I have some knowledge of mic'ing acoustic guitars and there are some similar issues. In particular, with an acoustic guitar, most of the sound comes from the so

I have some knowledge of mic'ing acoustic guitars and there are some similar issues. In particular, with an acoustic guitar, most of the sound comes from the soundboard, which is also the case for a violin and cello. With the bigger instruments I can definitely see the issue is that the soundboard and whole body are enormous. For acoustic guitars, the typical advise is to use a condenser mic and aim it at the 12th fret (avoiding most of the fret noise and not getting too boomy from the bass of the body/soundboard), about 12 inches away using a mic stand. I think condenser mics are pretty much the best option here as well. Personally I don't like the sound of a close-mic'd acoustic guitar. Unlike cello and violin, there can be a lot of fret noise and wound strings can be quite squeaky. Classical guitars have different, quieter wound strings under less tension, and nylon for unwound. This is also to reduce fret noise and squeakiness, but personally I prefer the full sound of steel strings. I've been working a lot on getting my fretting technique more clean to eliminate all of that mess and sound more professional, but to be honest I actually prefer to hear my own guitar live in a quiet, resonant room and not through a recording. Bathrooms with tile are great, if a little small! Of course that sounds like complete garbage if you try to record it. But it is absolutely heavenly live :-) For the doublebass I can imagine you'd be best off with a mic stand at a couple feet away and seeing if you can get a mic that has a very narrow response angle (almost a directed mic). Cheers and happy recording.