It is required to provide sources for any audio files to be included. What your source is largely varies on the way you created this audio. If you created or edited your work in a computer program, you must provide the project files and any samples you used. The samples themselves may also be licensed under the CC-BY license, which by themselves do not require you to share the sources you used to create the sample. This means that you can use commercial programs to create a sample and include proprietary synths and effects, as the sample you create will be your work and you may choose to license it in every way you see fit. Especially: there is absolutely nothing wrong with using, for example, expensive VSTi plugins for your work, as long as you still share the project file containing the settings for that VSTi plugin. Even if the music is composed on a totally obscure platform (e.g. Mac OS 9, or Amiga), there is nothing wrong with providing whatever is the native format of that application (e.g. as a floppy disk image).
It is required to provide sources for any audio files to be included. What your source is largely varies on the way you created this audio. If you created or edited your work in a computer program, you must provide the project files and any samples you used. The samples themselves may also be licensed under the CC-BY license, which by themselves do not require you to share the sources you used to create the sample. This means that you can use commercial programs to create a sample and include proprietary synths and effects, as the sample you create will be your work and you may choose to license it in every way you see fit. Especially: there is absolutely nothing wrong with using, for example, expensive VSTi plugins for your work, as long as you still share the project file containing the settings for that VSTi plugin. Even if the music is composed on a totally obscure platform (e.g. Mac OS 9, or Amiga), there is nothing wrong with providing whatever is the native format of that application (e.g. as a floppy disk image).