7-String Guitar Tuner Online — BEADGBE

A 7-string guitar in standard tuning is BEADGBE from the seventh string to the first. The added seventh string is B1, a perfect fourth below the low E of a standard guitar, and the other six strings keep their standard EADGBE pitches. With A4 = 440 Hz, B1 sounds at 61.74 Hz.

How to use it

1. Start the tuner. Press Start Tuner (Microphone) and allow microphone access. The detector listens locally, and nothing is uploaded. Attack matters on this instrument: use the pad of your thumb on the low B and a pick on the upper six strings — the thumb gives the seventh string a rounder fundamental to lock onto.
2. Tune the six standard strings first if the guitar is close to pitch. EADGBE gives you known references before the seventh string joins in. Targets: E2 = 82.41 Hz, A2 = 110.00 Hz, D3 = 146.83 Hz, G3 = 196.00 Hz, B3 = 246.94 Hz and E4 = 329.63 Hz.
3. Bring the seventh string up to B1 (61.74 Hz). A perfect fourth below the sixth string. Approach it from below: slacken the string, then raise it slowly to the target.
4. Confirm B1 with the seventh string’s harmonic. Touch the string at its midpoint for the B2 harmonic and compare it with the open fifth string’s second fret; if they agree, the low B is in the right octave.
5. Mute the other strings while you tune each one. A seven-string rings sympathetically, and the low strings are close enough in pitch that a neighbouring string can dominate the reading.
6. Re-check the whole set. Adding tension on the seventh string pulls the neck and can shift the strings you tuned first.

7-string string frequencies

The seventh string is the thickest and lowest on the instrument, and the numbering runs from the player’s side up to the thinnest, highest string.

String	Note	Frequency (A4 = 440 Hz)
7th (lowest)	B1	61.74 Hz
6th	E2	82.41 Hz
5th	A2	110.00 Hz
4th	D3	146.83 Hz
3rd	G3	196.00 Hz
2nd	B3	246.94 Hz
1st (highest)	E4	329.63 Hz

Why players add the seventh string

• It extends the range a fourth lower, not a fifth. B1 sits a perfect fourth under the sixth string’s E2. That means the lowest three strings spell B–E–A, not a power chord, so the seventh string is normally used as a low root or pedal note rather than as part of a one-finger shape.
• Everything above it stays standard. Because strings 1 to 6 keep their EADGBE pitches, chord shapes, scale patterns and licks transfer unchanged from a six-string. The extra string is an addition, not a retuning.
• Jazz uses it for low support. Seven-string players in the jazz tradition use the low B for bass notes under chord melody and for wider voicings that a six-string cannot reach without moving up the neck.
• Modern metal uses it for weight. Extended-range guitars are standard in modern metal, where the low B carries riffs and drop tunings. Lowering the seventh string to A1 gives drop A, which restores a one-finger power-chord shape across the bottom three strings.
• Why not just down-tune a six-string? Tuning all six strings down a fourth is the baritone approach: it lowers the whole instrument and needs much heavier strings and a setup. The seventh string adds the low register while leaving the other six at familiar pitches.

Getting a steady reading from the low B

B1 is the hard case on this page. The string itself is heavy and slow to speak, and the microphone hears less of it than of the treble strings. Below 70 Hz the detector switches to its decimated low-frequency path — 4x decimation of the 4096-sample buffer to 11.025 kHz, with the full 1024-sample decimated window (~92.9 ms) correlated — so the window holds several full periods of B1 and is no longer the constraint. A few habits make the reading steadier:

• Pluck firmly over the 12th fret. A soft pluck leaves the fundamental weak, which is what lets the display jump an octave.
• Mute the other six strings. Rest the side of your strumming hand across them. On a seven-string there is more sympathetic ringing to reject, and the low B shares its note name with the second string two octaves up.
• Hold the note for about a second. The reading settles as the string’s initial attack decays. Judge it after the transient, not on the first frame.
• Use the neck pickup on an electric. It hears more fundamental and less pick noise than the bridge pickup.
• Keep the guitar a hand’s width from the microphone. Moving closer raises the level of the low string without letting room noise dominate.

Accuracy and limits

• The low B is read on the decimated low-frequency path. For notes below 70 Hz a 33-tap Blackman-windowed sinc anti-aliasing filter decimates the analyser’s 4096-sample frame by 4x to 11.025 kHz, and the detector correlates the full 1024-sample decimated window (~92.9 ms). At B1 that window holds several full cycles of the string — more than the 2–3 periods that pitch-detection methods generally want. The limits that remain are the microphone and string decay, and those apply whatever hardware you use.
• An octave jump is the weak-fundamental symptom. When the reading leaps up to B2, the detector has locked onto a harmonic of a weak or decaying fundamental. Mute the other strings, re-pluck firmly, and confirm against the seventh string’s 12th-fret harmonic rather than trusting a single frame.
• Most laptop and phone capsules roll off under 100 Hz. The low B can sound massive in the room and still reach the microphone quietly, so pluck it with the thumb rather than a pick.
• B repeats two octaves apart. The seventh string is B1 and the second is B3. If the second string rings, the display can report the higher B — the right note name, the wrong octave. Compare against the string cards when it matters.
• A fresh seventh string settles slowly. A heavy low string stretches for a while after it is fitted, so expect to retune it several times in the first hour of playing.

Safety

• The seventh string carries real tension. If you are fitting a low B for the first time, check that the nut slot and tuning post can take the gauge, and bring the string up slowly rather than in one turn.
• Tune up to pitch. If the string is sharp, lower it below the target and bring it back up. Approaching from below seats the string on the post and holds pitch better.
• Never force a stiff peg. A peg that will not turn usually means the string is binding in the nut slot. Work the peg round gently instead of leaning on it.
• Do not tune the low B sharp to fix a floppy string. If the seventh string feels loose or rattles, the answer is a heavier gauge or a setup adjustment, not extra tension.
• A six-string is not designed for a seventh string. Converting one means cutting a new nut slot and having the instrument set up; most players choose a guitar built for seven strings instead.
• Check the whole instrument after tuning. If a string will not hold pitch or the neck buzzes, the cause is usually the setup, not the tuning.