How much is twice as loud?

[busb]

I was very surprised to read just how much it was! I invite you to guess before googling if you don't already know the (correct?) answer.

It's surely a very subjective measure anyway & a bit like trying to quantify something like "twice as hot". I'd love to know how the equivalent power in either watts or dBs was arrived at!

 

[abacus]

The ear processes sound in a logarithmic form not a linear form, therefore volume doubling requires 10 times the power (10db), compared to 2 times the power if it was in a linear form.

Example:

1w = 50db

10w = 60db

100w = 70db

1000w = 80db

Each 10db is a doubling of volume.

Bill

 

[altruistic.lemon]

I thought it was 3db.

 

[tyranniux42]

3db is the half power point if memory serves and is often used as a benchmark figure such as for frequency response

 

[tyranniux42]

The ear processes sound in a logarithmic form not a linear form, therefore volume doubling requires 10 times the power (10db), compared to 2 times the power if it was in a linear form.

Example:

1w = 50db

10w = 60db

100w = 70db

1000w = 80db

Each 10db is a doubling of volume.

Bill

10db isn't 10 times power, to double your power it's 6db I think. My degree seems such a long time ago...

 

[tyranniux42]

The ear processes sound in a logarithmic form not a linear form, therefore volume doubling requires 10 times the power (10db), compared to 2 times the power if it was in a linear form.

Example:

1w = 50db

10w = 60db

100w = 70db

1000w = 80db

Each 10db is a doubling of volume.

Bill

10db isn't 10 times power, to double your power it's 6db I think. My degree seems such a long time ago...

ive both contradicted my first post which was correct and also incorrectly said you were wrong. 10db is 10 times power.

3db as I stated before is half power and therefore also double power point.

 

[tyranniux42]

The ear processes sound in a logarithmic form not a linear form, therefore volume doubling requires 10 times the power (10db), compared to 2 times the power if it was in a linear form.

Example:

1w = 50db

10w = 60db

100w = 70db

1000w = 80db

Each 10db is a doubling of volume.

Bill

10db isn't 10 times power, to double your power it's 6db I think. My degree seems such a long time ago...

ive both contradicted my first post which was correct and also incorrectly said you were wrong. 10db is 10 times power.

3db as I stated before is half power and therefore also double power point.

 

[sogophonio11]

My degree(S) Were a while ago also. I remember the answer to this question! Units relating to loudness= the "Phon" As in SogoPHONio!

Silly reply to a silly question with all due respects! Question- What does the rest of my username stand for? Answers on a postcard please.:?

Cheers.

 

[sogophonio11]

Silly reply also! Apologies! Business just collapsed( Suicidal) And Pissed!!!

Damn this recession. |(

 

[CnoEvil]

Silly reply also! Apologies! Business just collapsed( Suicidal) And Pissed!!!

Damn this recession. |(

Very sorry to hear this.

Coming on here and ranting helps (a little).

 

[sogophonio11]

Should be in london now, doing what i know best! OUTSOURCING, what the Fxxx does that mean then? Acolades last week, Pxxx off now!

Ah what the hell, who cares any way. Hundred grand a year to nowt in one easy step. :O :doh: :wall: :shhh: :shame: :type:

 

[sogophonio11]

Thanks Cno. No ranting on here is not the right thing to do really, sorry all Known about this for a few days now. Still have some silly little contracts with provincial theatre ops. But what really gets me is i was the best sound board man in theatre land! Now it seems, the local soho electronics people can do a cheaper/ better job! Sorry being a little silly now.

Off out with my brother now, finish the :cheers: job off properly! Am sure this bad patch will pass eventualy?:boohoo:

 

[CnoEvil]

Thanks Cno. No ranting on here is not the right thing to do really, sorry all Known about this for a few days now. Still have some silly little contracts with provincial theatre ops. But what really gets me is i was the best sound board man in theatre land! Now it seems, the local soho electronics people can do a cheaper/ better job! Sorry being a little silly now.

Off out with my brother now, finish the :cheers: job off properly! Am sure this bad patch will pass eventualy?:boohoo:

Talent usually comes through.......so hang in and things will turn.

 

[sogophonio11]

What a nice guy you are Cno Must go now, night life calling :wave:

 

[davedotco]

Oh dear....... :O

The ear does process SPL in a logarithmic fashion and works roughly like this.

The smallest change in SPL that can be heard by a 'normal' person is 1dB. Many need a 2dB change to be positive and this is with a test signal.

A clearly percieved increase in level on a music signal is probably closer to 3dB, depending on how the test is done.

A 6dB increase in SPL requires a doubling of amplifier power, a 10dB increase requires 10 times the power, OK so far?

This has implications. For example, a pair of averagely sensitive speakers, say 89dB (1watt, 1meter) produce roughly that level at a normal listening distance in a normal room, this is loud, a more normal 'serious' listening level is around 79dB, requiring 0.1watt, not very much you might think.

So let us play a quality modern recording with a dynamic range of 60dB, remember a CD has a theoretical 96db range. Assuming the average level is 79dB then the average power required from the system is just 0.1watt. Peak level however is 30dB (half of 60dB) higher, ie 10 x 10 x 10 times higher, 100watts in this case.

So you have some new music, or a new bit of kit and invite a few friends round to show off and you turn it up a bit, another 6dB and we are talking 200watts and that is before you build in anf headroom, a professional system will usually have 3 - 6dB, sometimes more.

Choose a less sensitive model, a PMC or a small ATC and a 200watt amplifier is barely adequate and if you are having a party, just forget it.....

Quick and dirty admitedly, but it does give you an idea of what power is required to make a hi-fi system work.

 

[Overdose]

Oh dear....... :O

The ear does process SPL in a logarithmic fashion and works roughly like this.

The smallest change in SPL that can be heard by a 'normal' person is 1dB. Many need a 2dB change to be positive and this is with a test signal.

A clearly percieved increase in level on a music signal is probably closer to 3dB, depending on how the test is done.

A 6dB increase in SPL requires a doubling of amplifier power, a 10dB increase requires 10 times the power, OK so far?

This has implications. For example, a pair of averagely sensitive speakers, say 89dB (1watt, 1meter) produce roughly that level at a normal listening distance in a normal room, this is loud, a more normal 'serious' listening level is around 79dB, requiring 0.1watt, not very much you might think.

So let us play a quality modern recording with a dynamic range of 60dB, remember a CD has a theoretical 96db range. Assuming the average level is 79dB then the average power required from the system is just 0.1watt. Peak level however is 30dB (half of 60dB) higher, ie 10 x 10 x 10 times higher, 100watts in this case.

So you have some new music, or a new bit of kit and invite a few friends round to show off and you turn it up a bit, another 6dB and we are talking 200watts and that is before you build in anf headroom, a professional system will usually have 3 - 6dB, sometimes more.

Choose a less sensitive model, a PMC or a small ATC and a 200watt amplifier is barely adequate and if you are having a party, just forget it.....

Quick and dirty admitedly, but it does give you an idea of what power is required to make a hi-fi system work.

Playing devils advocate, if all of the above is true, why is it that so many people are happy with much less than 100W amplifiers, 50W even? also, there are many even less powerful valve amplifiers.

Are the owners of such low powered amplifiers always listening at much reduced volume levels, or are the amplifiers in a state of or near perpetual clipping?

 

[davedotco]

Oh dear....... :O

The ear does process SPL in a logarithmic fashion and works roughly like this.

The smallest change in SPL that can be heard by a 'normal' person is 1dB. Many need a 2dB change to be positive and this is with a test signal.

A clearly percieved increase in level on a music signal is probably closer to 3dB, depending on how the test is done.

A 6dB increase in SPL requires a doubling of amplifier power, a 10dB increase requires 10 times the power, OK so far?

This has implications. For example, a pair of averagely sensitive speakers, say 89dB (1watt, 1meter) produce roughly that level at a normal listening distance in a normal room, this is loud, a more normal 'serious' listening level is around 79dB, requiring 0.1watt, not very much you might think.

So let us play a quality modern recording with a dynamic range of 60dB, remember a CD has a theoretical 96db range. Assuming the average level is 79dB then the average power required from the system is just 0.1watt. Peak level however is 30dB (half of 60dB) higher, ie 10 x 10 x 10 times higher, 100watts in this case.

So you have some new music, or a new bit of kit and invite a few friends round to show off and you turn it up a bit, another 6dB and we are talking 200watts and that is before you build in anf headroom, a professional system will usually have 3 - 6dB, sometimes more.

Choose a less sensitive model, a PMC or a small ATC and a 200watt amplifier is barely adequate and if you are having a party, just forget it.....

Quick and dirty admitedly, but it does give you an idea of what power is required to make a hi-fi system work.

Playing devils advocate, if all of the above is true, why is it that so many people are happy with much less than 100W amplifiers, 50W even? also, there are many even less powerful valve amplifiers.

Are the owners of such low powered amplifiers always listening at much reduced volume levels, or are the amplifiers in a state of or near perpetual clipping?

Both.

Measured levels in the home hi fi environment are often much lower than you might think, until you turn it up!

A lot of low powered amplifiers are running close to the edge and how they behave in those conditions may explain the audible differences between them. This applies to both valve and solid state components.

The maxin that 'all competant amplifiers operating within their design parameters sound the same' is probably true, the clue is in the words in italics.

 

[lindsayt]

Overdose, in my case the answer to your question is speakers that are about 103 dbs/2.83v/1m efficient. Amplifier power for home listening becomes academic with speakers like this. The speakers are also only about 1 db down at 20hz. Any music or film sound tracks with bass content have real physical impact when peaking over 90dbs, let alone 100dbs or 110dbs!

 

[lindsayt]

Davedotco a 6db increase in Sound Pressure Level (SPL) requires 4 times the power, not twice. A 9 db increase require 8 times the power and as you quite rightly said 10dbs requires 10 times the power.

If you or anyone is listening so that the average level is 79dbs and peaks are 30 dbs above that, ie 109dbs, then you are listening very loud. So loud that you're at risk of permanently damaging your hearing. You're likely to have ringing ears after listening at these levels.

When I listen at levels where the peaks are at 80dbs and therefore the average levels with a good dynamic recording are at 50 dbs, this still sounds like a generous volume.

And something else to bear in mind is how many dbs drop-off you get between 1m from your speakers and your listening position. I get about 10dbs drop-off in my room.

 

[gasolin]

If you have 2x100 watt, 3db more is 2x200watt

If one speaker is playing 110 db, adding another one that also plays 110 db will increase the total spl to 116db

 

[gasolin]

Oh dear....... :O

The ear does process SPL in a logarithmic fashion and works roughly like this.

The smallest change in SPL that can be heard by a 'normal' person is 1dB. Many need a 2dB change to be positive and this is with a test signal.

A clearly percieved increase in level on a music signal is probably closer to 3dB, depending on how the test is done.

A 6dB increase in SPL requires a doubling of amplifier power, a 10dB increase requires 10 times the power, OK so far?

This has implications. For example, a pair of averagely sensitive speakers, say 89dB (1watt, 1meter) produce roughly that level at a normal listening distance in a normal room, this is loud, a more normal 'serious' listening level is around 79dB, requiring 0.1watt, not very much you might think.

So let us play a quality modern recording with a dynamic range of 60dB, remember a CD has a theoretical 96db range. Assuming the average level is 79dB then the average power required from the system is just 0.1watt. Peak level however is 30dB (half of 60dB) higher, ie 10 x 10 x 10 times higher, 100watts in this case.

So you have some new music, or a new bit of kit and invite a few friends round to show off and you turn it up a bit, another 6dB and we are talking 200watts and that is before you build in anf headroom, a professional system will usually have 3 - 6dB, sometimes more.

Choose a less sensitive model, a PMC or a small ATC and a 200watt amplifier is barely adequate and if you are having a party, just forget it.....

Quick and dirty admitedly, but it does give you an idea of what power is required to make a hi-fi system work.

3 db more power is 2x200 instead of 2x100

6 db dosn't mean that if you have 2x100 and increase the output from the amplifer with 6 db that it's 2x200.. an increas of 6 db is in watt 2x400

 

[lindsayt]

And Overdose, if you're using a typical solid state amp and it's in a state of being perpetually close to clipping, then that's a good thing, because these amplifiers have their lowest levels of THD+N distortion as a percentage when they are close to clipping.

Of course total system THD+N distortion is then likely to depend on the speakers and frequency content of the recording. If you have a modest 20 watt solid state amp playing at levels where 10 watts are being drawn from it then it's highly likely that the speakers will be producing far more THD distortion than the amplifier, especially in the bass region.

 

[busb]

I'm familiar enough working with log ratios in dBs or when referenced to an absolute quantity such with the dBm but equating perceived loudness is far from intuitive to me. I can understand how human's frequency response is measured by switching between a fixed tone as the reference then a stepped tone of perceived equal loudness with the results averaged over several people then repeated according to age but what is twice as loud really mean?

Half power has been mentioned as used with frequency response measurements but that refers to power or amplitude, not loudness. The level difference of 10dB seems to be the agreed amount - not 3dB I'd thought it was.

 

[altruistic.lemon]

3db, 6db and 10db are all correct, it depends what you are measuring. There is an interesting explanatio here: http://www.sengpielaudio.com/TableOfSoundPressureLevels.htm

Didn't get most of it, but the table down the bottom explains things.

 

[Overdose]

Half power has been mentioned as used with frequency response measurements but that refers to power or amplitude, not loudness. The level difference of 10dB seems to be the agreed amount - not 3dB I'd thought it was.

There doesn't seem to be a lot of agreement so far. Several different 'definitive' answers.