Tab mode is experimental. Here’s what that means.

What gets detected

• Pitch and timingfor notes in the guitar range (E2–E6). The polyphonic transcriber reads the isolated guitar stem and emits onset, offset, pitch, and velocity per note.
• Fret and string assignment. A dynamic-programming pass picks a playable fret/string for every detected pitch. It prefers positions close to the last note and realistic hand spans, which rules out the mathematically valid but physically unreachable mappings a naive solver would pick.
• Rhythm. Note durations are quantized to 1/16 notes against the detected beat grid. Column widths in the rendered tab scale with duration, so a whole note takes more horizontal space than an eighth.
• Bends. Flagged when the pitch contour rises ≥80 cents above the nominal pitch and either returns to it or holds there. Rendered as 5b7 (bend from fret 5 toward the sound of fret 7).
• Slides. Flagged between consecutive notes on the same string when the pitch glides monotonically from one to the next. Rendered as 5/7 (upward) or 7\5 (downward).

What doesn’t get detected (yet)

Non-goals for v1. Each of these is on the v1.1 backlog, but today they’re out of scope:

• Hammer-ons and pull-offs
• Palm muting
• Vibrato
• Natural or artificial harmonics
• Tapping
• Automatic tuning detection (you tell us on upload)
• Automatic capo detection (you tell us on upload)
• GP5, GPX, or MusicXML export (PDF only for now)
• Bass tabs and drum tabs

What tab mode does well

• Exposed playing. Unaccompanied intros, solos held over a single chord, the fade-out outro. A sparse texture with clear note attacks gives the polyphonic transcriber the best shot at pitch and timing.
• Clean acoustic and lightly-overdriven electric. One guitar track, clear note attacks, no backing band is the ideal input. Most pitches and timings will land right, with bends and slides caught on the obvious licks.
• Standard tuning and capo positions. Supported tunings on upload: E standard, Eb (half step down), Drop D, D standard, DADGAD, Open G, Open D. Capo 0–12.
• Mid-range register.Notes around the 2nd–12th fret are most reliable. Very high register (above fret 15) and very low-tuned bass territory are both rougher.
• Rhythms quantized to 1/16. Straight-eighth rhythms and 1/16 subdivisions come out cleanly. Triplets and swing feels get rounded to the nearest 1/16 and may need manual correction.

Where tab mode struggles

• Heavily distorted electric. Saturated tones smear the pitch content and inflate the harmonic series. Missed notes, doubled notes, and false bends are all common on dense distorted parts.
• Very fast passages.Shred lines, rapid 16th-note runs, and anything where adjacent notes blur into each other push the transcriber past its temporal resolution. You’ll see notes dropped or merged.
• Dense full-band verses and choruses. Once bass, drums, and vocals pile in behind the guitar, the source separator has a harder time isolating the stem cleanly. The intro before the band enters, and the outro after they drop out, will almost always transcribe better than the middle of the song.
• Multiple layered guitar tracks. The source separator emits one combined guitar stem. Two guitars panned hard left/right still collide in the transcription, and the DP arranger may attribute notes from Guitar 2 to a Guitar 1 position.
• Fast legato passages.Hammer-ons and pull-offs aren’t detected as such. They show up as plain sequential notes even though they aren’t re-picked in the audio.
• Open strings over capo. If you forget to set the capo on upload, the whole tab is transposed wrong. The fix is to retry with the correct capo, not to manually transpose one note at a time.
• Songs off A=440. Any detuning from concert pitch confuses the transcriber. Tune your recording before uploading, or upload a tuned re-record.

How to get the best output

1. Record or isolate a single guitar track. The cleanest input is a DI or mic’d recording of one guitar, no backing track.
2. Pick a clean or moderate-gain tone. Saturated metal tones will not give you a useable tab. If you’re playing distorted in the final mix, track a clean pass for Chords.fm specifically.
3. Set the tuning and capo correctly on upload. We don’t auto-detect either. They’re form fields on the upload page.
4. Edit obvious mistakes in the viewer. Every note is editable: wrong fret, wrong string, bend that didn’t happen. Click the note, fix it, save. Edits are saved back to the rendered tab so re-opening picks up your corrections.
5. Don’t try to edit pitch or timing. The editor lets you change fret, string, and technique flag. It does not let you change pitch or timing. If the transcriber missed notes entirely or misplaced them in time, the right recovery is to fix the source recording or wait for v1.1.

Report a wrong note

Tab mode gets better when we see real recordings that produced bad tabs. The viewer has a “Does this look wrong?” link under every tab that opens an email with the tab ID attached. Paste a screenshot of the wrong section, describe what the recording actually plays, and we’ll use the report to tune the bend/slide thresholds and the fretboard arrangement DP for v1.1.

If you’re comfortable sharing the source audio that produced a bad tab, that’s the most useful thing you can send. The pipeline is deterministic on the input, so we can reproduce the exact failure and fix it.