I recently forwarded this list to a couple teachers who were asking how to do an audio recording on Chromebook. Here are the ones that I have used from the list.
Voice Recorder - QUICK AND SIMPLE
Twisted Wave - FOR EDITING
TwistedWave is a full featured audio editor that allows you to: Edit audio files from your computer or your Google Drive, apply effects, save in one of many supported file formats, and export the file back to your disk, Google Drive or SoundCloud.