What the infrasound experiment found
Scatterty and colleagues exposed 36 adults to calming or unsettling music, with or without approximately 18 Hz infrasound at 75–78 dB. Exposure lasted less than five minutes. Infrasound was associated with higher salivary cortisol and more negative responses on selected mood measures, although participants could not reliably identify its presence.
Evidence strength is preliminary: there were nine people per condition, one frequency range and a brief laboratory exposure. Participants were awake, and sleep was not measured.
Keep the conclusion narrow
This result challenges the assumption that inaudible low-frequency exposure must be relaxing. It does not show that all bass, brown noise or quiet ambient audio is harmful. An ordinary recording played through a phone is not necessarily reproducing the experimental exposure. The study also cannot establish what happens after someone falls asleep.
Do not confuse different frequency claims
A description of low-pitched sound is not the same thing as a claim about brain activity. A track can contain audible bass without proving an effect on sleep stages. Likewise, a label such as 'delta' does not tell you whether a particular recording has been tested in sleeping listeners.
The useful question is what the producer is actually describing: musical character, a technical audio setting, or a measured health outcome? Those categories should remain separate. A number can be technically accurate while the benefit advertised beside it is unsupported.
A production lesson, not a treatment formula
For MindTuned, the conservative design inference is to avoid adding extreme low-frequency energy solely because it sounds impressive in a description. Make decisions by the intended listening experience and by checking the audio, not by assuming that inaudible content has a hidden restorative purpose.
That is not a recommendation to remove the warmth from every mix. Nor does one experiment establish a universal filtering threshold. Quality control should preserve the musical intention while checking for unwanted rumble, distortion and abrupt changes on the playback systems people actually use.
Choose depth by comfort
A deeper-sounding texture may be exactly what you enjoy. Preview it before bed rather than turning the level up to feel a promised effect. If it feels oppressive, distracting or uncomfortable, reduce it, try a different texture or stop. You do not need to compensate for what a small speaker cannot reproduce.
In MindTuned Sleep Studio, different noise colours and independently adjustable layers provide listening choices. Choose by preference at a comfortable level. Selecting brown noise should not be treated as a clinical decision or as a way to obtain a particular brainwave state.
What to ask of a frequency-based promise
Look for a study of the actual intervention, a clearly described comparison and an outcome that matches the promise. Research on a short waking exposure cannot establish overnight sleep benefits, just as a preference rating cannot demonstrate disease treatment.
The takeaway is balance. This preliminary experiment is a caution against 'lower is always better,' not a warning to avoid every low sound. Keep the listening experience optional and the explanation accurate. Warmth and depth can be musical qualities without becoming medical claims.
Research cited
This article is for general education and is not medical advice.