Smrt Stem ships updates as we find things worth fixing. We're honest about what changed: bugs, improvements, new features, all of it. If you want the short version, read the headline. If you care about details, each release below has them.
Cue by cue, Null, loudness and true peak, and a new look
The biggest update since launch, and free for everyone with a Smrt Stem license. Your license and settings carry over. Smrt Stem 1.1 needs macOS 13 (Ventura) or later. On macOS 12 or earlier, keep using 1.0.11: it stays available to download, and 1.0.11 won't offer you an update it can't run.
New
- Cue by cue. Every folder that holds audio is checked as its own cue: 1M01 and 1M02, or a song's 60s and 30s edits. Lengths, formats and timecode are compared inside each cue, so a 30 second edit never gets flagged against the full-length stems. Drop a whole episode or album and pick cues from the cue tree. The overall verdict is the worst cue. "Scan as one session" still checks everything together, the 1.0 way.
- Mixes are found for you. A MIXES or REF folder, files named as a mix, or a mix sitting next to its stems shows up as that cue's mix. Mixes are still checked for clipping, clicks and silence, but kept out of the length and format checks. When Smrt Stem isn't sure, it asks: "Is this a mix?"
- Null. Plays the stems against the polarity-flipped reference, so everything they share cancels and you hear only what's different: a missing part, a different take, a level change. A meter shows how loud the difference is. Null is for your ears only and never changes a verdict.
- The reference lives on the timeline. Each cue keeps its own reference, and a cue with one mix loads it by itself. Flip between STEMS, REF and NULL with B and N.
- Loudness and true peak for every file. Integrated loudness (LUFS), loudness range (LRA) and true peak (dBTP), in the app, the CSV and the PDF. Information only: no loudness pass or fail.
- New checks. Polarity Inversion (one side of a stereo file flipped), Mix Runs Past the Stems (the mix has sound after the stems end, so the stems may be cut short), and Near-Clipping now also catches a true peak at or above -0.1 dBTP. Click tracks are recognised by name and left out of the click check. Each check can be switched off in Settings.
- A fader on every stem, from -inf to +6 dB. Select several tracks at once and solo or mute them together.
- Pro Tools-style shortcuts, and a Help guide with a contents list.
- A new look, in Day and Night themes, with redesigned issue cards: what's wrong, which file, what was found, clickable times, and what to check.
- CSV and PDF reports cue by cue, with loudness and true peak for every file and phase correlation for every stereo file.
Improvements
- Faster scans. Each file is decoded twice instead of up to six times, and files are scanned in parallel. Drop new files during a scan and it switches straight to them.
- A new built-in audio decoder (FFmpeg 7.1.5, LGPL), and a smaller download.
- Play while a cue is loading. Press Play or Space and playback starts as soon as the cue is ready.
- Playback rides out output changes. Switch headphones, an interface or the sample rate while playing, and playback pauses and comes back by itself.
- Loops wrap around without a gap.
- A newer, more secure app framework under the hood.
Fixes
- Resolved an issue where clicks and pops were only looked for in the first 10 minutes of a stem. Long stems are checked end to end.
- Resolved an issue where long stems (over about 22 minutes at 48 kHz stereo) got "Clipping Check Incomplete" instead of a full clipping check.
- Resolved an issue where a check that couldn't finish on a file could pass without a word. It now shows a "Check Could Not Complete" warning that names the check.
- Resolved an issue where FAIL issues were listed after the warnings, in the app and in the PDF.
- Resolved a rare issue where pressing Play gave silence, or loading a reference mix stopped playback.
- Resolved an issue where a 16-bit and a 24-bit WAV were reported as Mixed Formats as well as Bit Depth Mismatch.
- Resolved an issue where Cmd+M, Cmd+L and Cmd+B also muted a track, set the loop or switched A/B.
- Resolved an issue where the stats bar's Duration showed the average stem length. It shows the longest stem, the length of the session.
- Report fixes: the CSV opens in Excel with accented and non-Latin file names intact, a file name starting with "=" can no longer run as a formula, and every issue names its stems; the PDF prints non-Latin file names, lists issue details one stem per line, and a long folder path no longer overlaps the "Generated" line.
Stem length checks that say what's wrong, and waveforms that line up
Improvements
- Four stem length checks replace Duration Mismatch. When a stem isn't the same length as the others, Smrt Stem tells you which case it is. Stem Cut Off (fail): the stem ends while it's still sounding and another stem is still playing, so audio is missing. Start Points Don't Match (fail): the stem is a different length from the others and its BWF timecode shows it starting at a different point. Different Lengths (Silence Only) (warning): the only difference is silence at the end, like a trimmed FX stem or extra silence on a bounce. Different Lengths (warning): anything else, such as the stem that plays the last hit running past the others. Often fine, but check it by ear.
- Each length check has its own switch in Settings, on by default. If you trim every stem to its own end on purpose, switch off the checks you don't need. The verdict follows, and the PDF report shows which checks were off.
- A few sessions may be rated differently than in 1.0.10. The length checks look at whether audio is missing, not at the size of the gap. A stem with sound past the end of the others is a warning instead of a failure. A stem that stops a fraction of a second early while still sounding, as another stem keeps playing, was rated Slight Duration Variance in 1.0.10 and is rated Stem Cut Off in 1.0.11.
- Update notifications check your macOS version and only offer updates that will run on your Mac. This prepares for Smrt Stem 1.1, which will need macOS 13 (Ventura) or later.
Fixes
- Resolved an issue where a stem or reference mix shorter than the others was drawn stretched across the whole timeline, so its waveform didn't line up with what you heard. Playback was not affected.
- Resolved an issue where turning a check off hid its issues but not its verdict, so the banner, PDF or CSV could still show WARN or FAIL. The verdict follows your settings everywhere.
- Resolved an issue where CSV reports split issue details onto stray rows and showed internal markers in click and clipping timestamps.
More precise checks and smoother session switching
Improvements
- More precise clipping detection. Clipping is identified by runs of clipped samples (three or more in a row at full scale) rather than by peak level alone, and pinpointed with timestamps in 16-bit, 24-bit and float files. Stems that run hot without clipping get a Near-Clipping warning.
- Finer peak readings. Peak levels are measured with greater precision and shown to two decimals (for example -0.03 dBFS) in the app, PDF and CSV.
- Guidance for MP3 and AAC files. Lossy files that clip on playback are flagged with an explanation: encoding can push peaks above the level of the original file, so leave headroom before encoding (-1 dBFS or lower is typical).
- A clear notice on very long files. If the clipping check can't cover a whole file, Smrt Stem tells you, so you know to check those passages by ear.
- Leading silence is measured from the very start of each stem, so pauses later in a stem aren't counted.
- A folder containing only unreadable files is reported as a failure.
- Heads up: because the checks are more precise, rescanning a session may give a different result than before.
Fixes
- Resolved an issue where drop-frame timecode in PDF reports could differ from the app and CSV. All three match exactly.
- Resolved an issue where dropping a new folder while the previous one was still loading could mix the two sessions. Each new folder cleanly replaces the previous one.
- More reliable playback after an interrupted load, and stems re-exported under the same name are always re-read.
- Cleaner issue text in PDF reports.
Playback fix for stems of different lengths
Fixes
- Resolved an issue where playback could stop partway through a session when one stem was shorter than the others. Audio would go silent while the play button stayed lit, and moving the playhead forward didn't bring it back. Shorter stems fade out cleanly at their own end, and the rest keep playing to the end of the session. This update is recommended for everyone.
Stereo playback fix
Fixes
- Resolved a stereo channel issue where the left and right channels could play swapped on stereo stems. Mono stems were unaffected. If you work with stereo material, this update is recommended.
Improvements and fixes
Improvements
- Better handling of non-audio file drops. Dropping non-audio files onto the main drop zone now shows a helpful toast message listing supported formats, instead of routing to a blank error screen.
- Smoother seeking and scrubbing. Playback is now cleaner when clicking around the waveform or holding arrow keys to scrub through a track.
Under the hood
- Improved version comparisons for pre-release builds, removed stale fallback strings, tightened internal code structure, and various cleanup across the codebase.
Cleaner playback starts, plus behind-the-scenes improvements
Fixes
- Resolved an audible click-pop at the start of playback when replaying from the beginning of a track. This covers pressing Play when the playhead is at the start, using Jump to Start, and replay after a track ends.
Under the hood
- Updated internal components to address security advisories. No changes to how the app works.
Refined trial and license experience, clearer drag-and-drop feedback
What's new
- Drop a folder onto the results view to start a new scan. A neon-green visual affordance confirms the drop target, so you can queue up the next batch without returning to the welcome screen.
Improvements
- Clearer feedback for every drag-and-drop interaction. Both the main drop zone and the reference mix drop zone now surface toast notifications for every drop outcome, including files that aren't from Finder, empty drops, and unsupported formats.
- Trial badge refreshes throughout your session. If your trial ends while the app is open, you'll see a toast notification in real time instead of a stale countdown.
- Context-aware trial and license screens. The trial expiry screen adapts its heading based on whether your trial just ended or you opened the license view yourself.
- Detection toggles respond instantly. Switching click or clipping detection on or off hides and shows the waveform markers immediately.
- Refined update banner layout. Improved how the update-available banner sits in the interface across window sizes.
Under the hood
- Single-instance lock to prevent duplicate launches, cleaner process cleanup on quit, and more resilient handling of license activation and deactivation. Plus various reliability and stability improvements.
Apple Silicon performance and reliability improvements
What's new
- Faster launch and improved memory use on Apple Silicon Macs. Addressed a performance issue where the app could take 30+ seconds to launch the first time on modern M-series Macs (M1 through M4). Launches are now fast on first run and every run thereafter, with reduced ongoing memory use.
Fixes
- Improved track reordering. Refined how mute and solo behave when tracks are dragged to reorder them, ensuring both controls target the correct audio file. Also refined drag-and-drop positioning for smoother track rearrangement.
- Smoother pause, stop, and playback transitions. Playback transitions now use a fast fade to eliminate audible clicks on pause, stop, and at the natural end of a track. Also improved how playback recovers when the system is briefly under heavy load.
- Improved handling of filenames with quote characters.
Under the hood
- Various reliability and stability improvements.
Reliability hotfix
Fixes
- Improved license validation resilience. Hardened how the app handles unexpected responses from the licensing service. Short-lived service interruptions no longer affect active licenses.
- Clarified click detection scope on long files. Extended the click detection analysis window, and added an informational note in scan results when files exceed the analyzed duration so you always know exactly what was checked.
- Restored in-app purchase flow. The "Buy Smrt Stem" and trial badge links now open the correct checkout and license screens.
Playback and offline reliability
Fixes
- Fixed playback pitch on non-48kHz systems. Playback is now always at the correct pitch regardless of the system audio output sample rate.
- Truly offline operation. Removed a font CDN dependency so the app no longer makes outbound network requests at launch. Fonts are now fully bundled.
Activation and trial signup fixes
Fixes
- Fixed license activation. Resolved an issue where valid license keys were being rejected during activation.
- Fixed trial email signup. Trial signups now reliably reach our system.
Public launch
What's new
- Smrt Stem is live. A desktop quality control app for stems. Checks sample rate, bit depth, channel count, duration, clipping, silence, glitches, clicks, and pops across every file in a folder, in seconds.
- 14-day free trial. Full functionality, no credit card required.
- One-time purchase. $59 USD. Two-machine activation. No subscription, ever.