In 1995 SoundCheck entered the market with the Stweep, a new proprietary test stimulus. The Stweep is an optimized stepped sine sweep that generates an integer number of cycles at each frequency step. This ensures a smooth “zero crossing” transition from step to step. It is also phase-continuous from frequency step to frequency step, which makes it sound more like a sine chirp than a stepped sine sweep. This reduces transducer ringing and decreases settling time which yields faster and more accurate measurements. Settling time is further reduced by sweeping from high to low as low frequencies have more energy than high frequencies.
The Stweep is user-configurable with different resolutions and averaging times at high and low frequencies to optimize the trade-off between stimulus duration and resolution. This customization enables a much faster sweep, cutting test time to a fraction of what it would be using the previous stepped sine method. As well as speed and accuracy, the Stweep demonstrates good noise immunity and allows many test parameters to be measured in parallel including frequency response, phase, harmonics, intermodulation with two sine waves, perceptual distortion metrics, and impedance,with a single sine sweep.
Over the past 30 years, the Stweep has become synonymous with fast, reliable end-of-line testing. It remains unmatched in its ability to combine acoustic, electrical, and perceptual measurements in a single sweep—delivering the speed, precision, and noise immunity modern production demands. A smoother continuous transition and other refinements introduced in 2017 further optimized its performance for large frequency steps and equalized measurements. While others are only now beginning to adopt similar stimuli, Listen’s Stweep continues to lead as one of the most advanced and versatile signals in the audio test engineer’s toolkit.
Traditional Stepped Sine Sweep
Stweep
