Thanks for your question.
You can use the
post_mime_type=audio parameter to limit the cloud to audio files. Be sure to include the
minimum=1 parameter to eliminate terms with no audio file assignments. Try something like:
[mla_tag_cloud taxonomy=attachment_category minimum=1 post_mime_type=audio]
I am marking this topic resolved, but please update it if you have problems or further questions regarding the above suggestion. Thanks for your interest in the plugin.