Guitar Metronome — Practice Strumming and Picking

How does a guitar metronome work?

The page uses the browser Web Audio clock to schedule short synthesized clicks ahead of playback. The downbeat can receive a higher accent, subdivisions divide every selected beat into two, three, or four equal parts, and the guitar presets simply load useful combinations of BPM and subdivision.

The implementation uses one AudioContext and a 25 ms JavaScript look-ahead loop to place oscillator events up to 120 ms ahead on AudioContext.currentTime. Each click lasts about 60 ms: an enabled bar-one accent uses 1400 Hz, main beats use 900 Hz, and subdivisions use a softer 620 Hz tone. BPM ranges from 40 to 240, signatures cover 2/4 through 12/8, and the beat can be divided into one, two, three, or four equal parts. The four guitar buttons only load Chord changes 60, Scale alternate 80 with two subdivisions, Strumming 100 with two, or Funk 16ths 110 with four; no audio is uploaded and no guitar is analyzed.

The page generates a practice click; it does not listen to or grade a performance. Browser audio is scheduled against the audio clock, while visual changes can render later and background tabs may be suspended by the device.

How to get a useful result

Treat BPM as a repeatable practice condition rather than a score of musicianship. A useful tempo lets fretting and picking remain synchronized without bracing, squeezing, or shortening notes. Subdivisions can reveal where the motion is uneven, but the stronger test is to remove them or mute a bar and keep the same spacing internally. Raise tempo by only two to five BPM after several clean repetitions, and lower it as soon as tone or relaxation changes.

Define the practice condition before starting: Choose a guitar preset or set a BPM between 40 and 240 that allows relaxed, accurate movement. Decide what one click represents, use subdivision only as needed and record the BPM and meter so a later attempt is genuinely comparable.

When the click is not helping

• If chord changes still interrupt the beat, halve the number of changes, isolate one transition, and lower BPM until the strumming motion stays continuous.
• If every pick stroke follows a sixteenth-note click mechanically, switch to eighths or quarters and maintain the smaller divisions internally.
• If sound seems behind the beat light, disconnect Bluetooth audio and use wired headphones or the device speaker; the display and audio have different latency paths.
• If playback stops after locking a phone or changing apps, return to the visible tab and restart because mobile browsers can suspend its AudioContext.

Make the practice condition repeatable

Write down the BPM, meter, subdivision and what one main click represents. That note turns a vague impression of progress into a practice condition you can repeat tomorrow. Begin slowly enough that movement and sound remain controlled, complete several clean repetitions and raise the tempo in small steps only while the same technique remains intact.

Use dense subdivisions to diagnose uneven spacing, then remove some support and keep the smaller grid internally. Silent bars are another useful check: an early return suggests acceleration and a late return suggests slowing. Follow the scheduled audio click rather than the screen when Bluetooth or display rendering makes the visual pulse appear offset.