The 30Hz Question: Why Producers Still Argue About Rolling Off the Ultra-Low End

Should you roll off your productions at 30Hz?

The debate goes like this: frequencies below 30Hz are mostly rumble and noise that waste headroom and muddy your mix. Cut them out, clean things up, and your track will sound tighter and louder. 

Some cut the ultra-low-end ritualistically. Others think it's outdated advice that ruins a perfectly good low-end. Both sides have valid points, which is why the debate keeps going.

However, it’s rarely so simple as a binary choice. There are few one-size-fits-all rules in music production. 

Indeed, there are also sacrifices to cutting any frequency without prejudice.

So really, this is a rule that should be approached with more nuance than it usually is.

Let’s explore the 30Hz debate in detail and how to think about the ultra-low portion of your tracks. 

• The 30Hz Debate: Where It Started and Where We Are Now
• Modern Technology Changes the Game
• The Risks of Cutting at 30Hz
• Going Deeper: The Territory Below 30Hz
• The 19Hz Discovery
• The Psychology of Inaudible Sound
• There’s More to Bass Than Many Assume

The 30Hz Debate: Where It Started and Where We Are Now

The audible frequency spectrum runs from roughly 20Hz to 20KHz – at least in theory. 

In practice, few people can hear the full 20-20 spectrum. Moreover, sounds in the mids and mid-highs are perceived much louder than others, purely because our ears have evolved to accentuate these frequencies. 

Why? Because most sounds in nature – including the human voice – occur in this range. 

If you look at the Fletcher-Munson curve, you’ll see how sounds at the extreme ends of the spectrum need considerably more energy (sound pressure) to create equal volume.

Employing a 30Hz high-pass filter became standard practice for good reasons.

Vinyl records couldn't handle ultra-low frequencies without causing playback problems – stylus needles would skip, cutting engineers couldn't fit as much content on each side, and the physics of analog recording became complicated at this depth. 

Then, most consumer speakers roll off around 40Hz anyway. Even many decent commercial subs can’t do 30Hz and below particularly well.

And added to all that, the human ear is really poor at sensing bass this low. 

Thus, cutting tracks at 30Hz has become a benchmark for so long because it solved many real problems with minimal downsides. 

By doing so, you can free your sub from a muddy, imprecise low-end and bring focus to the audible frequencies the human ear is much better at sensing. 

Modern Technology Changes the Game

While there are still some limitations, today's equipment has changed dramatically since the 30Hz rule was established:

• Professional audio systems designed for live venues can now reproduce frequencies as low as 16Hz with clean output. Club sound systems are built specifically to deliver massive impact in the ultra-low range, and modern subwoofers handle these depths without the distortion and phase issues that plagued older designs.
• Digital audio systems no longer waste headroom on ultra-low content the way early converters did. Modern A/D conversion maintains full dynamic range across the entire spectrum, and processing power limitations have become irrelevant.
• Studio monitoring has improved significantly. High-quality subwoofers and room correction systems mean producers can actually hear what they're working with in the ultra-low range.

The creative possibilities have expanded in step, with sound design evolving to offer more to producers working creatively with the low end. 

The Risks of Cutting at 30Hz

The traditional advice to roll off at 30Hz isn't as straightforward as it seems.

While it can solve some problems, it can create others – and modern producers need to understand both sides of the equation.

Applying this rule without sufficient thought and consideration could damage your mixes.

Understanding Fundamental Frequencies

One of the most important factors in the 30Hz decision involves understanding where your kick drums and bass instruments live frequency-wise.

The textbook numbers don't always match what happens in practice, and cutting at 30Hz can accidentally remove musical content you didn't know was there.

Kick drum fundamentals vary widely:

• Large acoustic kicks: often 30–50Hz
• Standard rock/pop kicks: typically 40–60Hz
• Electronic/synthetic kicks: can be 25–45Hz
• 808-style drums: often 25–35Hz, sometimes lower

Bass instrument fundamentals:

• Electric bass guitar low E = 41Hz, with harmonics extending lower
• Upright bass can reach similar depths with different tonal characteristics
• Synth bass routinely works in the 20–35Hz range
• Sub-bass patches often target specific frequencies below 30Hz

The fundamental frequency represents the core pitch of each instrument – remove it and you change the character completely. 

Phase Issues and Peak Level Problems

Filters don't behave the way many producers expect them to, especially when it comes to phase relationships and peak levels.

• Minimum phase EQs (the standard type found in most plugins and hardware) introduce phase shifts that can actually increase peak levels, even when you're cutting frequencies. 
• Phase shift effects extend upward: A high-pass filter set at 30Hz doesn't only affect frequencies below 30Hz – the phase shifts can influence frequencies well above the cutoff point. This can cause unexpected interactions between kick drums and bass instruments, making the low end feel uneven or unstable.
• Linear phase EQs solve some problems but create others: Linear phase filters avoid the peak level increases and phase shift issues of minimum phase designs, but they introduce pre-ringing artifacts – a kind of "reverse echo" that can smear transients and make kick drums feel less punchy. 

The practical upshot is that if you're going to high-pass at 30Hz, you need to understand what type of filter you're using and how it behaves. 

Standard stock EQs in most DAWs are minimum phase designs that can cause the problems described above. 

If you're experiencing weird phase issues or unexpected peak level increases after high-pass filtering, try switching to a high-quality linear phase EQ – but be aware that you're trading one set of compromises for another.

Going Deeper: The Territory Below 30Hz

As you move below 30Hz, sound becomes progressively harder to perceive. Our ears become less sensitive to these frequencies, and the line between what we hear and what we feel starts to blur.

Around 20Hz marks the generally accepted threshold of human hearing. Below that point, we enter the realm of infrasound – frequencies that can be felt but not consciously heard, yet still affect us in surprising ways.

However, even though we cannot hear frequencies this low, they don’t totally escape our senses. 

The story behind infrasound and its impact on our psychological state starts with Vic Tandy, a British engineer working in a medical equipment lab during the 1980s. 

The facility had gained a reputation for being haunted, with staff reporting strange experiences and a general sense of unease. Tandy, being scientifically minded, dismissed these claims as suggestion and imagination.

…until he experienced something himself that changed his perspective entirely.

Working alone one evening, Tandy felt overwhelming anxiety and the distinct sensation of being watched. The hair on his neck stood up. He saw a gray figure in his peripheral vision that vanished when he turned to look directly at it. 

Thoroughly unsettled and unable to concentrate, he left for the night, wondering if the ghost stories might have some basis in truth.

The 19Hz Discovery

The next day, while working on his fencing equipment, Tandy noticed something that sparked his curiosity.

A sword blade clamped in a vice was vibrating intensely, even though nothing was touching it. The vibration was so strong he could see it clearly, and it seemed to have no obvious source.

What he discovered changed how we understand "inaudible" frequencies and their effects on human perception. 

A newly installed exhaust fan was creating a standing wave at 18.98Hz – below human hearing range. This frequency happens to be close to the resonant frequency of the human eyeball, causing optical distortions that make objects in peripheral vision appear larger and more threatening.

The infrasound was also triggering a cascade of physiological responses: anxiety, unease, cold sensations, difficulty concentrating, and the feeling of an unseen presence. Tandy had found a scientific explanation for the lab's "haunting." 

The ghost was real – it was a sound wave!

He didn't stop there. Tandy investigated other allegedly supernatural locations and consistently found elevated infrasound levels caused by machinery, structural resonances, or environmental factors. 

His research suggested that many ghost sightings could be explained by sound waves we can't consciously hear but that our bodies respond to anyway.

Some natural infrasound sources include:

• Earthquakes and severe weather systems
• Ocean waves and atmospheric disturbances
• Wind patterns and geological activity
• Large-scale environmental phenomena

Artificial infrasound sources:

• Industrial machinery and HVAC systems
• Building resonances and structural vibrations
• Large speaker systems and audio equipment
• Transportation systems and urban infrastructure

Animals have been using infrasound for millions of years. Elephants communicate across vast distances with infrasonic calls that can travel for miles through solid ground. 

Tigers emit 18Hz frequencies before attacking, possibly to freeze prey through fear responses.

Whales, hippos, and other large mammals employ these frequencies for long-distance communication that works far better than higher frequencies.

In essence, the world around us is much louder and more cacophonous than our ears can detect.

The Psychology of Inaudible Sound

What makes infrasound so intriguing is its ability to affect human psychology and physiology without us being consciously aware. We might not hear a 19Hz tone, but our bodies definitely respond to it.

Research has shown that exposure to infrasound can cause:

• Feelings of unease and anxiety
• Visual disturbances and hallucinations
• Physical discomfort and nausea
• Difficulty concentrating
• Sense of presence or being watched

Film sound designers cottoned on to infrasound and started using it deliberately.

French film producer Gaspar Noé openly used 27Hz tones in his brutal and disturbing film "Irreversible," explaining to interviewers: "You can't hear it, but it makes you shake. In a good theater with a subwoofer, you may be more scared by the sound than by what's happening on the screen."

Today, ultra-low bass and infrasound are key in film scoring, with major soundtracks to films like Interstellar featuring very low bass content. 

Now, whether infrasound has legitimate use in non-cinematic music is a different matter. It definitely assumes high sound pressure to work as intended, the kind of which you might find in a cinema. 

But infrasound is, nevertheless, evidence that sound beyond the boundaries of the human ear does not simply disappear.

There is More to Bass Than Many Assume

It’s tempting to treat bass as this monolithic entity, a brute that simply needs to be fat and subby. But really, there’s a lot more to bass than what meets the eye. 

The ghost frequency that haunted Vic Tandy's laboratory sits at 19Hz – well below the traditional cutoff point, yet its effects influence everything we perceive above it. Whether you're producing hip-hop beats or film scores, those barely audible frequencies might be more important than you realize.

The best guideline is to understand what you're working with and make decisions that serve your specific project. 

Sometimes preserving ultra-low content enhances your music's impact and emotional resonance, adding weight and presence that can't be achieved any other way. 

Sometimes clearing it out creates space for more important elements and improves overall clarity.

Make the decision that serves your music. Sometimes that means embracing those ghost frequencies in your music. Sometimes it means exorcising them entirely.

Whatever you do, Sample Focus has the samples you need to produce fat, full bass.

So browse the collection and fuel up your sample collection today. 

Happy producing!