What's the difference between warmth and woolliness? I often hear them used synonymously.
Well I would cite a track like Rocket Man by Elton John as having a warm sound, even though it's beautifully clean and clear - originally recorded with analogue, obviously, but I don't think it is necessarily the analogue that is giving it the warmth. I would think it's more to do with the musical arrangements and the way they worked in the studio.
One modern band whose music I like, but whose sound I don't like is Franz Ferdinand - I would describe their sound as woolly. I found this
snippet, which kind of explains some of it, I think:
So then I mixed them in Pro Tools. At first I had problems with them because when I just mixed them normally, they tended to sound a bit wimpy and clean, '80s kind of sounding. Then once I realised they'd been recorded with a bit too little compression, I started to experiment putting the whole mix through the Neve compressor. And that was quite good, until I actually did something that you're not supposed to do. I actually put the whole mixes through [Line 6's plug-in] Amp Farm...
In other words, they record something that sounds a bit "wimpy and clean", then scuzz the whole mix up with some analogue-style plugins. It's not a great sound, it seems to me.
I'm sure I can think of some more examples if I put my mind to it.