Product listings for treadmills, rowers and bikes sometimes quote a noise level in decibels, and buyers naturally treat a lower number as a quieter machine. That is broadly true, but the decibel scale behaves in ways that make small numerical gaps bigger than they look and make some claims impossible to compare. This article draws on guidance from the US National Institute on Deafness and Other Communication Disorders (NIDCD), Great Britain’s Health and Safety Executive (HSE) and the US National Institute for Occupational Safety and Health (NIOSH) to explain what a dB figure means. The physics is the same everywhere, but the sources are American and British, and the article does not cover the law on neighbour noise.
Why the scale is not linear
The NIDCD explains that the decibel scale is logarithmic, which it says better represents how changes in sound intensity feel to our ears. Adding 10 decibels makes a sound ten times more intense and, according to the NIDCD, it will seem about twice as loud. The HSE makes a related point in its noise guidance, noting that because decibels work on a logarithmic scale, a 3 dB increase will double the noise.
These two statements describe different things, sound energy and perceived loudness, and they are consistent. For a buyer the practical message is that a machine advertised at 65 dB is not “a bit louder” than one advertised at 60 dB in the way that 65 miles is a little further than 60. The gap is meaningful, and a claim of a difference of a few decibels is worth taking seriously, provided the two figures were measured the same way.
What “dB(A)” means
You will often see the figure written as dB(A) or dBA. The NIDCD says A-weighted decibels differ from standard measurements because the dBA scale is based on both intensity and how the human ear responds. The HSE says an A-weighting is used to measure average noise levels, while a C-weighting, dB(C), is used to measure peak, impact or explosive noises.
That distinction matters for equipment. A listing quoting a single dB(A) figure is describing an average level. The HSE’s description of C-weighting for peak and impact noises suggests why a steady average figure is not designed to describe a sudden impact, such as a weight being set down. A machine described as quiet in average terms can still produce impacts that a headline figure does not capture, so check the listing for what was actually measured.
What the numbers sound like
The NIDCD gives everyday reference points in dBA: whispering is about 30 dBA, normal conversation 60 to 70 dBA, headphones and sporting events 94 to 110 dBA, and a jet taking off 140 dBA. These help put a claim in context: a figure in the range of conversation is not silent, and a figure well above it is not something you would ignore in a shared flat. The same source says sound can damage hearing at 85 dBA over eight hours or more, at 100 dBA for 14 minutes or more and at 110 dBA for two minutes or more. Those are hearing-risk thresholds from a US institute rather than a benchmark for domestic comfort.
Questions to ask about any noise claim
- Is the unit stated? Look for dB(A) rather than an unspecified dB.
- Is there a stated measuring method? The sources read do not set out how equipment manufacturers should measure noise, so a listing that says nothing about how, where or at what setting the figure was measured cannot be compared reliably with another.
- At what speed or resistance? A figure for a walking pace or the lowest resistance setting does not describe use at the top of the range.
- Which noise is being described? Motor hum, belt noise, resistance mechanism and impact are different things, and one figure cannot describe them all.
- Is it the same model? Figures taken from a different model or room do not transfer.
Measuring it yourself
If you can hear a machine in a showroom, you can also measure it, but the tool matters. NIOSH says its Sound Level Meter app for iOS is accurate within plus or minus 2 dBA when tested with a calibrated external microphone, and that it meets Type 2 requirements of the IEC 61672 sound level meter standard, having been tested in a reverberant chamber at its acoustics laboratory. It is available only on iOS devices because NIOSH says Android’s hardware is fragmented among many manufacturers with different requirements, and so laboratory verification of Android apps’ accuracy is not currently possible. NIOSH therefore cannot verify the accuracy of Android-based sound measurement applications.
Two cautions follow. A phone measurement made without the external microphone that NIOSH used in its testing may not match the stated accuracy, and any reading is only meaningful if you note the position, the machine setting and the room, so that you can repeat it. Treat a phone reading as a rough comparison between machines in the same room, not as a certified value.
Connecting the figure to your home
A decibel figure is one input. Whether a machine is acceptable in your home depends on the room, the time of day and who else lives nearby. Our guides on treadmill noise and vibration in upstairs rooms and exercise bike noise and resistance faults look at those wider questions.
The bottom line
The decibel scale is logarithmic: 3 dB doubles sound energy according to the HSE, and 10 dB is ten times the intensity and seems about twice as loud according to the NIDCD. A dB(A) figure describes an average level, not necessarily an impact, and it is only comparable between machines when the unit, speed and measuring method match. Treat unexplained noise claims cautiously, and if you measure for yourself, remember that NIOSH can verify its iOS app’s accuracy but not Android apps.