Denemo is described as 'GNU Denemo is a music notation editor that lets you rapidly enter notation for typesetting via the LilyPond music engraver. You can compose, transcribe, arrange, listen to the music and much more' and is an app in the Audio & Music category. There are more than 50 alternatives to Denemo for a variety of platforms, including Windows, Mac, Linux, Online / Web-based and iPhone. The best alternative is MuseScore, which is both free and Open Source. Other great apps like Denemo are TuxGuitar (Free, Open Source), AudioTool (Free), Guitar Pro (Paid) and OpenMPT (Free, Open Source).
With TuxGuitar, you will be able to compose music using the following features Tablature editor Score Viewer Multitrack display Autoscroll while playing Note duration management Various effects (bend, slide, vibrato, hammer-on/pull-off) ...
Make music online with a powerful set of tools ranging from synthesizers and samplers to mixers, delays, reverb and much more. AudioTool is an advanced, collaborative DAW (Digital Audio Workstation) built for the browser.
Guitar Pro is first and foremost a program designed to edit tablatures for guitar, bass, and other fretted instruments from 4 to 8 strings. Its great ease of use and the success of its specific file format have made it a program used by guitarists worldwide.
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.
Aria Maestosa is an open-source (GPL) midi tracker/editor. It lets you compose, edit and play midi files with a few clicks in a user-friendly interface offering keyboard, guitar, drum and controller views.