Recording is one of those things that needs rules and the courage to break them. Sometimes personal weirdness works brilliantly, other times we take the risk and it fails miserably. We have conventions to follow or disregard. If it doesn't work, your technique gets slammed as flawed. If it works you invented an exception. We have so many exceptions. We even use terms in bizarre ways.
I hate the word stereo. Well, hate it when used poorly or inappropriately. If we have a stereo recording - it normally has some link to live performance. You close your eyes and when you press play, you can point to where people or sound sources are. We get a clue as to who is closest, and who is furthest away. That (in my book) is stereo. If you stand in a pub and there is a guy playing the guitar, what you hear is the guitar at some position - usually dead centre - and you hear the pub. The slot machine to the right, the opening and closing of the door to the toilets to the left and the general hubbub of lots of people dotted around. The guitar is NOT stereo, it's placed where a real guitar would be - probably equal in both speakers or headphones. Unless you are very close in, you hear one thing, a guitar. Go further in and your left ear and right ear hear different things. Step back and they merge.
My view is that we should follow this when we create perspective. Close miked guitar with one mic, and a stereo 'pub noise track' would be damn hard to tell from a real pub recording, wouldn't it? Does it matter? I don't think so. A voice is a point source - far more than a guitar - one mouth, a very small point source. There is no point using two mics unless they are distant and you want them to capture the room and the singer in the right proportion.
All this stuff about panning - we lost the point. Let's not think about studio monitors or home hifi - let's think about a live event where the speaker stacks are 15m apart (45ft for the non-metric) If you mic up a bigger instrument on stage - let's use a grand piano, the last thing you want is bass left and table right - the hard panned L/R example. Somebody playing double handed strident boogie or rock and roll piano would have the people to the right totally unable to hear the bass, and the people on the left would never hear the tune. So live sound mixers run near mono, unless there is a reason to widen it - maybe for effect. Worse is
Hammond organs and Leslie cabinets. two hard panned mics on a Leslie make the audience feel really uncomfortable with a 45ft Leslie cabinet!
That grand piano and Leslie might be panned 11 o'clock and 1 o'clock, but no more. In my recordings - most of the synth pad sounds are indeed 'stereo' but the reality is they are just not mono - there's no realism intended, just effect.
My rule (for me - not necessarily others) is that voices, guitars and small instruments are single channel, or two channel panned very close - maybe just capturing different elements off the sound? The bass warm sound hole and the zippy string noises from the fingers. I personally hate string noise, so I rarely mic up fingerboards. We follow convention unless we know better and deliberately do it differently.
