Things you always wanted to know the answer to [Vol. 5]
Discussion
number2 said:
Gary C said:
RMS = Root mean square
or the root of the mean of the sum of the squares
essentially, its an equivalent measurement to DC so a 5V RMS signal has the same power to a load as a 5V DC signal
PMPO, peak music power output just allowed advertisers to use a bigger and meaningless number
Wasn't PMPO about 4 x RMS or was there a similar rule of thumb? Was there also PMO figure as well, which was about 2 x? or the root of the mean of the sum of the squares
essentially, its an equivalent measurement to DC so a 5V RMS signal has the same power to a load as a 5V DC signal
PMPO, peak music power output just allowed advertisers to use a bigger and meaningless number
Edited by Gary C on Tuesday 4th April 14:12
It's all a very long time ago, 30 years +, and I recall pouring over catalogues comparing output figures but the details are hazy
.OK, right, so,
Something that I have always wanted to know since my wife asked me 10 minutes ago, is what is the difference between citizenship and nationality?
I promise I am a mostly functional human being who was brought up with a reasonable grasp of the English language, and yet despite reading various explanations of it, I find myself none the wiser.
This sort of thing:
"In general, to be a national is to be a member of a state. Nationality is acquired by birth or adoption, marriage, or descent (the specifics vary from country to country). Having a nationality is crucial for receiving full recognition under international law. Indeed, Article 15 of the Universal Declaration of Human Rights declares that “Everyone has the right to a nationality” and “No one shall be arbitrarily deprived of his nationality nor denied the right to change his nationality” but is silent on citizenship. Citizenship is a narrower concept: it is a specific legal relationship between a state and a person. It gives that person certain rights and responsibilities. It does not have to accompany nationality."
and
"Citizenship can be seen as a political status because it indicates which country recognizes you as a citizen. Nationality has more to do with the relationship between you and your place of birth and can often be seen as ethnic or racially related. Citizenship can fluctuate since you can be a citizen of multiple places simultaneously and can also renounce your citizenship to a country. On the other hand, you cannot change nationality because it’s innate."
are not particularly enlightening, but all the sources I have found are similar examples of word soup.
I was born in Canada then moved to the UK when I was 4. Am I a Canadian National? Am I a dual national? if so have I been since birth or just since I moved to the UK? do I have Canadian citizenship?
I have only a British passport, and my parents are both British born but moved to Canada before I was born.
Why does it have to be so complex?
why is my brain so small?
Something that I have always wanted to know since my wife asked me 10 minutes ago, is what is the difference between citizenship and nationality?
I promise I am a mostly functional human being who was brought up with a reasonable grasp of the English language, and yet despite reading various explanations of it, I find myself none the wiser.
This sort of thing:
"In general, to be a national is to be a member of a state. Nationality is acquired by birth or adoption, marriage, or descent (the specifics vary from country to country). Having a nationality is crucial for receiving full recognition under international law. Indeed, Article 15 of the Universal Declaration of Human Rights declares that “Everyone has the right to a nationality” and “No one shall be arbitrarily deprived of his nationality nor denied the right to change his nationality” but is silent on citizenship. Citizenship is a narrower concept: it is a specific legal relationship between a state and a person. It gives that person certain rights and responsibilities. It does not have to accompany nationality."
and
"Citizenship can be seen as a political status because it indicates which country recognizes you as a citizen. Nationality has more to do with the relationship between you and your place of birth and can often be seen as ethnic or racially related. Citizenship can fluctuate since you can be a citizen of multiple places simultaneously and can also renounce your citizenship to a country. On the other hand, you cannot change nationality because it’s innate."
are not particularly enlightening, but all the sources I have found are similar examples of word soup.
I was born in Canada then moved to the UK when I was 4. Am I a Canadian National? Am I a dual national? if so have I been since birth or just since I moved to the UK? do I have Canadian citizenship?
I have only a British passport, and my parents are both British born but moved to Canada before I was born.
Why does it have to be so complex?
why is my brain so small?
Gary C said:
RMS = Root mean square
or the root of the mean of the sum of the squares
essentially, its an equivalent measurement to DC so a 5V RMS signal has the same power to a load as a 5V DC signal
I'm going to take this opportunity to check my knowledge about the point of RMS (because it applies to lots of things other than HiFi power outputs)or the root of the mean of the sum of the squares
essentially, its an equivalent measurement to DC so a 5V RMS signal has the same power to a load as a 5V DC signal
RMS is simply a way to get a meaningful average from a thing that spends as much time with a negative value as it does a positive one (like a sine wave, but other things too), because if you take a normal average of a wave like that then you get zero, and that is not very useful. So squaring it turns all the negative values into positive ones (because a negative multiplied by any other negative gives a positive number because that's the rules of maths), but then you end up with an average that is the square of the value you really want, so you then take the square root to bring it back down to what it should be.
Correct?
SteveStrange said:
number2 said:
Gary C said:
RMS = Root mean square
or the root of the mean of the sum of the squares
essentially, its an equivalent measurement to DC so a 5V RMS signal has the same power to a load as a 5V DC signal
PMPO, peak music power output just allowed advertisers to use a bigger and meaningless number
Wasn't PMPO about 4 x RMS or was there a similar rule of thumb? Was there also PMO figure as well, which was about 2 x? or the root of the mean of the sum of the squares
essentially, its an equivalent measurement to DC so a 5V RMS signal has the same power to a load as a 5V DC signal
PMPO, peak music power output just allowed advertisers to use a bigger and meaningless number
Edited by Gary C on Tuesday 4th April 14:12
It's all a very long time ago, 30 years +, and I recall pouring over catalogues comparing output figures but the details are hazy
.
Fermit said:
To muddy the waters further, I understood there were at one point 4 measurements. PMPO, MPO, RMS and DIN. I can't remember where DIN sat in the scale of things, but am 90% sure it did exist. Likewise I recall RMS is around 4 x greater output than PMPO, EG 1 watt RMS is 4 watt PMPO. AFAIK pretty much everything nowadays is RMS. Shame, it would make some great bragging rights, my 7 channel 700 watt amp would be 2800 watt PMPO
I think PMPO was 1.41 x RMS (1.41 being an approximation of square root of 2)In the case of your 700 Watt 7 channel amp I imagine that the actual figure is 100W per channel giving the total of 700 (which is another reason car amplifiers can have higher figures than domestic radios as they tend to have more channels)
deadtom said:
I'm going to take this opportunity to check my knowledge about the point of RMS (because it applies to lots of things other than HiFi power outputs)
RMS is simply a way to get a meaningful average from a thing that spends as much time with a negative value as it does a positive one (like a sine wave, but other things too), because if you take a normal average of a wave like that then you get zero, and that is not very useful. So squaring it turns all the negative values into positive ones (because a negative multiplied by any other negative gives a positive number because that's the rules of maths), but then you end up with an average that is the square of the value you really want, so you then take the square root to bring it back down to what it should be.
Correct?
YepRMS is simply a way to get a meaningful average from a thing that spends as much time with a negative value as it does a positive one (like a sine wave, but other things too), because if you take a normal average of a wave like that then you get zero, and that is not very useful. So squaring it turns all the negative values into positive ones (because a negative multiplied by any other negative gives a positive number because that's the rules of maths), but then you end up with an average that is the square of the value you really want, so you then take the square root to bring it back down to what it should be.
Correct?
In simple terms if you put 5V DC and then 5V RMS into a resistor, they will both dissipate the same amount of heat from that resistor. If you use RMS you can compare any source no matter its waveform.
Edited by Gary C on Thursday 6th April 10:53
Clockwork Cupcake said:
98elise said:
Error 404 is correct. RMS is the proper scientific term. PMPO is just made up marketing b
ks.
I remember seeing a small Sony system rated at something like 300W PMPO with a mains power consumption of something like 18W. Seems Sony invented a machine that outputs more power/energy than it consumes!
Watts of electrical consumption is not the same as Watts of music output.ks.I remember seeing a small Sony system rated at something like 300W PMPO with a mains power consumption of something like 18W. Seems Sony invented a machine that outputs more power/energy than it consumes!
PMPO is marketing b
ks IMO. It became a thing some time after my electical/electronics training though.Gary C said:
if you have a 10V sine wave peak, then thats
7.1V RMS
20V peak to peak
into a 8 ohm speaker P = V²/R
= 6 W RMS
or
= 50W Peak music power
You can see why marketing people wanted to use Music Power
Peak to peak is nonsense though in the power equation?7.1V RMS
20V peak to peak
into a 8 ohm speaker P = V²/R
= 6 W RMS
or
= 50W Peak music power
You can see why marketing people wanted to use Music Power
Edited for spelling!
Edited by 98elise on Thursday 6th April 14:11
98elise said:
Gary C said:
if you have a 10V sine wave peak, then thats
7.1V RMS
20V peak to peak
into a 8 ohm speaker P = V²/R
= 6 W RMS
or
= 50W Peak music power
You can see why marketing people wanted to use Music Power
Peak to peak is nosense though in the power equation?7.1V RMS
20V peak to peak
into a 8 ohm speaker P = V²/R
= 6 W RMS
or
= 50W Peak music power
You can see why marketing people wanted to use Music Power
Thats only really in numbers, heat is still produced no matter what way the electricity is flowing.
Frimley111R said:
When people get divorced, how does one person sometimes end up with nothing/everything? Surely its a basic split down the middle?
It's seldom as clear-cut as that. Especially when children are involved. And/or there is asymmetric financial worth / earning potential. In an ideal world, all things being equal, then yes it should be an equal split. But it is not an ideal world and things are rarely equal.
Gary C said:
98elise said:
Gary C said:
if you have a 10V sine wave peak, then thats
7.1V RMS
20V peak to peak
into a 8 ohm speaker P = V²/R
= 6 W RMS
or
= 50W Peak music power
You can see why marketing people wanted to use Music Power
Peak to peak is nosense though in the power equation?7.1V RMS
20V peak to peak
into a 8 ohm speaker P = V²/R
= 6 W RMS
or
= 50W Peak music power
You can see why marketing people wanted to use Music Power
Thats only really in numbers, heat is still produced no matter what way the electricity is flowing.
Power is the rate of energy consumption. If you throw peak to peak into the equation where is the extra heat coming from, and where is it going?
As I said Its been quite some time I did this as theory but I can't see how the physics has changed because of a marketing gimic
Edited to explain a little more clearly!
Using your example of a 10v sine wave into 8 ohms. Take any point on the peak to peak wave and throw the figures in to P = V²/R
V peak is + or -10 volts. Both will give you (+)12.5 watts peak. At no point is the answer 50 watts.
Edited by 98elise on Thursday 6th April 14:52
Clockwork Cupcake said:
Frimley111R said:
When people get divorced, how does one person sometimes end up with nothing/everything? Surely its a basic split down the middle?
It's seldom as clear-cut as that. Especially when children are involved. And/or there is asymmetric financial worth / earning potential. In an ideal world, all things being equal, then yes it should be an equal split. But it is not an ideal world and things are rarely equal.
My father left, and he was the big earner. By the time they divorced he had multiple houses and a much bigger income than when he left.
He kept his new houses and half my mother's house. In recent years he has been trying to get his half of the money out of her house.
Sometimes women get screwed over by the system as well.
Gassing Station | The Lounge | Top of Page | What's New | My Stuff