I mix on headphones a lot more than you'd probably expect from somebody who treats rooms for a living.

All of my mix prep happens on headphones. Going through the tracks, listening out for clicks and low frequency rumble and all that sort of stuff, is just easier that way.

When my buddy is in the room working on headphones, I'm on mine too. And a lot of the fun in dance music happens there, because the high end can carry a side to side groove on top of the front to back groove on top of the volume groove, and I want that to work for the people who'll hear it on headphones.

So when a client asked me near the end of a call this spring, "When is a good moment to put on headphones?", that’s the honest answer I gave him. You can do just about anything on headphones.

Still, balancing the mix is the one job I don't like doing there. I do balance on headphones, and it does work. I just find it easier on speakers, and most people I talk to feel the same way. Now I can't hand you a tidy physics reason for that. What I can tell you is why it matters so much: getting the level of every part right against everything else is about 80% of a mix. You can have the best sounding snare in the world and it won't save a mix whose balance is off.

What are headphones actually better at?

The fine detail. Delays, reverbs, the last part of a reverb tail where a change of 0.3 dB decides whether the space feels right. To hear that on speakers you need a VERY well treated room, and most home studios aren't there yet. A good pair of open-backs gets you that detail for a few hundred dollars (in my experience, upwards of about $300 is where headphones get properly usable).

The way I think about it, headphones are one more tool in your reference kit. The car is in there, your phone, the kitchen stereo, the in-ears you wear on a walk. Nobody worries whether checking a mix in the car is "allowed". You know what the car is good at telling you and what it can't tell you, and you use it for that.

Headphones are for detail, speakers are for balance, and the trick is knowing which one to believe when they disagree.

What if your speakers are the ones getting it wrong?

That same client from above had a mix with a bass guitar in one part of the song and a sub in another. He evened them out as best he could, on his speakers and on his headphones. Then he played it in his living room, and the bass guitar was way too loud next to the sub.

And his measurement explained exactly why! At his listening position there was a big hole from 70 to 100 Hz, followed directly by a pretty significant peak. Now your hearing never judges a level on its own, it compares it to everything else it's getting from the rest of the response. So give it a hole like that and your brain basically goes "eh, what's going on?". You end up pushing the bass guitar up until it feels right. And at your listening position it WILL feel right at that point. Of course everywhere else it's too loud now.

So speakers can only win the balance job when the low end where you sit is properly balanced.

Bobby Torres (Frightbox Recording), a mixer I interviewed a few years back, works in what is basically an untreated room. He checks his low end on closed-back headphones against three or four reference mixes he's known for over a decade, because his room can't show it to him reliably. That's a perfectly sensible call for his room.

And plenty of people mix mostly on headphones and make great records. If your mixes translate, keep doing what you're doing, and don't let anybody get dogmatic with you about it (me included). The warning sign is when the balance keeps fighting you. One reader wrote to me after seven years of mixing only on headphones, "a bit tired of going 10 times back and forward between my car and my PC." When that's your week, the balance job needs a better home, and that means working on the room, starting with where you sit.

How do you get the two to agree?

This is the step that makes the whole split work. Headphones and speakers will keep fighting each other as long as they're set up differently. Different tonal balance, especially in the low end, and a different level every time you switch.

You want to fix the tonal balance first. For example you could put a gentle low shelf on your headphones and push it until their low end sounds roughly like your speakers. Mine are a bit bass shy, so I give them a slight boost and that's all the correction they get. I do it on my interface, but a correction plugin works just as well.

Then match the level. There's no clever technical way to do this at home, you just tweak it by ear. Play something you know well, take the headphones on and off, and adjust until switching doesn't give you a volume jump.

Once the balance and the level roughly line up, a disagreement between the two finally means something. The headphones will catch those unwanted clicks, the reverb tail and the pan position your speakers might not show you. The speakers will tell you how loud the bass guitar should be, as long as your room lets them.