What is the difference between the static range and dynamic range of the sound level meter
The linear range is the core technical parameter of the sound level meter, and this technical index represents the technological advancement of the product to some extent. But we often see that some manufacturers write linear range (measurement range), and some manufacturers give dynamic range. What is the difference between them?
First of all, let's take a look at their definitions. In order to make most people understand, we describe them in the most popular language, which may not be rigorous enough, but it does not affect understanding.
Dynamic Range
The difference between the maximum and minimum values displayed by the sound level meter, professionally expressed as the difference between the overload sound pressure level and the equivalent noise sound pressure level (self-generated noise), is the dynamic range. For example, if the dynamic range is 15 dB to 130 dB, it means that the local noise of the sound level meter is around 15 dB, and the measurement upper limit is 130 dB. It should be noted that the sound pressure level tested in the dynamic range cannot be guaranteed to be accurate, so strictly speaking, it is not recommended to use the dynamic range to express the sound level meter, which will mislead the user, especially when measuring with low noise, the error is particularly large. big.
Note: (1) Self-generated noise (intrinsic noise, local noise): When there is no signal input, the noise displayed by the sound level meter can be called by the above three names. The difference in English translation is now standardly self-generated noise.
(2) Self-generated electrical noise
When there is no signal input, the residual noise in the instrument circuit (excluding sensors) is lower than the self-generated noise. The manufacturer will test this indicator to evaluate the performance of the circuit, and the instrument user does not need to pay attention to this indicator.
(3) Self-generated noise is a reference index, not a basis for judging whether the instrument is qualified or not, and the final level of linearity shall prevail.
Linear range (also called measurement range in general)
The range that the sound level meter can accurately measure, such as the linear range of 20 dB to 130 dB, means that the sound pressure level measured in this range is accurate and reliable. Its professional definition is that in any level range and specified frequency, the deviation of the level range of the sound level meter does not exceed the sound level range of the acceptance limit specified in IEC61672-1:2013. (Level 1 sound level meter full-scale tolerance is ±0.8 dB, level 2 sound level meter is ±1.1 dB. When the signal change is within 10 dB, the tolerance of level 1 sound level meter is ±0.3 dB, and level 2 sound level meter is ±0.3 dB. Calculated as ±0.5 dB.)
Difference Between Linear Range and Dynamic Range
It can be seen from the definition that there is no tolerance requirement for the dynamic range, but there is a tolerance requirement for the linear range. Generally speaking, the upper limit of their measurement is the same, but the lower limit is different. For a level 1 sound level meter, the measurement lower limit of the linear range ≈ the lower limit of the dynamic range +11. For example, if the dynamic range of a level 1 sound level meter is 20 dB to 130 dB, its linear range is 31 dB to 130 dB. Because when the noise of the machine is 20 dB, the influence on the 31 dB signal is 0.3 dB, that is, when the standard signal is 31 dB, the indication value of the sound level meter is 31.3 dB, with a deviation of 0.3 dB, which just meets the requirements of a class 1 sound level meter.
