It's a power ratio. 1dB always means a power ratio of 1.26. That might mean a voltage or current ratio, say, of 1.12, but that is because the relationship between voltage ratios and power ratios is a simple square.

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arghwhat a year ago | parent | next [-]

The problem isn't really the ratio, but the use in arbitrary contexts that require a lot of pre-existing knowledge. The reference value is sometimes a rather arbitrary value in an arbitrary unit, neither of which is communicated by the "dB" unit suffix.

The SI way to write `10 dBm` is to write `10 dB (1mW)`, clearly communicating both the power level and the reference point and unit. This ensures that you do not have to just memorize a bunch of decibell suffixes and their magical reference values.

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twelvechairs a year ago | parent | prev | next [-]

The other side of the authors discussion is the use of 'decibels' to describe 'loudness'. The big difficulty there is that 'loudness' is a sense perception that varies between people and in different contexts. The article touches on this 'weighted to mimic human hearing...' but doesnt mention the systems to do this - DB(A) and others, none of which achieve scientific perfection.

Our senses are all like this - for the same reason we have dozens of systems to describe color. And why perfume and wine makers can never agree descriptions.

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lxgr a year ago | parent | prev | next [-]

That’s maybe what it “is”, but not the only thing people use it for in many fields. Very often, it’s a ratio between a measured quantity and some (implied) base unit of the same quantity.

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hgomersall a year ago | parent [-]

In which case they're misusing it, which is hardly a problem with the notation.

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lxgr a year ago | parent [-]

As I read it, the criticism of TFA is directed at how people actually use the notation, not how it ought to be used in an ideal universe.

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hgomersall a year ago | parent [-]

But people misuse words and notation all the time without anyone arguing they're ridiculous. I use dBs on a daily basis with plenty of other people and never have any trouble. Indeed, we'd struggle if we had to use something else.

	▲	lxgr a year ago \| parent [-]
		> But people misuse words and notation all the time without anyone arguing they're ridiculous. That only indicates that you haven't found the many angry blog posts yet, not that they don't exist :)

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weinzierl a year ago | parent | prev | next [-]

I understand that and it just reinforces my point. What 1 dB essentially means is highly dependent on a most of the time silent context.

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hgomersall a year ago | parent [-]

No, it always means a power ratio. That sometimes can imply something else, but that's on you to work that out.

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lxgr a year ago | parent [-]

Yes, but that, i.e. putting the burden of disambiguating some meaning from context on the receiver instead of the sender, is just bad communication.

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hgomersall a year ago | parent [-]

What? Blaming a bad communicator for bad communication is fine. Blaming their words because they used them badly is not.

	▲	lxgr a year ago \| parent [-]
		What about blaming a common but confusing usage of some words pervasive in some fields?

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klodolph a year ago | parent | prev [-]

Exactly. I’ve never seen it otherwise.