Portable nasometry unit

The Nasality Microphone is a low cost, handheld, nasometry unit that detects nasality during speech production. It uses a lightweight acoustic separator that is fitted with highly directional nasal and oral microphones. The portable design is quick and easy to assemble, and comes complete with a slimline carry case.

How nasometry works

The Nasality Microphone uses a special lightweight acoustic separator that is positioned above the upper lip. The acoustic separator is fitted with independent, highly directional, nasal and oral microphones.

Nasality is represented by a numerical value called nasalance, which is defined as the percentage of the total acoustic energy that is nasal:

nasalance equation

Nasalance, which is calculated for voiced sounds only, can be viewed in real-time for visual feedback, or recorded for off-line analysis.

Nasometry System

Software options

NasalanceViewer

NasalanceViewer is easy-to-use Windows software that provides an ideal introduction to nasometry. Features include:

  • Provides real-time visual feedback of nasalance
  • Provides off-line objective analysis of nasalance
  • Provides auditory playback of speech production
  • Waveform display with adjustable target cursor
  • Skywriter game with adjustable target cloud
  • Simple to use interface
  • Windows 10, 8, 7 and Vista compatible
  • 10 user license

NasalanceViewer 3D

In addition to providing numerical displays of nasalance and nasal-oral speech, NasalanceViewer 3D uses state-of-the-art computer animation and 3D modelling techniques to approximate velopharyngeal closure and nasal-oral airflow.

The animated 3D model consists of the lips, teeth, tongue, lower jaw, hard palate, soft palate and uvula. The transparency of these articulators can be adjusted to reveal hidden structures, and the model can be rotated 360°. Airflow clearly illustrates the difference between nasal, oral, voiced and voiceless sounds.

NasalanceViewer 3D • nasal airflow (soft palate lowered)

Nasal airflow (soft palate lowered)

NasalanceViewer 3D • oral airflow (soft palate raised)

Oral airflow (soft palate raised)

NasalanceViewer 3D • voiced airflow (intermittent flow)

Voiced airflow (intermittent flow)

NasalanceViewer 3D • voiceless airflow (continuous flow)

Voiceless airflow (continuous flow)

Additional features include:

  • Real-time visual feedback of nasalance
  • Off-line objective analysis of nasalance
  • Auditory playback of speech production
  • Photorealistic and stylised views
  • File format compatible with icSpeech Professional Edition
  • Windows 10 64-bit and 8 64-bit compatible

icSpeech Professional Edition

The Nasality Microphone is also compatible with the multiparameter speech visualisation and analysis package icSpeech Professional Edition, which supports a wealth of additional features.

Features include:

  • Additional displays: bar, waveform, spectrogram and video
  • Additional parameters: nasalance, pitch, timing, nasal and oral acoustic energy
  • Six games with adjustable targets and rewards
  • Extensive analysis features
  • Data export facility
  • Recorder with picture and word prompting
  • Combines nasometry with EPG, airflow, voicing and video data
  • Windows 10, 8, 7 and Vista compatible

The importance of acoustic separation in nasometry

For accurate results, it is important that there is a good seal between the face, just above the upper lip, and the acoustic separator. This prevents oral sounds being detected by the nasal microphone and vice versa. To ensure a good seal, the acoustic separator incorporates large and small facial contours. Simply rotate the nasal and oral microphones so they point to the side that best fits the contours of the face. The acoustic separator is also fitted with highly directional noise cancelling microphones, which further improve the acoustic separation.

Nasometry acoustic separator

Microphone matching

It is also important that the nasal and oral microphones are acoustically matched. During the manufacturing process, both the sensitivity and frequency response of the nasal and oral microphones are individually matched. This eliminates the need for the user to calibrate the Nasality Microphone. The microphone matching characteristics are supplied with each device.

Cleaning

The Nasality Microphone is easy to dismantle and clean. The foam windshields covering the nasal and oral microphones can be removed and replaced, or washed in warm soapy water. The individual microphones, acoustic separator and handle can be removed and thoroughly cleaned with disposable disinfection wipes.

Nasometry cleaning

Replacement windshields

Slip-on foam windshields, made from durable, high quality open-cell controlled-density acoustic foam. Designed to protect the microphone elements from contamination, and to reduce noise from plosive sounds.

Nasometry replacement windshields

System specification

Microphones

Left channel Nasal speech
Right channel Oral speech
Type Electret condenser
Directionality Uni-directional
Frequency response (band-pass filter disabled) 100 - 15,000Hz
Frequency response (band-pass filter enabled) 350 - 650Hz
Sensitivity -40dB at 1kHz (0dB = 1V/Pa)
Output impedance 2.2k ohm
Power supply 1.5V - 10V

USB audio adaptor

Microphone input 2 channel stereo
Sample rates 48kHz, 44.1kHz. 16kHz and 8kHz
Resolution 16bit
THD -90dB
Frequency response 20 - 20,000 Hz
Input range 0 - 1.25 Vrms
Dynamic range 96dB
Record gain range -6 - 33dB
Supply voltage 4.5 - 5.5 VDC via USB
Total power consumption 33 mA

System requirements

Supported operating systems Windows 10, 8, 7 or Vista
Supported computers Desktop, laptop, tablet
Connectivity USB 1.0, 2.0, 3.0
Power USB bus powered

Get quote

The nasometry package includes:

  • Nasality Microphone
  • Carry case
  • Four microphone windshields
  • User manual
  • 12 months guarantee
  • NasalanceViewer software (optional)
  • NasalanceViewer software 3D (optional)
  • icSpeech Professional Edition software (optional)
Portable Nasometry System