Accordion Sim

A free-reed synthesiser: real reed banks, register switches, Stradella bass and chords, and four Irish session tunes. Click anywhere to start the audio engine.

Accordion Sim

free-reed synthesis · 12 treble registers · Stradella bass · Irish tunes · live tone lab Play Mode →

Treble registers

Bass registers

What the dots mean

Each register opens a different set of reeds: top dot = 4′ piccolo, middle row = the three 8′ reeds (flat / true / sharp), bottom dot = 16′ bassoon. Two 8′ reeds slightly apart is what makes a musette beat; three is a full French musette.

Techno / trance / psytranceoptional
0.90
0.60
0.45

The kick lands on the tune's own pulse, so reels get four-on-the-floor and jigs get a 6/8 kick on the two dotted crotchets. Sidechain ducks the box under every kick. Variance adds fills, accents and note changes so it does not loop identically. Turn off bass + chords above if the Stradella vamp crowds the electronic bass. Drum & bass wants a faster tempo than a session reel — push it up towards 160.

Tunes

These are common session settings — trad tunes have no single correct version. Edit the ABC above (or paste any tune from thesession.org) and hit re-read ABC.

Playlist

Sets play straight through with no gap: each tune repeats the chosen number of times, then the next one starts on the beat. Click any tune in the list to start from there. The top 100 comes from thesession.org, ranked by how many members keep each tune in a tunebook.

Performance lab

Plays your list as a continuous set and arranges it as it goes: key-matched tune changes, register changes, the left hand dropping out for a solo and coming back, breakdowns and drops on the beat. Defaults are set to sound good; everything below is optional.

0.70
8

Moves it may use

Tone labpresets & 24 controls

Everything is live — drag while a tune plays. Settings are remembered in this browser.

Play it: click the keys, or use the computer keyboard — z s x d c v g b h n j m is C4 upward, q 2 w 3 e r 5 t 6 y 7 u continues from C5. The round buttons are the Stradella left hand: gold = bass note, below it major / minor / seventh. There is no key velocity, exactly as on a real box — loudness lives on the bellows pressure slider.