Bluetooth Headset Measurement
A sequence to test the send and receive performance of a stereo Bluetooth headset with a built-in microphone using a mixture of analog and digital channels.
This sequence tests the send and receive performance of a stereo Bluetooth headset with a built-in microphone using a mixture of analog and digital channels. The left and right earphones are measured simultaneously with a stepped sweep from 20kHz to 20 Hz using two Bluetooth profiles: A2DP and HFP. The mic is measured with a stepped sweep from 8kHz to 100Hz using the HFP profile.
A short 1kHz tone is pre-pended to the test stimulus which serves as a reference tone for resampling and frequency shift operations. Post-processing resampling and frequency shift precisely synchronizes the stimulus and response waveforms prior to analysis. In this case, the HarmonicTrak algorithm is used for frequency and THD analysis. A2DP frequency response and THD curves are displayed on the first display, followed by A2DP & HFP curves superimposed on a subsequent display. Lastly, the Bluetooth headset’s microphone is tested with HFP and its frequency response is shown on the final display along with the previously collected data.
- SoundCheck 18.0 or later
- Head and Torso simulator – B&K 4128C HATS or similar
- Bluetooth transceiver – Portland Tool & Die BTC (part# 5814) or similar
- Audio Interface – Listen AudioConnect (part# 4050) or similar
- Microphone power supply – Listen SoundConnect 2 (part# 4025/4026) or similar
- Power amplifier – Listen SC Amp (part# 4060) or similar
Hardware Setup and Calibration
SoundCheck’s Digital In 1 and Digital Out 1 Signal Paths should be assigned a Unity Digital (AES17) sensitivity value (input sensitivity: 0.707 FS/FS, output sensitivity: 1.414 FS/FS) for device that conform to the AES17 Standard.