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If you are looking for a low-noise compressor, you compare the decibels on the data sheets. But decibels can refer to two different quantities, and the measurement conditions are often missing.

LpA and LwA

• Sound pressure level LpA: what you hear at one point, at a certain distance. It depends on the distance and on the surroundings: without the distance the number says little.
• Sound power level LwA: how much sound energy the machine emits, independent of distance. It is the higher number. For the Einhell TC-AC 190/24/8, for example, the data sheet gives 97 dB(A) sound power and 75 dB(A) sound pressure [2].

In the table we report only the sound pressure level LpA, so as not to mix the two quantities.

Measurement conditions

• Some Einhell manuals declare the measurement to EN ISO 3744 [11][13][15].
• Fini gives the sound pressure of the Siltek measured at 7 metres [26].
• For the other models in the table we found neither the distance nor the standard.

Two values measured at different distances cannot be compared: a compressor declared as quieter may simply have been measured further away.

Silent models and delivered air

In the table, the delivered air of silent models is in a similar range to that of standard models of the same size: quietness says nothing about the air. Check that it is enough for your tool in the calculator.