The d b calculator turns distance, reference intensity, reference pressure, sil (sound intensity level), spl (sound pressure level) into sound wave pressure, intensity of sound. It suits students checking a worked example, professionals sanity-checking a figure, and anyone who wants to see how the pieces of the calculation fit together.
What Is the D B Calculator?
It is built around sound wave pressure, intensity of sound, and it works the same way whether you are checking a homework answer, confirming a colleague's figure, or working something out for yourself. Everything runs in your browser, so nothing you enter is uploaded anywhere.
How the D B Calculation Works
The steps are applied in order, so an output that depends on another output updates as soon as the underlying figures change.
The relationship between distance, reference intensity, reference pressure, sil (sound intensity level), spl (sound pressure level) and sound wave pressure, intensity of sound is fixed, so the same figures always give the same answer. That makes it a good cross-check: run the numbers a second way and see whether the result agrees.
Getting a Result You Can Trust
The most common mistake is mixing units. Keep distance and reference intensity and reference pressure and sil (sound intensity level) and spl (sound pressure level) in the same system throughout, and make sure any rates or ratios are quoted per the same period. When a result looks far out of range, the units are nearly always the reason.
Frequently Asked Questions
What do I need to work out sound wave pressure?
Enter distance, reference intensity, reference pressure, sil (sound intensity level), spl (sound pressure level). The calculator then works through the relationship and reports sound wave pressure, intensity of sound.
What does the d b actually calculate?
It takes distance and reference intensity and reference pressure and sil (sound intensity level) and spl (sound pressure level) and converts them into sound wave pressure, intensity of sound using the standard relationship for this problem. Each step is applied in turn, so every output is traceable back to the numbers you typed in.
How should I enter distance?
Use the value you actually have, in the unit shown next to the field. Enter every value in the same unit system. The calculator assumes the figures you supply are consistent, so it cannot correct a mistake that happens before the calculation starts.
Why does a small change in one value move the answer so much?
That happens when an output depends on a ratio, because dividing by a small number magnifies any change in it. Check the units first, then check whether the value you entered is in the range the relationship was designed for.
Can I use this for a quick estimate as well as a precise answer?
Yes. The calculator is built for quick checks, so round your inputs to a sensible number of significant figures and the result will be just as useful. If you need more precision, keep the same method and add digits to the inputs rather than adjusting the method itself.