Improsax

A jazz practice partner built from a lead sheet. Pick a chord chart and your instrument, and Improsax plays the accompaniment, writes out the chord tones and scales that fit each bar, and gives you graded exercises and solo lines to read and play along with, transposed for your horn.

The idea

A chord chart tells you the harmony but not what to play over it. Improsax turns one chart into practice material: a backing track on one MIDI channel, a written practice line on another, and notation for both in your instrument's key and range. Everything follows the chart, so changing the key, the bars you loop or the instrument updates the whole session at once.

The lines are original practice material generated from the chords. Improsax does not know or recreate the melody of a tune; it gives you something to practise over its changes.

Getting started

Choose a study from the piece selector. Eight original studies are included: Major Cadence, Minor Cadence, Twelve Bar Blues, Waltz Cadence, Modal Pedal, Changing Keys, Slash Bass and Silent Breaks (in 6/8). Then choose your instrument in the header and press Play.

Playback goes to the MIDI instrument selected in the host: the backing on channel 1 and the line on channel 2. The speaker toggle next to Play and Loop switches the backing on and off. Pause keeps your place.

Your instrument

Saxophones sit in the main instrument menu; More lists B♭, A and E♭ clarinets, bass clarinet, flute, piccolo, oboe, English horn, bassoon, B♭ trumpet, F horn, tenor trombone and tuba, nineteen presets in all. Each sets the written range the lines stay within, and bassoon, trombone and tuba read in bass clef. You can edit the range or set a custom transposition.

Pitch · Instrument / Concert switches every chord label, scale and score between your written key and concert pitch. It changes only what you read, not what plays. Concert key transposes the whole song.

Practising

The lead sheet stays on the left, four bars to a row, with a playhead on the sounding bar. Click a bar to jump there. Shift-click, or the first and last bar fields under the chart, to loop a shorter passage; All returns to the whole chart. Chords / Roman switches the chart between chord names and Roman numerals.

The practice area on the right has three tabs:

• Ideas shows the current chord with its chord tones (guide tones highlighted), the scale recommended for the progression, and a four-bar phrase that follows playback. Hear phrase plays just those four bars; Return to selection goes back to your loop.
• Solo writes a free solo over the selected bars as a full score. Choose Take 1–3, or Off to silence the line. Each numbered set always recalls the same three takes, so you can come back to a solo you liked.
• Exercises offers six graded drills: roots, arpeggios, guide tones, connected scales, three-note motifs and a cadence phrase.

Line settings shapes the generated line. Start from the Classic, Spacious or Adventurous presets, then adjust density, swing, complexity and dissonance. Further controls decide how often a bar repeats or varies an earlier one, how many bars make a phrase, how often a chord change is marked by a note, and how long a line may run before it takes a breath. You can also override the scale and weight individual notes.

Export saves the current practice material as a MIDI file, with backing and line on their own channels, tempo and meter.

Bring your own chart

Import lead sheet…, the first option in the piece selector, accepts a text or JSON file, a pasted chart or a link to a file. It previews the title, meter, bars, sections and repeats before anything changes, and shows where any chord could not be read. Edit current chart opens the chart you are playing in the same editor. A chart in plain text looks like this:

@title Major Cadence Study
@key C
@meter 4/4
@style Medium Swing
[A] x2
Dm7|G7|Cmaj7|Cmaj7
[B]
Dm7:2,G7:2|Cmaj7:3,A7:1

Bars are separated by | and chords within a bar by commas. Chords share a bar equally unless every chord in it gives its length as :beats, counted in quarter notes (so a 6/8 bar lasts three). N.C. is a silent bar, % repeats the previous bar, and x2 after a section plays it twice. Structured JazzStandards JSON is also accepted, including repeats and alternative endings.

Limits

Charts contain chords only, so key labels and the harmonic picture are estimates from the chords. PDFs, images, MusicXML and encoded iReal links cannot be imported. Linking to a file works only when the website hosting it allows it; otherwise download the file and import it.