You may have heard that open-back headphones are supposed to be better for mixing music than closed-back designs.
I heard that too, but I prefer to mix my music using speakers since I like to hear the sound in the room. There’s a sense of space that’s usually missing with headphones.
When I’m recording I normally just use standard closed-back hi-fi headphones, or even my phone earbuds, since the sound isn’t so critical at that stage in the production process.
This meant I was in no rush to buy open-back headphones for mixing music, until now. So what changed? Well, it’s because of the Coronavirus lockdown. Music production in my home studio has become more difficult.
Headphones let you mix music quietly
Being in the house everyday with my family meant that it wasn’t really practical to be mixing using speakers, especially late at night. Even though the volume isn’t usually all that loud, my home studio is just a room in the house with no proper soundproofing.
I tried mixing tracks using my standard closed-back headphones but I quickly found that it wasn’t working too well. These headphones are designed to emphasise certain frequencies to make music sound good, and that’s not very helpful when you are trying to listen carefully to tracks you are mixing.
You need to be able to hear what the music actually sounds like without any parts being enhanced by the headphones. The expression often used to describe this is “flat frequency response”.
Both open-back and closed-back headphones are available that have a flat frequency response, but I kept hearing that open-back is better for mixing.
I decided to find out more about open-back headphones, how they are different from closed-back headphones, and why that helps when mixing music.
Open-back headphones are better for mixing music because the open design allows air to move in and out of the ear cups. This means that you don’t get a build up of pressure inside, which results in a more natural sound. This is important when mixing because it’s important to be able to accurately hear the audio signal coming into the headphones.
Different Types of Headphones
I should note here that we are talking about studio headphones for mixing music tracks. It’s the natural sound that truly represents the audio that is the important thing, rather than making the music sound good by adding something like bass-boost (which is what you sometimes get with consumer headphones).
It helps to look that the differences between the different types of headphones. However, since we’re thinking about headphones as a substitute for studio speakers, let’s start with speakers.
Studio Monitor Speakers
The speakers found in music studios are referred to as studio monitor speakers. These speakers are different from domestic speakers because they are designed not to alter the sound. This is the flat frequency response referred to earlier.
A flat frequency response means that the volume level is the same across the whole range of frequencies that people are able to hear. This is usually stated as 20Hz to 20kHz (20,000 Hz).
Domestic speakers include circuitry that can emphasise certain frequencies, so they aren’t really suitable for studio work.
The sound that comes out of speakers reaches your ears in more than one way. For example, there is the sound that comes directly to your ears from the speakers, and there is also the sound that is reflected back from various surfaces in the studio.
These reflected sounds provide a sense of space that you can lose when using headphones.
This is the type of headphones that you probably use to listen to music on your phone. Professional mix engineers probably wouldn’t use in-ear headphones, but you can’t ignore their convenience.
I use them all the time when arranging tracks, i.e, just moving parts of an arrangement around and listening as I go. I often do this on my laptop while sitting on the sofa, and since the quality of the sound at this stage isn’t really important, in-ear headphones work great for this.
Disadvantages of this type of headphone include the tiny “drivers” that produce the sound. The driver is the part of a speaker that produces the sound, and the lack of room in these headphones means the frequency range, especially bass, can be limited.
Another disadvantage is discomfort – using them for long periods of time can case irritation to your ears.
On-ear headphones have the drivers inside cups that fit over your ears. The larger size of the drivers means that a much wider range of frequencies in the bass range can be produced.
As mentioned earlier, studio headphones need to have a flat frequency response, so that the sound is a faithful reproduction of the signal they receive from the audio output on your recording equipment.
There are two main types of on-ear headphone: closed-back and open-back.
The closed-back in this type of headphone refers to the cups containing the speaker drivers, with the cups completely enclosing the ears.
The closed back limits the amount of sound that can leak in and out, which provides good sound isolation. This means that when you are recording things like vocals there is reduced risk of “bleeding”, where the sound coming from the headphones is picked up by the microphone.
Closed-back headphones are also good when there are other people nearby who don’t want to be disturbed by sound spilling from your headphones. I’ve seen some Masterclass videos of production teams (it was people working with Timbaland and Armin van Buuren) working together, each dealing with a different part of a track, and the sound isolation provided by a closed-back design would be needed in this setting.
A closed-back design would also be helpful if you’re trying to work where there is a lot of background noise. This isn’t normally ideal but at least the closed cups would help to keep some of this noise out. Noise-cancelling headphones would do an even better job in this case (that’s a topic for another article).
Since your ears are totally enclosed with this type of headphone you are isolated from the outside world. Almost the only thing you can hear is the sound coming from the speaker drivers.
Since the sound can’t really escape from the enclosed cups the sound pressure can build up inside, which can affect the sound.
This can provide a feeling of the sound being inside your head and there isn’t much sense of the music being around you. This is something you do get with speakers due to the vibrations in the air and reflections from surfaces.
The “closed-off” feeling can make the music sound a little unnatural, even with headphones that produce a flat frequency response.
In addition to general ear-fatigue, closed back headphones can become quite uncomfortable after a while. Having your ears enclosed can cause heat and moisture to build up around your ears, which can make them feel hot and uncomfortable.
I didn’t really want to do a comparison – open-back vs closed-back headphones – but I thought it would be helpful to include some discussion of different types of headphones in the previous sections.
The thing I really wanted to do was look at why open-back headphone are considered better, or best, for mixing.
The name “open-back” can be a bit confusing. The back isn’t really open it’s just not completely closed. There are also semi-open-back headphones, which are a bit less open (or a bit more closed).
The open-back design has a permeable mesh or vents on the ear cups that allow air to pass through to the speaker drivers. This allows the headphones to produce a more natural sound because the vibrations produced by the drivers can move more freely in the air, without being reflected back immediately by the headphone cups.
Also, the air vents prevent a build up of pressure inside the ear cups, so the drivers aren’t having to fight against this and can more more freely.
This provides a more expansive listening experience. Even though the drivers are still directing the sound into the ears, the vibrations in the air can move around in a similar way to sound waves coming from studio speakers.
However, you still don’t get the sound reflected from surfaces in the room, so the sound can still be a little bit “dead” when compared to listening with studio speakers.
Disadvantages of Open-Back Headphones
The disadvantages of open-back headphones seem to relate to them being more easily damaged that closed-back ones. This is due to moisture or rain getting in through the air vents in the ear cups and damaging the drivers. Since we’re only really talking about using them in a studio here that shouldn’t be a problem.
In addition to closed-back and open-back designs, you can also get semi-open-back headphones.
Rather than having large vents or a permeable membrane that allows air in and out, like the open-back models, semi-open headphones have smaller vents in the ear cups.
This allows some air movement in and out, but the cups are partly closed, providing a little more sound isolation than the open-back type.
I’m not clear about the point of this design, which seems to offer both the advantages and disadvantages of open and closed-back headphones. Maybe that’s the point.
One advantage might be that you get some of the benefits of open-back headphones but that they are less easily damaged? Also, they seem be less expensive than open-back headphones, so maybe they cost less to produce. It’s hard to find any definitive information and some people seem to think it’s a marketing gimmick.
Acoustic Channel Crosstalk
Something else that isn’t part of the listening experience with any type of headphones is acoustic channel crosstalk. When sound is coming from stereo speakers both ears are hearing some sound from each of the two speakers. Also, there is interference produced by the sound from each speaker interacting.
Headphones isolate the two speakers so you don’t get this acoustic crosstalk. The air vents in open-back headphones doesn’t really allow any interaction between the sound from the drivers.
Although crosstalk isn’t necessarily desirable, it is part of the natural sound produced by stereo speakers and that would be lacking when mixing with headphones.
Virtual mix room plugins like Nx by Waves claim to be able to reproduce acoustic channel crosstalk when using speakers, in addition to reproducing other aspects of the sound is heard using speakers in a studio. You can read more about it here on the Waves website.
My New Headphones
Anyway, I bought some new headphones to help me with the need to mix my music while the house is full of people during the coronavirus lockdown.
I went for a pair of AKG K240 semi-open headphones. They’re a more recent version of the ones in the image at the top of this article. You can check them out on Amazon.
I chose them after reading and watching some very positive reviews online, and I’m really pleased with them so far.
I’ve been comparing them with speakers and other types of headphones and I’m starting to understand why open-back, or in this case semi-open-back, headphones are considered best for mixing.
Firstly, I can use them for a long time without my ears feeling hot and irritable. The ear cups are quite big and the headband is comfortable.
The open-back does allow sound in and out fairly easily. For example, I tried putting them on without any audio coming in to find out what I could hear. When listening to music coming from speakers in the room the sound is hardly muffled by the headphones at all.
Compared to closed-back headphones the first thing I noticed was how crisp the sound was. However, it didn’t really sound better and it can feel like something is missing in the sound.
This is probably because of the flat frequency response (no bass boost) compared to the regular consumer Sennheiser closed-back headphones that I had been using. This is actually desirable to get an accurate representation of the audio signal.
Compared to mixing with speakers? I actually like the sound produced by these AKG semi-open headphones. I don’t get the sense of isolation that can be a problem with closed-back headphones. If someone comes into the room and says something I can hear them just about as well as I could if I wasn’t wearing headphones.
This is quite a new experience for me and I’m really enjoying it. Mixing with headphones had always seemed like a bit of a compromise and I don’t feel that way so much now.
The semi-open headphones I’m using are really working well for me. Now I’m wondering if full open-back headphones would be even better, but they’re a bit more expensive so I’ll have to start saving up.