Jalmus is described as 'free, open source music education software helping the musicians, especially pianists, to improve their sight-reading. You can train to read music with both exercises on notes or rhythms' and is an app in the Audio & Music category. There are five alternatives to Jalmus for Windows, Linux, Mac and PortableApps.com. The best alternative is Impro-Visor, which is both free and Open Source. Other great apps like Jalmus are GNU Solfege (Free, Open Source), LenMus (Free, Open Source), ScoreDate (Free, Open Source) and noteable (Freemium).
Impro-Visor (short for “Improvisation Advisor”) is a music notation program designed to help jazz musicians compose and hear solos similar to ones that might be improvised. The objective is to improve understanding of solo construction and tune chord changes.
GNU Solfege is free music education software. Use it to train your rhythm, interval, scale and chord skills. GNU Solfege is an ear training program written to help you train intervals, chords, scales and rhythms.
LenMus is a free program for learning music. It allows you to focus on specific skills and exercises, on both theory and aural training. The different activities can be customized to meet your needs. It includes an score editor.
ScoreDate is your date with the music ! It is an open source software written in Java that helps musicians to learn music reading. It also helps you with ear training. It is suitable for any skill, from beginners to professional users. From slow training to first sight reading.