MCMIV was 1904 when I went to school back in the day. Kinda like MMXXIV.
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There are four Cs there making it 1904. But arenāt you supposed to use the fewest letters possible?
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There are several standards or conventions
Depends on whether you favour additive IIII for 4
or subtractive IV for 4
What is missing is a symbol for zero. You cant have a positional notation like our decimal numbers unless you have a place marker for zero.
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I did a search for āis mdcccciv a proper roman numeralā.
It says no. The most of one symbol you should have in a row is three.
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Roman numerals are a bit cumbersome, but kind of OK, as long as you are only counting, say, for storage inventories.
Once you want to do interest calculations or engineering work, they become a mess.
Thatās why Arabic numerals (which are, in reality, not Arabic, but from India) became such a hit.
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HI,
Iām so sorry for this off-topic
Iāll give you my opinion on when we talk about db
When we talk about db, particularly in audio, we have to be careful to know what db weāre talking about: it can be db, dbv, dbu, etcā¦
Decibel (db)
On the other hand, an increase of 3db in audio means doubling the sound pressure, but the human ear doesnāt respond to such linear variations, which is why an increase of 10 db seems to be twice as much to the human ear.
example: db Decibel ratings
Our ear does not respond equally to all frequencies and this is a graph of the average threshold sensitivity of the human ear. Of course, not everyone has the same response (ability) to hear the same frequencies in the same way.
This is the human hearing threshold graph used in psychoacoustics, which is the branch of psychophysics that involves the scientific study of the relationship between auditory sensations and the physical characteristics of sound, such as amplitude, frequency and timbre.
source: wikipedia - Psychoacoustics
When we are listening to a sound with several frequencies, you could call it music, for example, our ear adapts its auditory response according to the amplitude of the sounds, for example: if we hear a very high frequency and immediately afterwards a very low frequency, our ear canāt hear that very low frequency because the response of the human ear is slow, that is, it takes some time to recover from the sound pressure of the higher frequency, and the response curve of the human ear changes constantly.
source: wiki - Psychoacoustics
Many audio format converters use the method of psychoacoustics, i.e. they analyze the audio that is to be converted and all the frequencies that are below a certain frequency with greater intensity over a certain period of time are removed, because the human ear doesnāt hear them, which may not be true, because we donāt all hear the same way.
So, using your reference in DB, an increase of 10 DB may even be detrimental to what you are listening to, because you are increasing the sound pressure and the human ear will take longer to recover from the pressure of a very high frequency and, even if the lower frequencies are recorded, you will have more difficulty hearing them, so if codecs are used. This is one of the āwarsā between analog, digital and compressed audio (codecs).
Please note: this is my humble opinion. In no way am I trying to contradict anything that has been said here, on the contrary, Iām trying to complement what has been said.
I even accept that Iām completely wrong on this subject. I just wanted to comment on the fact that we talk about DB for audio.
Jorge
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Hi Paul,
Thanks for this thread.
About 40 years ago, I bought a slide rule, although calculators were already used at school, I wanted to know how it works.
Needless to say, at the time, there was no internet and I had great difficulty learning the logic of how the slide rule works and I never met anyone who knew how to use it.
Honestly, I donāt even know if I still have it, but because of your topic, Iām very curious and Iām going to look for it.
If I find it, I will respond to the topic again.
Thank you very much in advance for bringing this topic to the forum
Jorge
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Hi Jorge
Thanks for your detailed reply on sound.
Just to add a little to that and other things to consider
Age, as we get older some frequencies are lost to us, more so if you worked in environments of loud sounds such as musicians, factories and even some offices.
Sex, yes the males do loose more than female, I find myself in a meeting if several are speaking then I may loose the story and not be able to difference the contents
And finally marriage, we are trained to say yes dear no matter what ā¦
sorry could not resist a bit of humor.
And NOT true in my case as still trying to learn the language dĆ©solĆ© je ne comprends pasā¦ works the same.
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Psychoacustics (perceived loudness) is indeed an entirely different story, and a fascinating one!
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Hi Mina,
Youāre absolutely right: itās very fascinating.
A long time ago, I had to study this topic a lot and I really enjoyed it.
Iām glad to see you again on the forum
Jorge
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Hi Paul,
Completely true: my left ear has a different frequency response to the right ear due to a professional defect and the hearing curve changes a lot depending on age, I notice it especially in the high frequencies. You know that age when we start to notice that difference in hearing? For me it was Ā± when I was 40 years old or older? I was very stressed about this because I worked in audio. Now I donāt care much anymore (itās a lie, I get frustrated! I still work with audioā¦)
āSex, yes the males do loose more than femaleā
Sorry ladies, no offense no offense about what Iām going to write nextā¦
Do men lose more than ladies, or do ladies hear āmoreā than men?
- āDid you hear what that guy/lady said across the street?ā
- āWhat? What do you say?ā
- āyou never hear anything!!!ā
Solution:
- āYes, yes, I heardā
The problem is when they ask the following question: - āand what is your opinion?ā
- āI donāt comment on this subjectāā
It usually resultsā¦ Itās almost āyes dearā
This is a bit of humor too
All users already know me and know that Iām not like that
Jorge
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Psychoacustics new word for me, had to look it up to understand, a whole different ball game.
One thing on this site is the vast experiance and knowledge of members. It appears every day i learn something new and not always about linux or technology.
Thanks for sharing that mina
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To follow the story of jorge with a bit more humor
Man went to the doctor and said you must see my wife, she is deaf
Doctor says do this test and come back to tell me the results
Stand 20 m away and ask her a question and see if she replies
Then stand 10 m away and ask the same question see if she replies
Then stand 5 m away and as, again
Thrn stand next to her and ask again.
Man returns to doctors the following week to giventhe resultsā¦
20 m nothing, 10 m nothing, 5 m nothing, stood next to her and asked again, she replied I have a.ready told you 5 times ā¦
Ha ha ha
So what did you do in audio, or still do ?
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You have to admire Ptolemy. The Greeks used letters for numbers, like the Romans , for everyday use, but the Greek Astronomers used a base 60 number system derived from the Sumeriansā¦ it had integers, and fractions ( ratios of integers) and that is all ā¦ no zero and no irrational numbers.
Can you imagine calculating the positions of the planets with that? I would have trouble doing all those epicycles and deferents with our arabic numbers, but to do it with integers and fractions, to base 60, is amazing. I believe they used lots of lookup tables.
It was not so long ago that computers only had integer hardware. I dont know of any computer that dealt with fractions.?
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When I noticed it was different than when it happened, Iām sure. I was listening to a podcast and the host apologized for a noise in the previous episode. He said someone asked him what the high frequency whine was, but the host could not hear it. He went back to the recording and found there was one there if he turned it up loud enough. It turns out he had a new piece of equipment (a USB mic maybe) and that was causing the whine.
After that I found some site online and generated sounds at different frequencies and was shocked at how low the āhigh frequenciesā I could hear were for me.
Slightly different experience too. I have some nice Sony noise cancelling headphones I sometimes wear in the office. Just play some Yacht Rock at a low volume and work away. It always shocks me how loud it is in the office when I take them off. Just the HVAC is super noisy. They also play some white noise over a speaker system to make the environment seem quieter.
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Hi Paul,
Me?
Iām an electronics technician and I worked for many years in after-sales service repairing analog and digital audio and other systems. Have you ever heard or heard of the Sony MiniDisc MZ-1 (1992)?
Source: https://www.minidisc.wiki/equipment/sony/portable/mz-1
It was the first time I heard about psychoacoustics during all the various training sessions on this equipment.
Now Iām still working with audio and other systems, but as a maintenance technician on other company, so that we havevto keep the company running 24/7, 365 days a year.
Jorge
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I could never afford the sony equipment at that time and now just happy with alexia entry level model good enough for the radio i listen too.
Always appears strange to have white noise as a sound cancelling system. Stayed in a hotel over last Christmas and they had it in the room but did not find it different
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Reminds me of a story I was told. Donāt know if was true.
In college classes, the students would set there cell phone ring (or maybe text notice) to a frequency that the professor could not hear because of their age.
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I need that for my phone, fed up of sms, WhatsApp and mail in the middle of the night and its not just mine its my wife as guilty
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I had to really laugh at this. My wife seem to be always talking. Not necessary to me all the time, just thinking (talking) out loud to her self. So being together for so long and her constant talking, I have kind of tuned her out which is not always good.
When I say, āI didnāt know about that.ā Quite often I get, āBut I told you that already!ā 
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