# How do "decibels" work (in an easily, layman's understandable way)?

**URL:** <https://boards.straightdope.com/t/how-do-decibels-work-in-an-easily-laymans-understandable-way/1033031>\
**Category:** Factual Questions\
**Tags:** science-math\
**Created:** [September 13, 2026, 9:03am UTC](https://boards.straightdope.com/t/how-do-decibels-work-in-an-easily-laymans-understandable-way/1033031 "2026-09-13T09:03:03Z")\
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**Post date:** [September 14, 2026, 2:40pm UTC](https://boards.straightdope.com/t/how-do-decibels-work-in-an-easily-laymans-understandable-way/1033031/18 "2026-09-14T14:40:37Z")

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> [@Crafter\_Man](#):
>
> Here is the horsepower to dB mapping for the power outputs of six engines:

So, dumb question here (I never understood much math or physics):

What does it mean to say that horsepower = decibel? (Or, for that matter, 1 W = 30 dB)?

I’m confused about the three uses of dB here:

1. As a “volume” to the layperson
2. As a ratio between two measurements of power (?)
3. As a measurement of power itself (?)

What does it mean to say that a certain power output is also a certain volume…? Like wouldn’t a 100W bulb “sound pretty different” than a 100W vacuum cleaner, the same distance away? Is there some secret connection between heat and what we hear as sound waves…?

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