In the video above, I demonstrate a sine wave sweeping from 20 Hz up to 4,000 Hz (4kHz). The test in the video looks something like this:
Then, we test this in the other direction… Sweeping from 4kHz back down to 20Hz.
Why Translation Is A Problem
If you took the test, two things probably happened: you couldn’t hear the lowest and highest frequencies and once you could hear the tones, some frequencies sounded louder than others.
There are a few reasons for this…
1) Your human ears tend to require more signal level at very low and very high frequencies compared to mid frequencies, especially as you suffer hearing damage.
2) Your speakers and room acoustics are impacting the relative level of each frequency across the spectrum.
3) Your speakers are not capable of producing low- and high-frequency sound at an audible level.
Luckily, most people don’t enjoy listening to test tones as much as they enjoy listening to music – and music contains many frequencies. So even though listeners might not be able to hear the lowest or highest frequencies within our music, they can still access the midrange frequencies.
That means that when we are mixing, we need to ensure that the intention of the music comes through within the midrange so it sounds good on a variety of speakers – from studio monitors and hi-fi systems to smartphones and cars.
A quick side note before diving deeper… I want you to go to audiouniversityonline.com/instrument-frequency-guide/ where you’ll gain access to a PDF that will help you understand where each instrument falls within the frequency range. This will hopefully save you a lot of time aimlessly searching for the right frequencies while mixing your music.
PART 1: Trust Your Speakers
To create the best mixes possible, your first goal should be to optimize the performance of the monitoring system that you use for mixing.
You might be working with a great pair of studio monitors placed in an acoustically treated room with the ideal speaker placement. Or you might be using the best pair of headphones that you can afford right now and making the most of what you’ve got. Either way, your goal here is the same.
A very important specification to consider when choosing studio monitors or headphones for mixing is frequency response. The frequency response describes the effect the speaker has on the sounds passing through it. As you can see below, the frequency response of a typical smartphone only extends from about 500 Hz to 15 kHz and the frequencies are not very balanced throughout that range.
Compare that to a bluetooth speaker, or a bookshelf speaker, or anything else and you’ll see that the same mix playing through different speakers will undoubtedly sound different.
Recently, I’ve been using these iLoud Precision 6 monitors, which were sent to me by the sponsor of this video, IK Multimedia. The Precision 6s have some unique features that will be very helpful in getting my point across to you throughout this video.
Looking at the frequency response graph for the Precision 6s (above), it’s clear that the engineers who designed them were aiming for a very flat frequency response, where each frequency is evenly balanced. This is also the case for the two pairs of $8,000 studio monitors that are shown alongside the Precision 6s on this graph. And it makes sense that they were each designed this way, because if the frequency response of your monitors is flat, you know that you’re hearing your mix as it truly is.
When shopping for studio monitors or headphones, you won’t always see a frequency response graph like this. Often, you’ll only see a range of frequencies. If you only see a range of frequencies, it’s important that you also see a tolerance as expressed in the frequency response spec for the Precision 6s.
This tells us that the frequency response graph doesn’t fluctuate by more than 1 decibel above or below the average level across that range of frequencies.
If these speakers overemphasized the low frequencies, I might have the tendency to cut out too many low frequencies in my mix. Or if they turned down the low frequencies, my mix would likely have too much low-frequency energy and sound very bassy. Just imagine the type of mix you might create if you mixed with a smartphone…
But even though these speakers have a very flat frequency response themselves, you can see below that the frequency response of these speakers in my room is far from flat. And that’s because the acoustics of my room play a role in the frequency balance by the time the sound reaches the listening position.
Every wall and every object within this room has the potential to impact the resonances and cancellations that could occur. I’ve already placed some acoustic treatment on my side walls to absorb the energy that would reflect off of those walls and back to my listening position, causing cancellations and build-ups of energy at various frequencies.
But I still have a ceiling above me and a desk in front of me – each reflecting sound back to the listening position. And on top of that, the dimensions of my room create the potential for resonations and cancellations all throughout the space. So it’s no surprise that the frequency response of my speakers combined with the acoustics of my room looks a lot different than the frequency response of my speakers alone.
Acoustic treatment is something I dream of perfecting within my space, but for now I’m just slowly improving it over time. And if you’re currently working in a less-than-optimal acoustic environment, there is another option that will help you make the most of what you’re working with – system calibration software.
These programs allow you to measure the performance of your speakers within your space using a measurement microphone and then apply a filter that corrects some of the buildups that occur. The calibration software I’m using is called X-Monitor, which comes with the iLoud Precision studio monitors along with an ARC measurement microphone that connects to each speaker via XLR.
After running a few test signals at four microphone locations around the listening position, the system applies a filter that makes the overall frequency response as flat as possible.
But you can see here that there are still a few cuts even after the calibration. That’s because the only way to avoid the cancellations that occur as a result of an acoustic reflection is to eliminate the reflection itself with acoustic treatment. Boosting those frequencies with EQ would cause an equal boost in both the direct sound and the reflected sound (which would still result in a cancellation).
Until I add some more acoustic treatment to my room this is as close as I can get to a perfectly flat frequency response. But if you look closely, you can see that these are only 3 dB dips, so not bad at all.
If your system isn’t perfectly flat either, you can try to make a mental note of its imperfections and with lots of practice and experience using your speakers in your room, your ears will grow accustomed to that sound.
But it’s important to note that you can only hear the frequencies your system can reproduce. If you were to mix on a system that has a very severe cancellation at a given frequency, you will have no idea how that frequency sounds in your mix. The same goes for a system or room that can’t facilitate low frequencies at all.
So while learning your speakers is effective, there is always a benefit to improving your speakers, acoustics, and room correction.
PART 2: Trust Your Ears
Even if you’re able to optimize your speakers and room to sound perfect with an absolutely flat frequency response, it’s important to remember why you’re actually making this music…
Your goal as the mixing or mastering engineer on a project is ultimately to create a mix that allows the listener access to the intention of the music – no matter what that might be for each particular song or album.
The problem is – as we discussed earlier – there’s no guarantee that a listener will be using a system that sounds as good as the one you’re using to mix the song. Actually, there’s a strong probability that they will be listening on a system that is much more restrictive when it comes to reproducing low and high frequencies.
A lot of musicians and mixing engineers throw in the towel and give up at this point, saying “We can’t cater to the people who don’t even care enough about the music to listen on good speakers” or “Why make a mix that sounds great on speakers when everyone is going to listen on a smartphone anyway”.
While I understand the frustration, I reject the idea that you have to choose one or the other. Most of the professional mixes that I hear sound amazing on my iLoud monitors, they sound great in my car, and if I’m listening on a smartphone I can at least experience the critical parts of the harmony and rhythm.
It doesn’t have to sound amazing on a smartphone – in fact, it can only sound so good. But so long as the listener can experience the core intention of the music, the mix is doing its job.
Here are some of the common techniques used by mixing engineers that allow them to create mixes that translate to a variety of playback systems…
First, if there are a lot of stereo elements in your mix (where the signal feeding the left speaker and right speaker are very different), you might want to try summing your mix to mono. This is often referred to as the “mono compatibility” of a mix.
For example, you probably know that panning a guitar off to the left and a piano off to the right can create less destructive interaction between those two instruments. Whereas you might need to carve out more space with EQ and compression to get the two instruments to work together directly in the center, panning them left and right can allow each instrument the space it demands with less need for processing.
The issue is that when that very wide mix is played back on a smartphone in portrait mode or through a single speaker, the guitar and piano signals will be mixed together, creating interactions that wouldn’t be heard in a stereo mix through two speakers.
I’m not saying that you shouldn’t use panning in your mix – all I’m saying is that if you do, you should at least check how it will sound in mono. This can be done by pressing the “Mono” button on your audio interface or monitor mixer. Or if your interface doesn’t have that option, you can probably find a “Mono” button within your DAW.
If the mix sounds phasey when you press the “Mono” button, or if you hear a big change in tonality and timbre of the instruments, it might be a good idea to correct those issues with EQ, compression, etc. so that nothing is lost in the event that your mix is played back in mono.
The second technique used by a lot of successful mixing engineers is to test a mix on a variety of speakers. In a high-end recording studio, you’ll often find that there are multiple pairs of speakers above the console. During the mixing process, an engineer might alternate between each pair to hone in on a particular frequency range or to ensure that the heart of the music comes across correctly, even through less-than-ideal speakers.
You’ll notice that I’ve only got one pair of speakers at my mixing position – the iLoud Precision 6s. But I’m still able to test the sound of my mixes on a variety of systems using the X-Monitor software…
When I want a sound that’s as flat and transparent as possible, I’ll use the speakers in “Precision” mode. But when I want to test the mix on different speakers, I can flip through some of the built-in speaker emulation profiles.
These profiles are made to emulate both the frequency response and the phase response of some of the most famous studio monitors on the market. I can virtually switch between speaker voicings without the need to set up a bunch of physical speakers behind my desk.
And there are even profiles for hi-fi speakers, TV speakers, a bluetooth speaker, and a smartphone. When my mix sounds great in “Precision” mode and it sounds decent on the other modes, then I know I’m finished with my mix.
You can do the same thing whether that means switching between different speakers in your studio or rendering your mix and taking it to another system to test how it sounds elsewhere.
But if a mix doesn’t translate when switching between various speaker profiles, what steps can we take to make sure the mix does translate? In the next video and blog, Mixing for Smartphones, Laptops, & Small Speakers with Saturation you’ll learn the technique that I mentioned earlier that will help you do just that.
I’ll see you there.