Simple Sweep is a focused single-speaker measurement tool for Android. Run a 10-second log-sine sweep, get the frequency response, harmonic distortion, impulse response, step response, energy-time curve, waterfall, phase, and group delay — every result a DIY speaker builder, crossover designer, or audiophile needs from a one-shot measurement.

WHAT IT MEASURES

• Frequency response (selectable 1/12, 1/6, 1/3 and 1/1 octave smoothing)
• Harmonic distortion — THD plus H2, H3, H5 individually
• Impulse response and step response
• Energy-time curve (ETC)
• Waterfall — cumulative spectral decay (CSD)
• Unwrapped phase
• Group delay

EXPORT

FRD files compatible with VituixCAD, XSim, PCD, Speakerbench, and any industry-standard crossover design tool. Drop the file straight into your simulator.

CALIBRATED RESULTS

Upload a .cal file for your USB measurement microphone — the sensitivity header is parsed automatically and the per-unit correction is applied to the frequency response. No USB mic? Run the phone-microphone calibration wizard, which compares your phone against a USB reference mic and generates a correction curve. A manual sensitivity override is also available for users who can compare against a known SPL meter.

SOUND CHECK

A calibrated C-weighted SPL meter (dB(C) per IEC 61672) with automatic level adjustment — finds the right playback volume for a clean measurement every time. SNR-robust mode for noisy environments where absolute SPL can't be trusted.

RECOMMENDED HARDWARE

The Dayton Audio iMM-6C is a calibrated USB-C measurement microphone we recommend for accurate readings — drop in its .cal file and the per-unit correction is applied automatically. Any USB measurement microphone with a standard .cal file works.

TECHNICAL DETAIL

• Farina exponential log-sine sweep (20 Hz – 20 kHz, 10 s, 48 kHz)
• Wiener-regularized frequency-domain deconvolution with SNR-adaptive regularization
• 1 kHz acoustic sync pulse + cross-correlation to eliminate Android, USB, and Bluetooth playback-latency jitter
• Farina harmonic extraction from time-shifted echoes in the deconvolved impulse response
• C-weighting filter per IEC 61672, normalized to 0 dB at 1 kHz

Plays through the built-in speaker, 3.5 mm jack, USB DAC, or Bluetooth. Records through the phone mic or a USB audio interface using the Unprocessed input preset — AGC and noise-suppression are disabled.

BE REALISTIC ABOUT PHONE MICS

A phone microphone is not a measurement-grade instrument. For DIY tweaks, A/B speaker comparisons, and quick crossover sanity checks it works well, especially after running the phone-mic calibration wizard. For published reports, certifications, or any quantitative claim backed by numbers, plug in a proper USB measurement microphone with its .cal file.

PRIVACY

No ads. No analytics. No trackers. No network calls at all. Recordings and measurements stay on your device.

Full privacy policy: https://misca.github.io/stain_docs/PRIVACY

ONE-TIME PURCHASE

Simple Sweep is a paid app. No subscriptions, no in-app purchases, no ads — one price, all features unlocked.

WHAT THIS IS NOT

Simple Sweep is the focused single-speaker tool. It does NOT include room measurement (RT60, EDT, C80, D50, octave-band reverb, SBIR detection), multi-angle speaker profiling for directivity, or subwoofer placement tools.

If you need any of those, Stain Acoustics is the room-measurement and multi-angle edition.

Questions or bug reports? Email sales@houseofstain.com — you'll reach me, the developer, directly.