A looper for practicing song parts.
About this app
Rubber Ring is a tool for practicing song parts. Pick an audio file, mark a start/stop region on its waveform, and play it back in a seamless, gapless loop. It auto-detects tempo and beats to snap the loop markers to a beat grid, with full manual override.
Early-stage release — expect rough edges. Beat detection and count-in still need improvement. Feedback and bug reports welcome via Issues.
Features:
* Import-and-own library — picked files are copied into app-private storage, so loops never break when the original is moved, renamed, or deleted. * Waveform region selection with gapless looping — drag start/stop handles to mark a section; the loop boundary wraps with zero audible gap or click. * Automatic, hand-editable beat grid — a dependency-free estimator finds BPM and a downbeat, and handles snap to the beat grid. * Adjustable playback speed — slow a tricky passage down (or speed it up) without changing pitch. * Count-in — long-press Play to start after a metronome counts you in at the track's tempo. * Saved loops and practice arrangements — capture named sections per track and chain them into a sequence, each repeated as many times as you set. * Backup & restore — export your whole library (tracks and saved loops) to a file and restore it after a reinstall or on another device. * Light & dark themes, follow-playhead scrolling, and a recents list.
No ads, no trackers, no network access.
Licensed under GPL-3.0-only, by Kreuder.
What's New in v0.5
Imported from the F-Droid repository index.
- • Count-in: long-press Play to start after a metronome counts you in at the track's tempo. Set its meter and length per track under Options.
- • Options and Arrange are now bottom sheets, so they get the room they need.
- • A hint over the waveform points out that markers are moved with a long-press.
- • Waveform edge padding can be switched off in Settings.
- • Fixed: markers at the very start or end no longer collide with the back gesture.
- • Known issues: beat detection and the count-in's timing still
Version history
Jul 15, 2026 · 12.1 MB · Android API 26–36 · code 5
Imported from the F-Droid repository index.
- • Count-in: long-press Play to start after a metronome counts you in at the track's tempo. Set its meter and length per track under Options.
- • Options and Arrange are now bottom sheets, so they get the room they need.
- • A hint over the waveform points out that markers are moved with a long-press.
- • Waveform edge padding can be switched off in Settings.
- • Fixed: markers at the very start or end no longer collide with the back gesture.
- • Known issues: beat detection and the count-in's timing still
SHA-256 f7007354106e9c5265809599d0cd5aee53c0ce797e9e00fb1e62ca29daec7182
Jul 13, 2026 · 12.1 MB · Android API 26–36 · code 4
Imported from the F-Droid repository index.
- • Maintenance release so F-Droid can reproduce and publish the 0.3 features (pitch-preserving speed control and practice arrangements). No functional changes since 0.3.
SHA-256 078d43c61c45d836ef8357f30b963cb8b94b11ba2158b796298daa13068871ed
Jul 11, 2026 · 12.1 MB · Android API 26–36 · code 2
Imported from the F-Droid repository index.
- • Light, dark, and follow-system themes
- • The library is now the home screen, with a navigation drawer everywhere; back returns there instead of quitting the app
- • New Settings screen: playback options, appearance, and library backup/restore
- • Back up and restore your whole library — tracks and saved loops — to a file
- • Saved loops and a Recent tracks list
- • Better beat detection with one-tap ½×/2× tempo fix
SHA-256 b14480dcd2397c89e28dd259b472103d6804daec58b8916d5035081ba6df9caf
Will it run on your device?
92%
- Runs on a broad range of modern Android versions.
- Multiple CPU architectures are covered.
- Aligned with the latest Android target SDK expectations.
Installation Guide
Open Settings on your Android device
Go to Security → Unknown sources (or Install unknown apps)
Enable "Allow from this source" for your browser or file manager
Open the downloaded APK file from your Downloads folder
Tap "Install" and wait for installation to complete
Launch the app from your home screen
Make sure to re-enable Unknown Sources restrictions after installation for security.
How to install this safely
How to verify the file you downloaded
Before you install anything, confirm the file is the one described here. On a computer, run shasum -a 256 your-download.apk (macOS or Linux) or certutil -hashfile your-download.apk SHA256 (Windows), then compare the output character-for-character with the SHA-256 on this page. If a single character differs, the file is not the build we recorded — delete it.
What the signing certificate proves
Every Android app is signed with a private key that only its developer holds. The fingerprint on this page is a hash of the matching public certificate, and it proves continuity rather than identity: it tells you a build came from whoever signed the earlier ones. Android enforces this at install time — if a package claiming to be de.singular.looper is signed with a different key, the system will refuse to install it over your existing copy. A fingerprint that changes between releases is worth pausing on, because a repackaged app that has been modified by someone else cannot keep the original signature.
How to roll back to an earlier version
If the current release misbehaves, 0.4 is the last build before it. Android will not install an older version code over a newer one, so you must uninstall Rubber Ring first — which clears its local data unless you have a backup. Reinstall the older APK only if its signing fingerprint matches the build you already trust, and check the API range: an older release may target an Android version your device has moved past.
Why we list sources instead of hosting everything
The official store channel is almost always the right choice: it updates automatically and carries the publisher's own distribution guarantees. A direct APK is useful when a device has no store access, when a rollout has not reached your region, or when you need a specific version — and only when the publisher has authorized that copy. APKBrowse does not list pirated, cracked, or unauthorized rebuilds of Rubber Ring, and a listing is removed when the evidence for it stops holding up.
Get Rubber Ring
Every source we list for de.singular.looper is legality-reviewed. Pirated or cracked builds are never offered.
Other sources
F-Droid listing
officialF-Droid builds this app from source and signs it. This is its official listing, with older builds and full release notes.
Source code
verified publisherThe upstream repository this build is compiled from.
We check legality and signature continuity, but device behaviour still varies. Install at your own discretion.
App Information
Security Verification
We record provenance; we do not run malware scans. Verify the hash yourself before installing.
SHA-256 Hash
f7007354106e9c5265809599d0cd5aee53c0ce797e9e00fb1e62ca29daec7182
Signing certificate
d27687051e30d6f7098dd66d686d2260c42aa4a9ad14aa61a08a4c255b78e9a5
Permissions Required
What each permission lets Rubber Ring do. A highlighted one is worth a second look — not necessarily wrong, just worth asking whether this app needs it.
Previous Versions
The signing certificate fingerprint for this release is on record, so a build that does not match it did not come from this publisher.
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