281–290 of 511 posts
Earlier quoted context omitted.
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.
In which case they're misusing it, which is hardly a problem with the notation.
Earlier quoted context omitted.
It makes perfect sense that the sliders start at 0dB and go down to -inf. Maybe you don't understand it, but it definitely makes sense. Everyone who uses dB has also tried a % scale with 100% as 0dB, and then later made a conscious choice to figure out how dB work. Maybe they're all in a conspiracy to make things needlessly complex. But that's not the only possibility.
> and then later made a conscious choice to figure out how dB work. You're just projecting your ideas here. I've not made that choice, it's just the only option in a lot of software - I'd like my % slider back.
They are still some kind of faux-logarithmic*
*behavior depends on drivers/hardware.**
**for some hardware 50 in Windows will be neutral and 100 will be something like a +30 dB digital gain, that's probably in part because Windows is mapping the 0-100 range in some way to the USB audio control range, which is at most +-127 dB or something like that.***
***with some audio interfaces (the non-USB-Audio-class kind) the 0-100 actually becomes a linear factor of 0-1, making the windows controls very useless indeed, as 70% of the slider range does approximately nothing.
It's a bit like hating numbers, and saying "What do you mean by 'three'; what is it - three volts, three amps, three metres? Clearly 'three' is meaningless, and we should stop using it and all the other numbers besides." decibels are simply a dimensionless ratio, used as a multiplier for some known value of some known quantity. In every context where decibels are used, either the unit they qualify is explicitly speci…
Interviewer: "So what's the fastest you've gone on your bike?" Kid: "Thirty." Interviewer" "Thirty what?" Kid: "Umm..." Kid: "Speed." [0] https://www.youtube.com/watch?v=OYt1kqDNlMY
"Plain" decibels are simply (power) ratios. These can describe multiplicative changes in power. These are positive for gains (like in a power amplifier) or negative for attenuations (like path loss). They are unitless quantities.
Decibels add. A ten 10 dB gain (x10) followed by a 20 dB loss (x0.01) is -10 dB (x0.1).
"Flavored" decibels are in reference to some power quantity. For example, dBm uses one milliwatt as its reference. So 2 mW / 1 mW = 2 = 10^(3/10) = 3 dBm. These quantities have associated units, but they're still technically dimensionless.
Here's the key insight. You can only have one "flavored" decibel value per computation. Say you have some 3 dBm signal (2 mW). You can add as many regular decibel values as you want, but the unit is still dBm. 3dBm + 4 dB - 7 dB = 0 dBm. In linear units, 2 mW * 2.5 * 0.2 = 1 mW
If you were to do something like 3 dBm + 0 dBm, the linear units would be 2 mW * 1 mW = 2 mW^2, which is probably not what you want.
dBs are confusing. Different fields have slightly different conventions. People talk about any factor of 2 as a 3 dB change, when technically it should only be relative to power-like quantities. It's weird that some of these "units" can be added together, while others can't. The factors of 10 and 20 can be confusing.
But if you consider the units from a dimensional analysis standpoint, decibels are much more sane and intuitive than they appear.
Earlier quoted context omitted.
The same can be said of any unit. "If you just learn to work with it regardless of its weirdness, it's completely normal" doesn't mean the standard isn't ridiculous. I don't think anyone has stated that a logarithmic scale is bad. The type of logarithmic scale changing depending on the field it's being used in, and the non-standard notation (dBm being used instead of dBmW for instance), is just inconsistent for no re…
> I don't see a practical reason why dB's normal use can't have been covered by normal prefixes Because instead of numbers going like 1, 10, 100, 1k, 10k, 100k, 1M, 10M, 100M, 1G, and so on when using prefixes, we get a much more smoother numbers of 0 dB, 10 dB, 20 dB, 30 dB, 40 dB, 50 dB, 60 dB, 70 dB, 80 dB, 90 dB. You can see the the number for the dB get bigger, while when using prefixes the numbers get bigger tw…
Earlier quoted context omitted.
[flagged]
It's like telling a chemist that moles are a useless complication. They'll swear up and down how important they but have no reasons except that everyone in the field uses them so they must be important. Sometimes conventions live on past the original need they met and experts are blind to that because they're only experts in using the convention, not evaluating conventions. Moles might have made sense when we didn't…
Moles make sense because atoms exist.
Earlier quoted context omitted.
To be frank, your comment just reads to me as a "stockholm syndrome" type reaction to a needlessly complex unit that you're intimately familiar with. You see the same in HN threads where people complain that eg Git or Rust are needlessly complex, there's a swath of people who are so emotionally invested in how well they understand the ins and outs of Git resp Rust that any suggestion that maybe things could be better…
> volume sliders start at 0 dB and then go down to negative $MUCHO, until complete silence at -Infinity. And then this same unit is also used to measure how loud my coffee machine is. They're not the same unit, at all. The audio software is a skeuomorphism from an analogue mixing console that is applying a change to a signal. 0 is unity gain and deviation from this describes an amplitude variation. This is important,…
Exactly, so why label two different things using the exact same letters in a potentially ambiguous context.
Earlier quoted context omitted.
That depends, the dropped unit could be either a year or a month.
It’s understood in context, that’s the point.
It's a bit like hating numbers, and saying "What do you mean by 'three'; what is it - three volts, three amps, three metres? Clearly 'three' is meaningless, and we should stop using it and all the other numbers besides." decibels are simply a dimensionless ratio, used as a multiplier for some known value of some known quantity. In every context where decibels are used, either the unit they qualify is explicitly speci…
> It's a bit like hating numbers, and saying "What do you mean by 'three'; what is it - three volts, three amps, three metres? No, it’s a bit like saying “for chocolate M&Ms, 3 obviously means 9, to compensate for the fact that they’re much smaller than the peanut ones”.
This seems exceedingly ignorant of the work decibels do in telecommunications, RF and fibre engineering. The voltage vs power relationship is something that exists and is a core memory of beginner blunders in the field, but it boils down to a simple 10 vs 20 division operation. Besides that, the decibel simplifies a lot of multiplying very small and very big numbers to summing of two-digit numbers that you can do in…
Yeah that was my thought as well. Decibels make it much easier to do link budgets as you can just add or subtract instead of multiplying or dividing.