What is a Sound Level Meter?

A sound level meter is a handheld instrument used to measure sound, or noise. And what is noise? Well, that's sound that you, or somebody else, does not want to hear!

Sound level meters come in various shapes and forms, but they have common points. They tend to have a pointy bit at the top to stop the sound reflecting back at the microphone. Some lower cost sound level meters do not have a pointed top but instead have the microphone on an extension to get it away from the case, again to reduce reflection. This method is used to keep the case design cost down.

The sound level meter picks up the small variations in pressure that are the sound waves and, after passing it through amplifiers, filters, etc. provides you with a reading in decibels.

Please also refer to our notes on sound level calibrators.

Analog or Digital?

Sound level meters are usually digital these days, although there are some analog units of older designs still available. If you need an analog meter then please email as we still have some older models available. With the lower cost units for simple measurements, many find the analog sound level meter to be easier to use: you can see by eye the variations in level and average it out yourself. More expensive instruments tend to be "integrating", which does this job for you. Digital displays also allow a wider span to be shown whilst still giving the necessary 0.1 dB resolution. It is difficult to show 100 dB span to 0.1 dB resolution on an analog display small enough to fit in your hand. It's easier (and cheaper) to do it digitally.

Which "Type" of Sound Level Meter

Sound level meters are available in various Types or Grades, as defined by the standards IEC 60651, IEC 60804 and ANSI S1.4. This is not the place to go into serious detail about the definitions of the grades (that is explained in clear terms, maybe, in the standards themselves) other than to say that a Type 1 instrument is more accurate than a Type 2.

The grade of sound level meter you choose will usually be defined by the regulations you need to meet. Most regulations for occupational noise measurement (noise at work) require the use of Type 2 sound level meters. In this case there is no need to go to the extra expense of the Type 1. One or two countries do specify Type 1, so do check first.

Many environmental (measuring outside in the environment) noise regulations require the use of a Type 1 sound level meter. Type 1 instruments also tend to measure down to lower noise levels (limited by the cheaper microphone on the Type 2), making them more suitable to the lower levels you tend to get out in the environment. See our environmental sound level meters.

Cheap Sound Level Meter - No Type?

Cheap sound level meters that are any use are hard to come by. The reason is simple: it costs a lot to make a sound level meter that meets the standards. We would not recommend using such a meter for any type of noise measurements. With a "low cost" Type 2 instrument you know that you are measuring the noise with something that has been designed to a certain standard and that the levels measured will be comparable with those made by a similar meter.

It is not worth being tempted by a meter that does not meet the standards, especially if the noise measurements are to be used for legal purposes.