# Stimulus — Tones, sweep, noise, Stereo ID

> Tones, sweep, noise, Stereo ID (iPhone/iPad app by BSK Apps.)

- Source: https://appshunter.io/ios/app/stimulus/id6792156906 (this page in markdown: same URL + `.md`)
- Developer: [BSK Apps](https://appshunter.io/developer/1891895847)
- Category: Music, Utilities
- Price: $4.99
- Age rating: 4+
- Requires: iOS 18.0 · 4 MB
- Languages: American English
- Released: 2026-07-23
- Data updated: 2026-09-09
- User reviews in markdown: https://appshunter.io/ios/app/stimulus/id6792156906/reviews.md

## What is Stimulus?

Stimulus is a test signal rack for live sound engineers. Four generators, a proper master section, and measurement signals that behave the way your analyzer expects. On iPhone it is a single generator with the same master section, meters, timer and export, for a signal from your pocket.

GENERATORS
- Tone: sine from 10 Hz to 22 kHz with a log slider, typed entry, and keyboard nudge (1 percent steps, 10 percent with Shift).
- Sweep: log or linear, any range in either direction, continuous or stepped in 1/3-octave dwells, one-shot or looped, with return. Hold freezes the sweep at its current frequency and lets you scrub the held tone.
- Harmonics: a fundamental with seven partials (f/4 to 5f) on faders, for exercising a system with controlled harmonic content.
- Noise: pink, red/brown, or white, continuous or in bursts, full range or band-limited to 1 octave or 1/3 octave around a centre frequency.
- Identify: GLITS (Graham's Line Identification Tone System) and the EBU Stereo ID for stereo left/right checks, positive-going polarity pops in sub, full-range, and HF widths, and a sharp click for aligning mains and delays by ear.
- Measure: pseudorandom pink noise period-matched to your analyzer's FFT frame (32K, 64K, or 128K), and a cycle-synchronised log sweep. Both loop seamlessly; export writes exactly one frame for analyzer playback.

RACK AND MASTER
- Up to four generators at once, each with level, left/right/both routing, polarity invert, mute, exclusive solo, and click-free fade in and out.
- Master level with a hard limiter at -3 dBFS, a 20 dB dim for talking over the system, master fade in and out in seconds, and an auto-stop timer.
- Stereo peak meters that follow every fade.

EXPORT
- Render any generator or the whole mix to WAV or AIFF at 44.1, 48, or 96 kHz for playback machines and test systems.

SAFETY
- New generators always start at -18 dBFS. Nothing in the app defaults loud.

One purchase covers Mac, iPad and iPhone.


## Version history (last 4 releases)

### 1.3 — 2026-09-07

Stimulus now also runs on iPhone: one generator, meters, DIM and limiter, Timer and Export.
The Guide key is gone from iPad. The guide stays on the website and in the Mac Help menu.

### 1.2 — 2026-09-06

Playback carries on when your interface changes sample rate or is unplugged.
The iPad stays awake while a signal is running.
The guide is now on iPad: a Guide key sits beside Timer and Export.
Decimals take a comma or a point.
Removing a generator keeps the editor on the one you were editing.
A band-limited noise no longer thumps when its centre frequency is moved.
Noise levels are now RMS, the way alignment signals are specified. Pink and red/brown play about 14 dB louder than before at the same setting, so check saved levels before you run them.

### 1.1 — 2026-08-19

Stereo ID: the EBU left and right identification tone, alongside GLITS. Both now draw their break pattern on screen.
Click: a sharp transient for lining up mains and delays by ear, at any rate from one every few seconds to several a second.
Noise can run in bursts instead of continuously.
One-tap keys for common frequencies, sweep durations, and levels.
Each generator strip shows where it goes: L, R, or L+R.
Buttons on iPad press in as you touch them.
Adding a generator no longer turns it on: unmute it when you want it.
Faders move on a drag, not a click.
The master timer is on the panel as Timer, with Export beside it.
Drag a generator strip to reorder the rack. Hold a strip, or right-click it, to remove it.
The polarity Pop no longer ticks when its rate or width is changed while it plays.
Harmonics faders stretch with the window: more travel, finer control.
Reset gen now resets levels and routing too.
New Session in the menu bar starts a fresh rack

### 1.0 — 2026-07-28

No release notes.

## More apps by BSK Apps

- [Go Sudoku](https://appshunter.io/ios/app/go-sudoku/id6766160748)
- [Go Solitaire](https://appshunter.io/ios/app/go-solitaire/id6766166696)
- [Go Minesweeper](https://appshunter.io/ios/app/go-minesweeper/id6766166868)
- [Go Battle Boats](https://appshunter.io/ios/app/go-battle-boats/id6769674866)

All apps by BSK Apps: https://appshunter.io/developer/1891895847

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-09-09.*