My first experience with headphones dates back to the Seventies when I was just a wee sound lad in my walker in my parents' living room, listening to Linda Rhondstadt on a pair of gigantic earmuffs my Dad had. (No wonder I became a metal head.) I wish I still had that photo because it was at that tender young age that I first started to notice the difference between cans and speakers.
Let me divert a little here and explain the term cans. Telegraph and early radio operators used to wear headphones that looked a lot like tuna cans, hence the term. Ear goggles is a more recent slang term but it's a lot quicker to say, "gimme the cans".
Fast forward to college and I wound up in possession of another pair of Seventies era cans that I made do for DJ work. But by the time I made my way through the music production department I finally needed to invest in something better. So I gave $20 to the Sony Corporation and bought that pair you see everywhere. (The V150, there are several in the office as we speak) At the time I wasn't trying to actually mix on them, just cue up CDs or sound effects.
Shortly though I was starting to mix bands in venues that required more PA than just speaker-on-a-stick. At that point I finally realized that I needed something I could actually hear at a gig. When there was something wrong with an input and I couldn't figure it out, I would much rather solo it in the cans than try to twiddle with it pushed up in the mix so I can hear. I got a pair from Audio Technica that I thought I loved until they got stolen years later and I found out how much better things could be.
It wasn't until there were quite a few gigs behind me that I started to really work headphones into my sound check procedure. Having mixed festival style quite a bit I'm pretty good at doing five minute changeovers with two minute sound checks. But there have been some times where it wasn't possible for me to do a live check through the mains. So, listening to recorded music in the mains and having heard previous acts, I knew roughly where I stood. On go the cans and I do my line check soloing one channel at a time. If the system sounds good, all I have to do is make each channel sound good and then tweak a little once the band finally starts. If there's something about the setup that's going to throw me off, I can account for that a little in the process.
When I met my business partner a few years ago he was using a pair of Sennheiser 280. I grabbed a pair so we'd have a common reference point and got some others who work with us to do the same. Turns out we made a good choice. List after list of headphones came out and the 280s were almost always ranked at the top. They're really about the best you can do for less than a hundred bucks. There's a 64 ohm version that I bought because the lower impedance allows for higher SPLs, and that counts when you're trying to solo in front of a big PA. There's a higher impedance model that is a little more sensitive to detail, but I don't mix on headphones so I had no interest. When I started my last job I was pleased to find a few 280s around the office to offset the Sonys.
But let's flip to the studio side for a minute. With the popularity of pocket sized music players and bud earphones does it make sense to mix to that audience? The answer is not only no but HELL NO! You need to make sure your mix is going to sound good on good equipment. If it does then it should transfer well to playback methods with lower fidelity. The reason is this, only the very best speakers can give you the type of clarity in the highs that you can get out of cans, and that only if they're set up right. If you mix something in headphones, when you take them off your reverb tails are likely to go away, the bass will probably be off, and the panning as well, and that's if you didn't screw up a bunch of other stuff too. But if you do a good job on speakers first, then when you slip on the cans or pop in the buds, you should have roughly the same experience but you can hear some of the fine detail a little better, and you won't feel the bass but you should still experience it. It should really sound pretty much the same but give you a few nice surprises.
Try it yourself and see. I've been forced to mix stuff in a hurry, on a laptop, with buds and I got away with it only because the client knew it would be a rush mix, but also because as a live sound guy I'm used to mixing in one place to make things sound right in another place. Like when I walk down front at a show and then compare that to what I hear at the mix as I adjust. I've had a lot of practice at that so I could pull it off to an extent, but it was a lot of work and you can see how it might be better to conserve brain power and just mix where you're at instead of where you're trying to be. Going back to the example from sound checking, I'm usually not matching the inputs to the system, I'm just making them sound good and they usually still sound good when I bring up the mix in the house.
That's just dipping a toe into the world of headphones. If you're an audiophile you can easily invest thousands in a pair, and then tens of thousands on exotic monoblock tube amps (one for each ear of course). But really where a lot of people are at, especially with the advances in home recording, is just needing a fairly decent pair. The last bit of advice I'll give is to not use any of the hip hop style bass enhanced models, you're just asking for it. Save those for recreational listening or checking a final.
Go ahead and light up the comment section. I'd love to hear your two cents.