of the glottal airflow waveform.
- Aeroview uses a USB input on any Windows XP computer, even a laptop. Requires no hardware installation in the computer. Easily moved between computers.
- The optional dual-chamber mask available for use with the Aeroview system can be used to stop nasal airflow leakage in a soft voice when measuring Phonation Threshold Pressure, a common source of PTP error.
- The interactive AeroviewStudent instructional CD available from Glottal Enterprises provides a thorough introduction to the operation of Aeroview and the interpretation of the results.
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AeroviewStudent Software
To make the Aeroview program available to students as an instructional
tool, as well as provide a thorough evaluation package for prospective
purchasers, we have also developed the AeroviewStudent interactive
instructional program that includes most of the
capabilities of the full version, except for the capability to
record new waveforms, plus a number of carefully selected prerecorded
waveforms of simultaneous oral airflow and intraoral pressure.
AeroviewStudent is available at low cost on a
CD that also contains a detailed 10-page Exercise Manual This
steps in this interactive manual use the prerecorded waveforms
to enable the user to learn the operation of the analysis functions
of Aeroview and the interpretation of the results for normal and
disordered voice qualities. |