It's related to Wayne's response above. A guitar speaker is made to PRODUCE a characteristic guitar sound. It will have colorations and range limitations which complement the instrument. If you mic the speaker and record your guitar sound, then play it back through some decent studio monitors, they will REPRODUCE your guitar sound accurately. If you playback the recording through your guitar speaker, it will again add its colorations and range limitations. You won't get your original guitar sound, and you're not likely to get something better, either. If you have the gear, this can be a fun experiment.