It is the guaranteed sound power level: the acoustic power the machine radiates, which the manufacturer undertakes not to exceed. It is required by law on outdoor equipment, and it is the most reliable comparable figure on this shelf.
Why it exists
The outdoor noise directive requires machines used outdoors to carry it, legibly and indelibly, and to state it in their documentation. That obligation is why the figure turns up in catalogue listings at all — without it, nobody would publish a noise number.
Why it is a guarantee and not a measurement
A measurement has an uncertainty, and a production run has a spread. If the marked figure were a single measured value, half the machines off the line would exceed it.
So the manufacturer measures under a defined method, adds an allowance for both, rounds up, and marks the result. That is why the shelf is full of even integers and why no machine is marked 94.3.
The measured value is lower than the marked one, and it is rarely published.
What it lets you compare
Two machines of the same kind, directly. Sound power does not depend on where you stand, which is exactly why it was chosen for a marking — it is a property of the source.
Across machine kinds it is still comparable as radiated power, though what that feels like differs: a shredder and a mower radiating the same power do not sound alike.
What the figure does not tell you
The loudness at your ear, on your terrace, or over a fence. That is a sound pressure level and it depends on distance and surroundings.
The character of the noise. A-weighting flattens the difference between a whine and a rumble.
Anything about the hours you may run the machine, which is a local rule and not this directive.
How this site handles it
Machine pages here print the guaranteed level with the quantity named. Where a listing prints a lower number that is clearly an operator-position figure, the page names that quantity instead. Where nothing identifies which is which, the page says so — and on this shelf that is common enough to be worth a line.
Wherever this page and the maker’s own documentation disagree, the documentation wins. Every cutting width, cutting height, stated area, pack capacity, flow rate, head, sound level and application rate on this page comes from the maker’s own published figures, with the unit as printed and the source named. None of it is measured here, and no figure is converted into another convention, because a converted number is a different number. And the pair of quantities this page will not merge: a guaranteed sound power level is not the loudness at your ear. The figure in the oval on the housing describes what the machine radiates and is a guarantee rather than a measurement; the figure in the manual describes a pressure at a position. Both are printed as decibels. This page names which one it is reporting, and says so when the listing does not.
The questions that keep coming in
Why is it always an even number?
Because it is a guarantee, arrived at by measuring, adding the uncertainty of the method and the spread of production, and rounding up. A machine measured at 94.3 is commonly marked 96.
Can I compare the oval figure with the one in the manual?
No. They are two different quantities — sound power on the housing, sound pressure at the operator’s position in the manual — and the gap between them on the same machine is often well over ten decibels.
Last reviewed 26 September 2026