A free strobe tuner for 6, 7 and 8 string guitar. In your DAW.

Why low strings are hard to tune

A guitar's low strings vibrate slowly. A standard low E is about 82 Hz, a 7-string low B is about 62 Hz, and an 8-string low F# is about 46 Hz. Fewer vibrations per second gives a tuner less to measure at any moment, and a heavy, loosely tensioned string also drifts in pitch as the note dies away.

That is why a basic needle or LED tuner flickers back and forth on the thickest strings, and why a lot of heavy players tune by ear and still end up a few cents off. A cent is one hundredth of a semitone, small enough that you may not hear one string but you will hear a chord built on it.

What a strobe tuner does differently

A strobe tuner turns the gap between the pitch you play and the pitch you want into motion. In Rack, a ring turns while the string is out of tune and goes still when it is true. The note name and the number of cents off are shown underneath, so you see both which way to turn the peg and how far.

Rack reads every string of all six built-in tunings to within 0.3 cent in our tests. It holds still on a note instead of jumping, which is what you want from a tuner on a long, low string.

The tunings built in

Rack has presets for the tunings heavy players actually use: Standard, Drop D, Drop C, B Standard, Drop A and 8-string F#. Pick one and the string keys show the notes to tune to. The key for the string Rack hears lights up, so you can see which string it thinks you are plucking.

The reference pitch, A4, sits at 440 Hz and you can move it up or down if your band or your sample library tunes to something else.

How to use it in your DAW

1. Insert Rack on the track your guitar is recorded on.
2. Pick the tuning you are playing in.
3. Pluck one string and let it ring. Rack listens for a single note, so pluck strings one at a time.
4. Turn the peg until the ring goes still and the cents read zero.
5. Move to the next string, then play a chord to check. Re-check the low string last, because tuning the others can shift it.

A habit that helps: tune up to the note. If you overshoot, drop below it and come back up, so the string settles in tension instead of slipping flat later.

Does it change my sound?

No. Rack only listens. It does not touch your signal, so you can leave it on the track without changing the tone or the level.

What it is not

Rack is a tuner, not a pedal and not a chord reader. It works on one note at a time, and it is built for the tuning step in a recording session, not for tuning on stage. For that job, put it in your DAW's guitar track and tune before you hit record.

Get Rack, free

Questions

Is Rack really free?

Yes. Rack is a free download for Mac and Windows. You enter your email once on the Rack page and the download buttons appear. There is no license key, no trial and no subscription.

Which DAWs does it work in?

On Mac it comes as AU and VST3, so it loads in Logic Pro, GarageBand, Ableton Live, Reaper, FL Studio, Studio One and others. On Windows it is VST3, for FL Studio, Reaper, Ableton Live, Cubase, Studio One and Bitwig. Pro Tools (AAX) is not supported yet.

Can it tune a 7 or 8 string guitar?

Yes. Rack is built for 6, 7 and 8 string guitars. It has an 8-string F# preset and tunings from Standard and Drop D down through Drop C, B Standard and Drop A.

Can I change the reference pitch?

Yes. A4 sits at 440 Hz by default and you can move it up or down.

What does it run on?

Mac: macOS 12 or newer, Apple Silicon and Intel. Windows: 10 and 11, 64-bit. The Mac installers are signed and notarized by Apple.

More free plugins for heavy music are on the free plugins page, and the Mix Notes show these tools at work.