8-String Guitar Tuner Online — F#BEADGBE

An 8-string guitar in standard tuning is F#BEADGBE from the eighth string to the first. The added eighth string is F#1 at 46.25 Hz, a perfect fourth below the seventh string’s B1 and the lowest note the instrument produces. The other seven strings keep the seven-string pitches.

How to use it

1. Start the tuner. Press Start Tuner (Microphone) and give the browser microphone access. Audio is analysed on-device only. Rest the side of your picking hand on the strings you are not tuning — thumb damping keeps the other seven from bleeding into the reading.
2. Tune from the eighth string to the first. Working low to high adds the heaviest tension first, and the two low strings are the ones that move the neck most.
3. Tune strings 6 to 1 to standard if you are coming from a six-string. 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.
4. Set the seventh string to B1 (61.74 Hz) and the eighth to F#1 (46.25 Hz). Each is a perfect fourth below the string above it.
5. Use the harmonic ladder for the bottom two. The seventh string’s midpoint harmonic should match the open fifth string’s second fret, and the eighth’s should match the sixth string’s second fret; matching both confirms B1 and F#1.
6. Mute the other strings while you tune each one. With eight strings there is more sympathetic ringing, and the low F# shares its note name with nothing on the instrument, so a wrong reading is usually a nearby string rather than an octave partner.
7. Re-check everything. The two low strings add a large amount of tension; expect the strings you tuned first to drift sharp or flat as the neck settles.

8-string string frequencies

From the player’s side, the eighth string is the broadest and lowest of the set, and the first is the thinnest.

String	Note	Frequency (A4 = 440 Hz)
8th (lowest)	F#1	46.25 Hz
7th	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

The low F# and the instrument

F#1 is a demanding note to build around, and it shapes the whole instrument:

• It needs a heavy string. Reaching 46.25 Hz at a normal playing tension calls for much more string mass than a standard set’s low E. The eighth string is the thickest in the set by a wide margin.
• It benefits from a longer scale. A longer scale length raises the pitch a given string produces, so the low F# can be reached with less mass and less tension than a short scale would need. Extended-range guitars are commonly built longer than standard guitars, and multi-scale (fanned-fret) designs make the bass side longer still while keeping the treble side comfortable.
• It changes how the instrument is set up. Eight strings carry more total tension than six, and the low strings need nut slots and saddle travel that match their gauge. A guitar set up for a lighter tuning will not intonate or play cleanly at F# standard.
• It sits below most guitar speakers. Guitar cabinets roll off well above 46 Hz, so the fundamental of the low F# is often felt more than heard. The harmonics are what carry the note, which is also why the tuner can sometimes lock onto a harmonic instead of the fundamental.

Extended-range use

• Strings 1 to 7 keep the seven-string tuning. Everything above the eighth string behaves like a seven-string, and everything above the seventh behaves like a standard guitar, so familiar shapes transfer.
• The two low strings open up voicings. Roots on the eighth string with the chord voiced above them, and low pedal tones under higher movement, are the everyday uses of the range.
• Modern metal is the main home. Extended-range instruments are established in progressive and modern metal, where the low F# carries riffs and the upper strings carry melody and chords.
• Drop tunings go lower still. Lowering the eighth string from F#1 to E1 gives drop E, which restores a one-finger power-chord shape across the bottom three strings. This page’s preset targets F#BEADGBE.

Accuracy and limits

• The low F# 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 F#1 that window holds several full cycles of the string, so the low F# no longer sits at the edge of the detector’s period budget. The microphone’s roll-off below roughly 100 Hz is the harder constraint on this note, and that is true on any hardware.
• An octave jump is the weak-fundamental symptom. When the display leaps up to F#2, the detector has locked onto a harmonic of a weak or decaying fundamental. Mute the other seven strings, re-pluck firmly, and confirm against the eighth string’s 12th-fret harmonic.
• Phone and laptop microphones thin out below 100 Hz. F#1 arrives at the capsule far weaker than it sounds in the room, so damp the other strings and give the low eighth a firm pluck.
• B and E repeat two octaves apart. B1 is the seventh string and B3 the second; E2 is the sixth and E4 the first. A ringing upper string can make the display report the higher note of the pair while you pluck a low string.
• New heavy strings settle slowly. The two low strings stretch noticeably after they are fitted, so retune them several times over the first hour of playing.

Safety

• Never tune the eighth string an octave high. F#1 is 46.25 Hz; F#2 is 92.50 Hz. Aiming at the wrong octave on a heavy string is how strings and tuning posts break.
• Tune up to pitch in small increments. If a string is sharp, lower it below the target and bring it back up, checking the reading as you go.
• Do not force a stiff peg. A binding string in the nut slot is the usual cause. Ease the peg round rather than forcing it.
• Do not tune a slack low string sharp to fix rattles. If the eighth string feels loose or buzzes, the answer is a heavier gauge or a setup, not extra tension.
• Respect the total load. Eight strings pull harder on the neck and bridge than six. If the instrument is new to the tuning, have the setup checked before you play it hard.
• Check the whole instrument after tuning. A string that will not hold pitch, or a buzz that appears only in one position, is a mechanical issue rather than a pitch one.