This is a note about electric instruments reamping. I’ll try to keep it simple, considering mostly creative and practical side of this process, instead of technical.
Reamping – is a possibility to pass a recorded guitar (bass or whatever electric instrument you’d like) part through some analog amplification/processing stack, starting from stomps and preamplifier and to picking up with a microphone(-s) from a cabinet. You’re able to reamp any kind of signal (e.g., let it be the vox) in case it corresponds to the general creative idea of the composition.
What do we get? Once you’ve recorded some DI part (clean, unprocessed guitar or bass sound as it comes out of the pickups basicly), you became able to reamp it for namely infinite times with a variety of settings and positions. It significantly rises freedom extent while choosing an appropriate sound on the song mixing stage. One may easily change a cabinet, adjust the gain (distortion amount), put a compressor or a gate in front of a preamp – whatever you like. Another important preference is the editing ability: one may easily edit badly played rythm, cut/paste some single notes, tune a monophonic part etc. in case there is no possibility to re-record the part from the scratch. Nevertheless, it does not free a musician from the requirement to practice good rhythmic feeling and technique! 😉
Record monitoring. From the performer’s POV, it is important to understand that DI track recording does not mean to play and listen to the unprocessed clean guitar sound, while recording some metal riff with palm mutes. It would be very inconvenient to the most of musicians if one should have played something without hearing normal amplified guitar sound. Thus it is better to record both options at a time to have both the DI and the miced signal. It provides the necessary comfort level for the musician as well as the freedom for the mixing engineer to fundamentally change the guitar sound for a particular mix. Often it is also useful to use a DI signal along with an amplified one, letting them sound simultaneously in the mix – this approach appears most popular for bass parts.