USB Headset Input/Output Test Sequence
The purpose of these sequences is to test the left and right earphone outputs as well as the microphone input of a USB headset. Because SoundCheck supports both analog and digital interfaces, the headset simply plugs into a computer USB port and configures as a digital channel to be
tested like a conventional device. For output testing, a 1 kHz pilot tone alongside a 20 kHz to 100 Hz Stweep stimulus is played through the headset and captured by HATS ear simulators. For input testing, an 8 kHz to 100 Hz stimulus with a 1 kHz pilot tone is played through the HATS mouth simulator and recorded by the headset microphone. While the pilot tone is excluded from analysis, SoundCheck uses it during a frequency shift step to align the time and phase of the response signal to the stimulus. SoundCheck then analyzes the frequency response by comparing the original stimulus to the captured recording, using post-processing to calculate average sensitivity for the microphone as well as THD and L/R balance for the outputs, with all final results plotted on display.
followed by a period of silence, which is recorded through the device under test. The silence interval is analyzed using a constant 30 Hz, 4096-sample Flat Top FFT to derive the tonal noise spectrum. A dynamic tolerance mask is then generated by applying 1/1 octave smoothing to the noise curve and adding a +10 dB offset across the entire frequency range. If the unsmoothed noise spectrum peak stays below this tolerance mask, the device passes the test.
through the device under test to detect potential narrow-band impairments caused by internal electrical, fan, or drive noise. The recorded waveform is analyzed using a constant 30 Hz, 4096-sample Flat Top FFT to derive the tonal noise spectrum. A dynamic tolerance mask is then generated by applying 1/1 octave smoothing to the noise curve and adding a +10 dB offset across its entire frequency range. If the unsmoothed tonal noise spectrum peak stays below this tolerance mask, the device passes the test.
This sequence measures both conventional Total Harmonic Distortion (THD) and Normalized THD to provide a more accurate representation of a device’s nonlinear behavior. A stimulus is played through the device under test and recorded via a calibrated reference microphone and amplifier signal paths. Conventional THD compares each harmonic to the fundamental at the stimulus frequency, which can cause distortion results to be influenced by the device’s frequency response roll-off. Normalized THD instead compares each harmonic to the fundamental at its measured frequency before plotting the result at the stimulus frequency, removing the effect of linear response variations. Both methods can be displayed and analyzed within the same step, allowing direct comparison of traditional and normalized distortion results.
This sequence measures the frequency response, THD, and L/R balance of Bluetooth smart glasses speakers. After pairing the device with the BQC-4149 and placing it on a HATS, a 1 kHz pilot tone with a 20 kHz–100 Hz Stweep stimulus is played and captured through the ear simulators. The HarmonicTrak algorithm then analyzes the recording to display output performance.
This sequence measures the frequency response of Bluetooth smart glasses microphones. After pairing the device with the BQC-4149 and mounting it on a HATS, a stimulus is played through the mouth simulator and recorded by the microphone. The HarmonicTrak algorithm then analyzes the recording to display the fundamental frequency response.
This sequence calibrates a reference speaker by automatically adjusting its response against a target curve, eliminating the need to step through the calibration editor. It runs using the “Reference Mic” input and “Source Speaker.dat” output device, providing fast and consistent calibration with a single sequence run. To use different signal paths or devices, the calibration editor and sequence must be updated with matching names.
This sequence finds the test level (volts) to achieve a desired sound pressure level (dB SPL). The user enters the desired sound pressure level. 1 volt is played through the amplifier which is used to then calculate the appropriate voltage level to obtain the desired Sound pressure level. The sequence then runs a stepped sine sweep using the calculated voltage level and outputs the frequency response.
