Clear in context. People write things like dB SPL (A-weighted) in spec sheets because spec sheets benefit from being unambiguous. Most of the time it’s really clear, like you’re talking about insertion loss or amplifier gain and there’s only one reasonable way to interpret it.
But for insertion loss and amplifier gain it is "just" dB, it's the ratio of the input to the output. The amplifier has a gain of 35 dB means its output is 35 dB higher than the input. If the input is -30 dBm the output is +5 dBm, etc. The reference for an amplifier, or insertion loss is clear in context since you're talking about the gain / loss of a device, and isn't referenced to any fixed scale like db relative to 1 mW, SPL (A-weighted), or 1 volt.
On detailed spec sheets they list the gain of amplifiers as xxx dB.
no it's not - it's assumed by maybe taking the most likely unit (year). But if the conversation is in hospital with your kid having emergency I guess doctor would appreciate to know if they will have to do surgery on 3 months child or 3 years kid.
If the doctor has trouble figuring out the difference between 3 months and years, there are bigger problems than specificity.
There are places specificity is necessary, and there are places the implicit assumptions people make are specific, and only need additional specification if the implication is violated. That's how language works - shortcuts everywhere, even with really important things, because people figure it out. There are also lots of examples of this biting people in the ass - it doesn't always work, even if most of the time, it does.
As long as you construct a strawmen strict enough that can be no ambiguity, and refuses to acknowledge any context where it's not enough, yeah, it always make sense in context.
No one actually says "my child is 3" meaning anything other than 3 years. They would say "3 days", "3 weeks" or "3 months" meaning the other lengths of time.
Not where I live. You'd never specify how old somebody is with a bare number and have it mean anything other than years in the US. "My kid is 3" is always 3 years. So is "How old is your Tammy?" "Three". That only ever means years. Every other unit is always explicit. In my decades as a parent and being around other parents of kids and newborns, I've never experienced an exception to this.
That's the point. If you are talking colloquially to someone where you live, sure, whatever, this doesn't matter. But if you are writing something down in some publication for a wide and unpredictable audience, you should use units.
Most of the time if someone says "he's 3", it is a good bet that they mean 3 years. People usually specify if they mean days/weeks/months with respect to someone's age. Not always, of course, but it's definitely uncommon to drop the unit when it's anything except years.
That only works if you're already familiar with the context and system and assume other people are too and don't care about anyone new to that area. (Good luck coming to the audio equipment datasheet with no experience and figuring out what the dB means in each case) "He's 3" works because of the previous question and because everyone had experience of talking about age.
dB for anyone not already knowing the answer is like going to another planet and hearing "he's 3". Of course it's on a logarithmic scale, offset to -5 as starting point, counting the skin shedding events - clear in context and you should've known that.
Maybe I just live on the planet, but I don’t have this problem with dB and to me, it sounds like you’re the alien. Maybe you could elaborate, or give a motivating example?
I just don’t remember encountering the problem you’re describing, and it’s unfamiliar to me. There’s something about your experience that I don’t understand, but I don’t know what it is.
Moving from EE to audio to radio is enough to go through a few iterations of "people just write dB but mean completely different things". I got used to it, but that doesn't stop me from saying it's a bad idea and we should improve things for the next person.
I often see pop sci articles saying something like '400 dB would represent a sound strong enough to tear the world apart', or 'military sonar is X dB -- strong enough to liquefy your organs at Y distance'. It's rarely clear to me which of these usages of 'dB' are directly comparable. I think the dB measurement for sonar is a different scale/unit than the one for hearing damage thresholds in air, but I couldn't figure out how to convert between the two last time I spent a few minutes trying to look it up, so in my opinion it can be fairly confusing.
Yes. The point is that for some reason dB seems particularly susceptible to people dropping the units.
For instance, I've heard loudness of sounds described in decibels for my whole life, and first saw the actual units people are describing when I read this article and thread today.
That’s because you’re a casual observer. If you’re an audio engineer, recording things, designing microphones, amps, or speakers, then you’d know it. Trust me. I’m a digital electrical engineer (computer engineering, basically). I thought that dBs were weird, too. My dad worked in microwave communications systems for his career and dBs are perfectly natural for him. Ditto my daughter who is an audio engineer. Dropping units when you’re working in a particular field is quite common, as who wants to be needlessly wordy when it’s redundant and everyone in the industry understands it? IMO, this article is just the author raging about his own ignorance.
That's the whole point. You're failing to communicate clearly. You think it's fine because you're used to it. But it's bad. That you are used to and comfortable with something does not imply that it is not bad.
There are two paths: "it was weird but then I got used to it, you're just ignorant" or "it was weird, I got used to it, but we should improve the situation". I know which side I want to be on. Even if it takes decades like the data SI prefixes.
No, it doesn't make perfect sense. It's a bad practice to leave off units. You just got used to it and seem to have developed pride in being in the in-crowd of people comfortable with an unclear jargon, and that has now blinded you to a bad status quo. Many such cases!
> You’re discounting familiarity as being stupid. The real path is “it was weird but once I spent some time with it, it made perfect sense.”
I don't think either of your parent's paths say that:
> There are two paths: "it was weird but then I got used to it, you're just ignorant" or "it was weird, I got used to it, but we should improve the situation". I know which side I want to be on. Even if it takes decades like the data SI prefixes.
I believe that they're saying that, yes, experts get used to it, after which it makes complete sense (as would any arbitrary but consistent convention, once you got used to it), but, in any living field, there will constantly be non-experts looking to become experts. If there is a way to make the process easier for them while not introducing any lack of precision that would hamper experts, then why not?
But dB without reference makes sense in many many occasions. Either because the reference is implicit (not ideal, but we have many implicit assumptions in communication), or because it's genuinely a ratio. Attenuation, gain.
If you every find an "official" written document that uses dB not as attenuation/gain and is not specifying the reference (at least in a footnote), it's written either by idiots or for idiots, or both.
dB(A) is a weighting. It’s not a reference and it’s not units. I think some of the confusion here comes from people not actually understanding units.
A-weighting describes how different frequencies are summed up. It’s like saying “RMS”. RMS is not units, A-weighting is not units. You can apply A weighting to voltage, digital signals, or audio. They all have different units but can all be A-weighted.
You could invent a new unit for A-weighted audio, but you would need several.
If you were writing a research paper or engineering artifact rather than having a casual conversation, you should specify the units ("years old") for age as well.
“How old is your son?” “He’s 3.”
Clear in context. People write things like dB SPL (A-weighted) in spec sheets because spec sheets benefit from being unambiguous. Most of the time it’s really clear, like you’re talking about insertion loss or amplifier gain and there’s only one reasonable way to interpret it.