Everyone is listening to music on headphones these days — but what about the people who make that music? Every music producer and mix engineer needs a monitoring system they can rely on, so what makes one pair of headphones more suitable for music production than another?
In this video, Sound On Sound Editor In Chief Sam Inglis introduces some of the most important things to think about when you're choosing headphones for studio use.
If you’re new to music recording, you might be thinking one pair of headphones is pretty much like another. A little speaker for each ear, band that goes over the top, cable that’s exactly the wrong length and trips you over in the middle of a session? Well, no they’re not, and you can even buy studio headphones that only have one earpiece. So I’m going to answer some of the most common questions about the different types of headphones, what they’re useful for in the studio, and what you need to think about when choosing them.
You might think I’ll get a pair of wireless headphones, and then I can use them in the studio and in the bath, or whatever. Sorry, no. Wireless headphones sound weird, they need charging up, and worst of all they introduce latency, a delay between the sound coming out of your computer and arriving at your ears. Also, if there’s one thing really you don’t want to be depending on in the middle of a session, it’s Bluetooth. I’ve known drummers that were more reliable. So, for studio use, you’re going to need old-school, analogue headphones with a cable coming out of them. But which ones?
The bit of a headphone that makes the sound is a diaphragm or membrane that moves backwards and forwards. And when it moves, it doesn’t just send out vibrations towards your ear. It puts out just as much energy in the opposite direction.
So, what happens to the sound coming out of the back of the driver? The idea of open-backed headphones is to let it all leak out into the air. The problem with that is now it’s not just me that can hear what’s playing. Everyone around me can hear it too, and so can any microphones that are in the room.
But if you don’t let the sound out into the room, it ends up bouncing around inside the earcup instead. And eventually it’s going to reach your ears along with the direct sound from the driver, and it’s going to colour that sound.
So, if you say “I want the best possible sound quality for mixing”, everyone will tell you to get open-backed headphones. But it’s not quite as simple as that. It’s true that most bad-sounding headphones are closed-back models. But this doesn’t mean closed-back headphones have to sound bad. Mostly, it means that cheap headphones are closed-back and cheap headphones are bad. That’s a bit like saying open-top cars are better than hatchbacks because the Mini Metro wasn’t a convertible.
What do we mean when we say we want the best possible sound quality? Well, most importantly, we want our headphones to have a flat or neutral frequency response. You might expect to see graphs of frequency response, like you get for microphones, so you can pick the ones with the straightest line. But you don’t, and the problem is that there isn’t a standard method for measuring headphone frequency response. You can’t meaningfully measure headphones without a head in them, and everyone’s head is different. And the frequency response actually changes depending on things like the wear on the ear pads, how they’re placed on your head, how bad your haircut is, and so on.
So looking at the specs won’t tell you if they’re flat or not, but what can you do is use headphone correction software. Companies like Sonarworks and dSONIQ will give you an EQ curve that will make your headphones neutral or flat according to whatever their idea of flat is, and it works very well in my experience. But even if your headphones aren’t completely neutral, you can learn to compensate for that as long as they’re not wildly out. And of course on headphones you don’t get all the problems that room acoustics bring when you’re working on speakers.
Why do we want a flat response from our headphones? Because we want to make decisions on them. And the time we need to make the most decisions is when we’re mixing.
Why do we want a flat response from our headphones? Because we want to make decisions on them. And the time we need to make the most decisions is when we’re mixing. If you have a good pair of headphones, or headphone correction software, you probably have a flatter frequency response than you will from speakers in most rooms. So they should be even better for mixing on, right?
Well, maybe. But there are other differences between speakers and headphones. When I screw up mixes on headphones, which obviously I never do, it’s not the frequency response that’s the issue. I’ll put the mix up on speakers afterwards and realise that the kick drum is far too loud, or the vocal level is all over the place, or I failed to mute the banjo. Because the problem with headphones at mixing is that they make it hard to step back and hear that bigger picture. If you can hear a picture. So, yes, you can do a lot of the mixing process on headphones but you need other systems to give you that overall sanity check.
For tracking you’d think you’re going to need the most isolation possible, and sometimes that’s definitely true. If the artist needs to hear a click track, and you don’t want a click track on the finished recording, you need to give them closed-back headphones. Even then, musicians will find ways of getting click bleed onto your recordings. I try to make sure I have the click muted in the control room and that way I know that if I’m hearing it, it’s because it’s coming through the microphone! And then I can hard-pan the click to whichever side they haven’t removed. Or I can give them the headphones with just one earpiece that I mentioned earlier.
But it’s worth thinking about why musicians and singers might want to take off an earpiece. It’s because they don’t actually want to be isolated from the sound they’re making. They need to hear the backing track but they also need to hear themselves in the room. And so for that reason, open-backed cans can be a good thing, because they don’t just let sound from inside out, they also let sound from outside in. One time in particular when I think that really works is when you have a band playing together in a room and they need to hear a guide vocal. If you’ve got drums and amps in the room, vocal spill from the headphones isn’t going to be a problem. And even if someone’s doing a vocal overdub to a backing track, if giving them open-backed phones means you get a better performance, maybe a bit of spill is a price worth paying.
One thing that is worth thinking about for tracking is reliability. If they’re going to be in use all the time by clumsy musicians, sooner or later things are going to break. You don’t want to have to throw the entire headphones away just because the cable is damaged or the ear pads have got torn. So good studio phones have lots of field replaceable parts — cables that unplug, earpads that you can replace and so on.
If you’re using headphones in the studio you need them to go loud. That’s partly because what you’re listening to is usually much lower in level than finished mastered music, and also because you might need them to keep up with a loud drummer or guitarist. How do we know whether any given pair of headphones will go loud?
If you want your headphones to be as loud as possible, then you’re looking for high efficiency and low impedance.
Well, there are two specs that matter here. One is the efficiency of a pair of headphones, and the other is their impedance. If you want your headphones to be as loud as possible, then you’re looking for high efficiency and low impedance. So you might be wondering why anyone makes high-impedance headphones. Well that’s because big studios often need to connect lots of headphones to the same headphone amp. And if you connect two pairs of headphones in parallel, you halve the total impedance, and so on. So if you’re going to have to give everyone in the orchestra headphones, you’d probably want to go down that route. Otherwise, stick to low impedance and high efficiency and you’ll be fine.
So you might have started watching this video thinking you only need one pair of headphones. By now you’ve probably realised that that isn’t true, and of course, if you record bands, you’ll need enough headphones for all the musicians. So it perhaps makes sense there to buy one good pair of open-backed headphones that you can mix on, and give to artists occasionally, along with a few pairs of cheap closed-back phones for musicians to use when tracking.
I hope this article and its video has answered some of your questions about headphones. If you want to know more, the July 2020 issue of Sound On Sound has a special headphones focus, including our cover feature where star recording engineers tell us how they get good results mixing on headphones.
Which just leaves the final and most important headphone question of all… Straight or Curly?