Should everything below 120 Hz or 175 Hz always be mono in mastering?

No. While mono low end is still a useful safety-focused technique, the transcript shows that commercial records do not always follow it rigidly. Some songs keep low frequencies mono in certain sections, some use stereo low end throughout, and others stay fully mono. The right decision depends on arrangement, monitoring, playback translation, and how the stereo information is being created.

Why do some mixers prefer mono low end in the first place?

Mono low end can improve phase stability, make vinyl and club playback safer, and keep bass energy focused in the center. It also reduces the chance that wide low-frequency content will collapse unpredictably in mono or create uneven power between channels.

How can stereo low end still work in commercial songs?

Stereo low end can work when the widening is controlled, the arrangement leaves room for it, and the mix is checked carefully for phase and translation issues. Often the stereo effect is not random; it is a deliberate production or arrangement choice that is balanced against the rest of the mix.

Why might a verse be mono in the low end while the chorus becomes stereo?

That can be a contrast decision. A narrower verse can make a chorus feel wider and more exciting. Changing the low-end width between sections is one way to create energy lift without only relying on louder levels or extra instruments.

What should you check before deciding to keep low frequencies stereo?

Check mono compatibility, phase correlation, club and headphone translation, and whether the stereo width actually improves the track or just makes the sub feel less stable. The decision should be based on measurable translation and musical benefit, not dogma.

Controversial Mastering Technique: Should You Make Everything Below 120 Hz or 175 Hz Mono?

One of the most repeated low-end rules in mixing and mastering is that everything below a certain frequency should be mono. Depending on who you ask, that crossover point might be 80 Hz, 120 Hz, 150 Hz, or even 175 Hz. The logic is familiar: low frequencies are powerful, phase-sensitive, and safer when anchored in the center.

But the transcript behind this article asks a more useful question: do modern commercial records actually follow that rule all the time? The answer is more nuanced than many engineers expect. Looking at real stems shows that mono low end is still common, but stereo low end also appears in successful releases when it serves the production.

Why Engineers Often Mono the Low End

There are legitimate reasons this advice became standard. Centered low frequencies usually translate more predictably across speakers, clubs, headphones, broadcast chains, and mono playback. They also reduce the risk of phase cancellation, uneven speaker loading, and unstable sub energy.

In mastering, folding low frequencies to mono can act like a translation safeguard. Even if the mix already feels wide and impressive on a stereo system, uncontrolled stereo information in the sub or upper bass can make the track less stable when summed or played in difficult real-world systems.

Example 1: Taylor Swift “Style” Shows Section-Dependent Low-End Width

The first stem example in the transcript is Taylor Swift’s “Style,” produced by Max Martin. The analysis applies a high cut to 120 Hz on the bass and checks the stereo field below that point.

What stands out is that the verse low end appears fully mono below 120 Hz, while the chorus becomes stereo below that same range. Then verse 2 returns to mono again. That strongly suggests the low-end width change was intentional rather than accidental.

This is an important reminder that low-end width can be used as an arrangement tool. A mono verse can create focus and stability, while a wider chorus can feel larger and more exciting without relying only on level changes.

Example 2: “Love Me Harder” Keeps Stereo Low End Throughout

The second example is Ariana Grande and The Weeknd’s “Love Me Harder.” According to the transcript, the bass below 120 Hz stays stereo from the beginning to the end of the track.

That matters because it disproves the idea that stereo low end is automatically wrong. Clearly, in some productions, engineers and producers decide the stereo low-frequency presentation helps the song more than a strict mono fold would.

Of course, that does not mean any wide sub is safe. It means a well-controlled stereo low end can survive and even thrive in a commercial release when the sound design, arrangement, and mix decisions support it.

Example 3: “California Gurls” Uses Fully Mono Bass

The third example, Katy Perry featuring Snoop Dogg’s “California Gurls,” goes the other direction. In this track, the bass is described as fully mono.

This reinforces the real conclusion: both approaches exist in successful records. Some songs benefit from a centered low end. Some use stereo low end for width or excitement. The decision is not universal; it is contextual.

So Is Mono Low End Outdated?

No. Mono low end is still valid, useful, and often the safest option. What is outdated is treating it as an unquestionable law rather than a decision.

The transcript’s strongest point is not that stereo low end is always better. It is that modern hit records show multiple workable strategies. That means engineers should stop relying on blanket rules and start evaluating whether the stereo information below 120 Hz or 175 Hz actually helps the song and still translates well.

When Stereo Low End Can Help

Stereo low end can create contrast between sections, increase size, and make a production feel more immersive. It can also interact beautifully with modern synth basses, layered textures, and arrangement-driven width choices.

But there is a difference between deliberate stereo bass design and careless phase spread. If you want stereo low end to work, you need to verify it in mono, inspect phase correlation, listen on small speakers and headphones, and judge whether the width is genuinely improving the emotional effect of the record.

A Practical Decision Framework

Check whether the low end is stable and powerful in mono before chasing width.
Use section-by-section listening rather than assuming the entire song should behave the same way.
Inspect the stereo field below your chosen crossover point with an analyzer, not just your ears.
Compare the record on speakers, headphones, and mono playback before making a final mastering decision.
If the stereo low end creates excitement without harming translation, it may be worth keeping.
If it weakens focus, center energy, or mono compatibility, folding it to mono is probably the better move.

Frequently Asked Questions

Is 120 Hz the correct cutoff for mono low end?

Not universally. It is a common reference point, but the ideal cutoff depends on the arrangement, the bass source, the kick, the playback target, and how the stereo information is created.

Why would a chorus have stereo low end if the verse is mono?

Because width is a musical contrast tool. Making the chorus wider in the low end can make it feel larger and more impactful relative to a tighter, more centered verse.

Does stereo low end automatically cause phase problems?

Not automatically, but it increases the need for careful checking. Some stereo low-end designs are controlled and translate well, while others collapse badly in mono or feel unstable on large systems.

Should mastering always fix stereo low end from the mix?

Not necessarily. If the mix already translates well and the stereo bass is part of the production identity, folding it to mono in mastering could remove intentional impact. The job is to evaluate translation, not enforce a rule blindly.

What matters more than the mono-versus-stereo rule?

Translation. If the low end feels powerful, stable, and musical across playback systems while preserving the song’s intent, then the technique is working. If not, the rule may need to be applied more strictly.

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