Because the decibel sound pressure level scale is logarithmic, each 20 dB increase on the scale relates to a 10 times greater increase in the amplitude of the sound pressure.​

• A sound that is 10 times greater in sound pressure would equate to an increase of 20 dB SPL.​
• A sound that is 10 times greater would measure 20 dB higher​.
• A sound that is 100 times greater would measure 40 dB higher​.
• A sound that is 1000 times greater would measure 60 dB higher​.

There is a physical limit to how high in amplitude a sound can get. Because sound waves are fluctuations (compressions and rarefactions) of atmospheric pressure, the maximum sound level is related to the lowest amount of air pressure (rarefaction) that can be produced. In other words, once the rarefaction level of a sound wave reaches zero air pressure (a complete vacuum), then the sound wave can’t be any larger. At fluctuations of atmospheric pressure that produce a complete vacuum during rarefaction, the sound pressure level is 194 dB.