Low End of Your Mix Not Hitting? Here's Why😱
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The Problem with Your Low End
Is the low end of your mix weak and not hitting?
Does volume balancing and EQ not seem to fix the problem?
If all of that luscious, deep low-end that should be on your track is missing, or if it’s not as present as you’d like, there’s a good chance you’re experiencing something called phase cancellation in your mix.
In this article, I’m going to show you how to diagnose this problem, and provide some solutions that will help you fix it so you can achieve the clear, present and impactful bass sound your mix desperately needs.
What is phase cancellation?
“Phase” refers to the relationship in timing between two or more sound waves.
When multiple audio signals are combined, they can either reinforce each other (being “in-phase”) or cancel each other out (being “out-of-phase”). Whether they are in or out of phase depends entirely on the alignment and polarity of their waveforms.
“Polarity” refers to the orientation of a waveform, specifically whether it is in positive or negative alignment.
Phase cancellation represents the most severe form of phase problems encountered in audio mixing. It occurs when two sounds are out of alignment, causing them to be out of phase with each other. Consequently, these sounds cancel each other out, making them harder to hear. In some cases, when the sounds are perfectly out of phase, they may become entirely silent.
The more sounds you have competing in a set frequency range, the more likely you are to experience phase cancellation between them.
Phase alignment becomes more important with low frequencies of a mix more-so than mid and high frequencies because low frequency sounds have longer wavelengths in comparison to the shorter waveforms associated with higher frequencies.
Phase differences ultimately become more significant for longer wavelengths, as even slight phase misalignments in the low end can cause noticeable interference patterns, including cancellation.
When should you address phase issues?
Phase issues are best addressed as early as possible – ideally, before even moving into the mixing and mastering stage of a song.
My process is to first set levels so I can hear phase issues, and then correct phase issues before moving on to next steps in the mixing and mastering process.
That means before you go ahead and start adding EQ, compression and other processing to your tracks, you should address any phase issues first and foremost.
Otherwise, all of that extra processing may only exaggerate a phase issue at the foundational level of your mix and become even more problematic later.
Once you’ve addressed phase issues in the low frequency range of your mix, you should already have a more impactful and pronounced low end before doing any other processes, and that will ultimately make the rest of the mixing process easier.
How do you identify phase issues?
For our purposes focused on the low end of a mix, phase issues will typically result in your track sounding thin, weak and/or hollow, with a low end that lacks impact and presence or, worse, disappears entirely.
However, phase issues can also sound like:
- Muddiness and a lack of clarity
- Collapsed stereo image resulting in a smearing type of sound
- Interference and comb filtering
- Uneven frequency response, resulting in some frequencies being exaggerated or attenuated unnaturally
In terms of actually identifying phase issues in your mix, I approach this in two ways:
Step 1: Visually Identify Phase Issues in Your Mix
The first thing I do to identify phase issues in a mix is to take a look at two (or more) waveforms that occupy a similar frequency range in the low end.
These are typically sounds like the Kick, Bass and 808, but may also include parallel send tracks such as parallel compression and parallel distortion, or even individual instrument sounds that sit lower in the frequency range of the track I’m mixing such as a low synth.
My goal is to examine each waveform and understand how they move and develop over time in relation to one another.
I want to specifically focus on each waveform’s polarity, being positive (moving upward) or negative (moving downward).
Do each of them move in a similar pattern and direction? Are their polarities aligned?
Or are they drastically different, and at times, in completely opposite directions?
If I visually notice differences in polarity, and therefore the phase relationship between these sounds, I will then proceed to Step 2.
Step 2: Audibly Identify Phase Issues in Your Mix
After visually examining the waveforms, I will confirm my findings by listening to them and paying attention for reinforcements or cancellation.
I will listen from two vantage points:
Reference Point #1: Stereo
By stereo, I mean that your output has two channels: a left and a right.
This is typically the default way most people, including mixers, listen to music, with a left and a right channel – such as an earbud in each ear, or sitting between two speakers.
If sounds are in-phase, they should reinforce each other and sound stronger, fuller and more present as a result.
If sounds are out of phase, they should exhibit some of the symptoms I outlined previously, including sounding weaker, duller, muddier and overall less clear or potentially even not present at all.
Reference Point #2: Mono
The other way I will listen to a track to confirm phase issues is in mono mode.
By mono mode, I mean using a plugin or other device such as a monitoring station to collapse the left and right stereo signal of your mix into a single mono source.
When you sum the stereo signal of your total mix to mono, any phase cancellations or reinforcements between the left and right channels will become more noticeable, particularly in the low end where phase issues are more pronounced.
When two signals that are out of phase are summed, they will interfere with each other and potentially cancel each other out. This results in a weaker, thinner sounding signal.
Conversely, when two signals with similar phase are summed, they reinforce each other. This results in a stronger, louder and/or more present signal.
When doing this, my goal is to see if low end elements disappear or sound drastically different when the mix is played in mono. If so, it’s a sign that phase issues are present and may need to be addressed.
Alternatively, if the low end sounds becomes stronger and reinforced, it’s a sign that everything is in-phase and may not require any corrective phase treatment.
How do you correct phase issues?
Phase can be a delicate matter, so there isn’t necessarily a one-size-fits-all solution. Instead, you will need to evaluate and attempt to resolve phase problems with one of several methods. These are 4 of my go-to methods to fix phase cancellation.
Method #1: Replace Sounds
Phase issues are natural interactions between waveforms, but can often be avoided during the production and recording phases.
This ties into the old saying “garbage in, garbage out.”
A simple way to fix phase issues in your mix is to utilize sounds and samples that are more phase coherent with one another.
My general rule of thumb is that my low end sounds such as my kick and bass should be present, impactful and synergistic from the moment I bring them into a session and set their levels.
If these two sounds are not hitting from early on, chances are there is a phase-related problem that is preventing both sounds from shining. In other words, they are getting in the way of each other more than anything.
While we can use the other methods I’m about to explore to fix this problem, a good starting point is to evaluate the nature of the sounds themselves and consider replacing them with ones that are more fitting and complimentary to one another.
Method #2: Shift the phase alignment to improve coherence
If replacing sounds is not an option, the first method I’d look to explore is using a plugin to shift the phase alignment between low end sounds to improve their coherence.
I prefer to use a phase alignment plugin like Waves InPhase, however, there are many others out there.
Tools like InPhase allow you to shift the phase relationships between waveforms by adjusting the timing of one of the waveforms, making it earlier or later in timing via a built-in delay feature.
It also provides you with additional metering such as a correlation meter which informs you of how in phase the two sounds are.
With InPhase, I will select which sound I want to be the “master” so to speak – or the one that I will phase shift the other track to adhere to.
For example’s sake, let’s say I set my KICK track to be my “master” track. I would first put a sidechain output, or send on the KICK track so I can use it as a sidechain trigger elsewhere in my mix.
Next,I will put an instance of In-Phase on the opposing sound, being the BASS in this example. On that instance of the plugin, I will set the KICK to be the SIDECHAIN input.
From there, I will click on CAPTURE at the bottom of the plugin and play a moment of the track where the two sounds play simultaneously. This will then capture and display both waveforms within the plugin itself, and allow me to later correct the timing between them.
From there, I will use the DELAY function to adjust the timing of the BASS, making it slightly earlier or later than it originally was.
I can look at the waveforms of both sounds within the plugin to manually make this choice, however, I will typically look at the CORRELATION METER. My goal is to get the correlation meter as close to +1 as possible, or at least closer than I started.
Typically you won’t get a sound all the way up to exactly +1 unless the two sounds are perfect copies of each other. However, any increase can be a good thing and ultimately make your low end more impactful.
Method #3: Manually adjust the timing of tracks to ensure their waveforms coincide properly
If you don’t have a fancy plugin like InPhase, you may opt to manually align the timing of your waveforms instead.
This is much less accurate than a phase alignment plugin since you may not have access to a correlation meter or other insights that specialized plugins offer.
It’s also important to be mindful not to make a drastic move as it may alter the timing of your track in a negative way, resulting in a discombobulated low end and rhythm section that lacks its initial emphasis.
The goal of this process is to manually trim and move one of your waveforms, making its phase and polarity at a given moment more in-line with the opposing sound.
For example, I may make an incision on my KICK drum waveform to move it earlier in the arrangement to improve its phase alignment with the BASS.
Method #4: Reverse the polarity 180 degrees
Reversing the polarity of one track via a phase-invert plugin can be a quick but less precise method of addressing phase issues and phase cancellation in particular.
This feature can be found on a number of stock and premium third-party plugins, including Trims, Utilities and even EQs like the FabFilter ProQ3.
Other Common Low End Problems
ABOUT ME
5PiECE is a graduate of the Metalworks Institute of Sound & Music Production, holding a diploma with honours in Audio Production & Engineering. He interned for Noah “40” Shebib (Drake, Alicia Keys, Beyonce) at SOTA Studios. He went on to engineer at recording studios across Toronto such as DNA Recording Facility, Vespa Music Group and New Toronto Studios before setting up his own private studio and music company 5PiECE Music. He’s also an accomplished grant writer, having secured over $400,000 in grant funding for his clients to date.