The 1.2.0 version of ADSRDrumMachine for Mac was available to download on the developer's website when we last checked. We cannot confirm if there is a free download of this app available. We recommend checking the downloaded files with any free antivirus. ADSRDrumMachine for Mac is included in Audio & Video Tools. This software for Mac OS X was originally created by ADSR Sounds.
From the developer:
ADSR Drum Machine is an application that allows users to create, program, and manipulate drum patterns and sounds. The utility features a virtual drum kit that can be customized with a variety of different sounds. It provides a wide range of editing tools, including the ability to adjust the volume, pan, and pitch of individual drum hits, and to create dynamic patterns by adding accent hits and ghost notes.
You may want to check out more Mac applications, such as Mixtikl 5, Speak or SH-201 Librarian, which might be similar to ADSRDrumMachine.