Audio quality (how easy is it to understand what is said)

What audio quality characteristics would a tutorial include in order to qualify as:

Characteristic

Approaching

Meeting

Exceeding

Clarity

Hard to understand what the person is saying, critical words are unintelligible (mumbled speech)

The audio is understandable, but makes few stutters and pauses through the video.

The voice quality is crystal clear and the enunciation is great.

Volume

Sound is poor, and the volume levels are inconsistent

The sound is average. The volume levels are inconsistent at times.

The projection is good, and the volume is consistent throughout the whole video.

Synchronization

Audio skips ahead or falls behind of instruction (the audio does not match with the actions in the video).

There are minor synchronization problems with the video.  (ex: audio makes sense and the audience does not get lost but it is not perfectly synced up to the actions of the video)

The audio syncs perfectly with what is being shown on screen (no error at all)  

Background Noise

The background noise is grainy and distracting

Very few background noises

The only thing audible is the person speaking into the microphone and the mouse clicks.