Getting started

Getting Started with Chirps

First launch, microphone permissions, navigating the interface, and making your first recording.

First launch

When you open Chirps for the first time, iOS will ask for microphone permission. Tap Allow to proceed. Without this permission the app cannot display a spectrogram or record audio. You can review or revoke the permission at any time in iOS Settings → Privacy & Security → Microphone.

See the Privacy page for a full explanation of what Chirps does — and does not — do with microphone access.

Choosing your input device

Chirps works with the built-in microphone on any iPhone or iPad, and with any USB microphone or audio interface connected over USB-C or Lightning.

Built-in microphone — available immediately, no configuration needed. Suitable for general audio work up to around 22 kHz.

External USB microphone or audio interface — plug it in before starting the stream. Chirps detects the device automatically and adds it to the input picker in Settings. For bat survey work, a USB ultrasonic microphone (Pettersson, Dodotronic, Audiomoth USB, or similar) connected this way extends the display up to 96 kHz or beyond depending on the device.

If you need to switch devices, stop the stream first (tap the stop button in the control bar), change the input in Settings, then start again.

The main interface

The main screen is divided into three areas:

Top bar — the strip across the top of the screen. On the left, the settings icon (three horizontal sliders) opens the Settings sheet. On the right, the folder icon opens the Recordings browser. The app name is centred.

Plot panel — the large scrolling display that fills most of the screen. In spectrogram mode, frequency runs from bottom (low) to top (high) on the vertical axis and time scrolls from right to left. In waveform mode, the same area shows amplitude over time.

Switching plot mode: Swipe the plot panel left or right to switch between Spectrogram and Waveform. Long-press the plot panel while the stream is running to reveal the waveform or spectrogram tools. Use the paintbrush to select a colour palette, and double-tap the plot to toggle the prominent grid overlay. In spectrogram view, the dB colour legend appears with that overlay.

Control bar — the row of controls below the plot (portrait) or alongside it (iPad landscape).

Control Action
Start Starts the audio stream
Stop Stops the stream, or stops an active recording early
Record Starts and stops recording while the stream is running
PT Toggle — enables Passthrough monitoring; tap again to turn Off
HET Toggle — enables Heterodyne monitoring; tap again to turn Off
Heterodyne frequency Slider: tunes the carrier frequency (active only in HET mode)
Monitor gain Slider: output volume for PT and HET modes (0.00–1.00)
Pre trigger Slider: how much buffered audio before the trigger is included
Post trigger Slider: how much audio is captured after the trigger
Ring buffer Slider: rolling buffer length, adjustable before starting the stream

Info bar — a compact strip at the bottom of the screen showing the active device name, actual sample rate, output route, and current status. Updates continuously while the stream is running.

Starting and stopping the stream

Tap the start button (the filled triangle) in the control bar. The plot begins scrolling immediately. The info bar updates with the actual sample rate negotiated with your hardware.

Tap the stop button (the square) to pause. The display freezes but your settings and any previous recordings remain untouched.

The stream does not start automatically on launch. You choose when to begin.

Your first recording

  1. Start the stream.
  2. Tap the record button (the circle with a filled dot) in the control bar. The button turns red and a timer appears.
  3. Tap the record button again to stop. Chirps closes the file after the configured post-trigger duration.

Recordings are saved to your device’s local storage in dated subfolders. If iCloud Drive is enabled, files sync automatically without any further action.

The pre-trigger buffer captures audio from before you tapped record — the default is 5 seconds. This means that if an animal vocalises just before you react, the call is still captured. Adjust the pre-trigger duration in Settings → Recording.

Reviewing recordings

Tap the Recordings button (folder icon) in the top bar to open the recordings browser. Folders appear sorted by date. Tap a folder to see its files, then tap a recording to open the Data Review interface.

Data Review is designed to feel like the live view. Swipe to switch between waveform and spectrogram. Use the Window slider to choose the visible review width, or set it to Full to inspect the whole recording. In idle review, use a two-finger horizontal pan on either plot to move the selected window through the file. Single-finger swipes still switch plot mode.

Playback is optional. Press Play to roll the plots like the live view, with matching timing, colour scaling, and recent-signal behaviour. Use PT or HET playback for listening, adjust the HET frequency when needed, use Live to return to the main view, and use List to return to the recordings list.

In full-window offline spectrogram review, single-tap the spectrogram to reveal the share button at the bottom right. Chirps exports a landscape PNG with scientific axes, ticks, grid lines, colour legend, filename, and Chirps attribution.

Orientation and layout

Chirps adapts its layout to your device’s orientation. On iPhone in landscape, the plot and controls fit the screen without hiding essential controls. A full-screen button is available in iPhone landscape mode; it hides the surrounding panels and keeps the plot nearly full-screen with a compact control row underneath. You can set orientation behaviour and landscape panel placement in Settings → Layout Settings.

Next steps