Applications of SoundCheck for Headset Testing Include:
- Analog wired headsets
- USB headsets
- Bluetooth headsets
- Stereo or Mono
Industry Standard Headset Tests
- Frequency response
- Self-noise and signal-to-noise
- Max SPL
- Loudness Ratings
- Send sensitivity in a diffuse field
- Directional characteristics (polar plot)
- TIA 810/920
Features and Benefits of SoundCheck for Headset Testing
SoundCheck features a variety of test signals and analysis methods for measuring the frequency response of both the receiver (speaker) and microphone path in a headset. A stepped sine sweep is ideal for simple analog headsets with minimal audio signal processing, and simple digital headsets with stable latency. More advanced methods are necessary to test complex headsets or headset systems, because they do not react in a normal way to stepped sine signals. One example is a headset with substantial signal processing, such as a compressor, expander, etc. Other examples are digital devices, like Bluetooth headsets, that are prone to dropouts and latency shifts. These more complex headsets necessitate the use of broadband stimuli like noise, speech, or simulated speech (i.e. ITU-T P.50). SoundCheck features the ability to use any WAV file as a stimulus, giving you the flexibility to choose your own source signal. These stimuli can even be corrected by a calibrated equalization curve when using a mouth simulator as the output source.
SoundCheck can communicate with any device that appears in the list of Windows audio devices. This means that testing a Bluetooth or USB headset is as easy as connecting it to a PC and selecting it from a list in SoundCheck. No external digital interface is required! A standard Listen-recommended soundcard is used for sending signals to a mouth simulator and receiving the signals from an ear simulator. All of the audio to and from the headset is handled directly in the SoundCheck test sequence.
Measuring distortion is a key part of any headset testing. Typically the receive transducer is tested for Total Harmonic Distortion and possibly Rub & Buzz. SoundCheck’s HarmonicTrak algorithm accomplishes both of these, as well as generating a frequency response, from a single acquired waveform. The user has the option to select exactly which harmonics are analyzed, and a plot of distortion versus frequency is created. A multitone stimulus can be used to test devices that do not work well with sine waves (e.g. Bluetooth headsets). The multitone analysis can also output a non-coherent distortion plot. While this measurement is not identical to THD, it can be an effective metric for analyzing a device’s real-world performance. Another option is to use pulsed-noise distortion measurements, recently described in IEEE 269.
Conformance to Standards
Some customers may have the desire or requirement to test their products according to an international standard. Listen offers two suites of test sequences for performing these measurements on headsets: TIA 810-B and TIA 920. Purchasing these sequence bundles saves a significant amount of test development time and is a great enhancement for an R&D system.
Typical Headset Test System Configuration