Hydrogen is a good, free Windows software, being part of the category Audio software with subcategory Editors (more specifically Synthesizer & Beat Machines).
It's available for users with the operating system Windows 98 and prior versions, and it is only available in English. Its current version is 0.9.3 and the latest update was on 5/24/2011.
Since the program joined our selection of programs and apps in 2011, it has managed to obtain 256.184 installations, and last week it gained 96 installations.
About the download, Hydrogen is a reasonably light software that doesn't need as much storage space than the average program in the section Audio software. It's very heavily used in some countries such as India, United States, and South Africa.