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A dumb question


Leon Transaxle
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[quote name='Leon Transaxle' timestamp='1345218583' post='1775177']

I don't know.
Maybe light bulbs weren't the best example as the production of light is a inefficient process involving much heat as a by product so there are too many other variables in the equation.
Its the old candlepower unit that made me think of it.
[/quote]
Hmm, candelas and lumens and stuff? Hmmm, now you've got me unsure. Anyway, thats definitely a situation where perception comes into play, which was why I picked up on it.

As for the spuds, if you got some extra dense ones, then that would definitely be double the weight but not double the volume. (Although maybe that's just double the mass, not double the weight .. I dunno, that's physics, and I'm tired ...)

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[quote name='mart' timestamp='1345217453' post='1775160']But are two light bulbs really twice as bright as one? They are brighter, sure, but are they twice as bright?[/quote]

[s]Watt[/s] what...... if one light bulb (it's not a bulb - it's a lamp!), what if one light bulb was a 30 watt - and the other was 60 watt? Eh? What?
Still not twice as bright! Or .......... is it? ........ and should it be wired in with speaker cable, or instrument cable?

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[quote name='Big_Stu' timestamp='1345326759' post='1776405']


[s]Watt[/s] what...... if one light bulb (it's not a bulb - it's a lamp!), what if one light bulb was a 30 watt - and the other was 60 watt? Eh? What?
Still not twice as bright! Or .......... is it? ........ and should it be wired in with speaker cable, or instrument cable?
[/quote]
30 watt and 60 whats?
In that case you'd need to check the impedances, otherwise you might get magic smoke coming out of your bass.

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I suspect many new bassists have all fallen into the trap of buying bigger and better amps all in the quest for more power, only to realise that it's not necessarily as simple as more watts equalling more power! Call me cynical, but I bet a few manufacturers use this misunderstanding to sell products to those who perhaps don't know better. I know that it's taken me a long time to get my head around stuff like this.

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[quote name='fretmeister' timestamp='1345326573' post='1776404']
A 120w bulb is actually more bright than two 60w bulbs as it is more efficient in the visible spectrum.

But you measure that in lumens and not the watt rating.
[/quote]

As is clearly demonstrated by energy-saving CFL lamps where a 15W CFL is roughly the same brightness as a 60W incandescent.

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[quote name='flyfisher' timestamp='1345370067' post='1776631']
As is clearly demonstrated by energy-saving CFL lamps where a 15W CFL is roughly the same brightness as a 60W incandescent.
[/quote]

It's time for a similar breakthrough in loudspeakers. They, like incandescent bulbs, use around 90% of the amp's output power to produce heat and 10% is converted to sound.

Any ideas?

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[quote name='dincz' timestamp='1345371985' post='1776684']
Any ideas?
[/quote]

How many alternative designs do you want?

http://en.wikipedia.org/wiki/Loudspeaker[list]
[*]
[list]
[*][url="http://en.wikipedia.org/wiki/Loudspeaker#Horn_loudspeakers"][color=#000000]Horn loudspeakers[/color][/url]
[*][url="http://en.wikipedia.org/wiki/Loudspeaker#Piezoelectric_speakers"][color=#000000]Piezoelectric speakers[/color][/url]
[*][url="http://en.wikipedia.org/wiki/Loudspeaker#Magnetostrictive_speakers"][color=#000000]Magnetostrictive speakers[/color][/url]
[*][url="http://en.wikipedia.org/wiki/Loudspeaker#Electrostatic_loudspeakers"][color=#000000]Electrostatic loudspeakers[/color][/url]
[*][url="http://en.wikipedia.org/wiki/Loudspeaker#Ribbon_and_planar_magnetic_loudspeakers"][color=#000000]Ribbon and planar magnetic loudspeakers[/color][/url]
[*][url="http://en.wikipedia.org/wiki/Loudspeaker#Bending_wave_loudspeakers"][color=#000000]Bending wave loudspeakers[/color][/url]
[*][url="http://en.wikipedia.org/wiki/Loudspeaker#Flat_panel_loudspeakers"][color=#000000]Flat panel loudspeakers[/color][/url]
[list]
[*][url="http://en.wikipedia.org/wiki/Loudspeaker#Distributed_mode_loudspeakers"][color=#000000]Distributed mode loudspeakers[/color][/url]
[/list][*][url="http://en.wikipedia.org/wiki/Loudspeaker#Heil_air_motion_transducers"][color=#000000]Heil air motion transducers[/color][/url]
[*][url="http://en.wikipedia.org/wiki/Loudspeaker#Plasma_arc_speakers"][color=#000000]Plasma arc speakers[/color][/url]
[*][url="http://en.wikipedia.org/wiki/Loudspeaker#Digital_speakers"][color=#000000]Digital speakers[/color][/url]
[/list]
[/list]

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Theoretically, if two identical sound waves are perfectly in phase then the amplitude of the wave doubles and hence the volume is doubled, so two 100w amps should feasibly produce double the volume of one.

However if the waves are perfectly out of phase then the waves cancel each other out, total amplitude is always zero, resulting in silence.

In reality, wave physics don't really work as they do on paper!

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[quote name='D.I. Joe' timestamp='1345420467' post='1777408']
Theoretically, if two identical sound waves are perfectly in phase then the amplitude of the wave doubles and hence the volume is doubled, so two 100w amps should feasibly produce double the volume of one.

However if the waves are perfectly out of phase then the waves cancel each other out, total amplitude is always zero, resulting in silence.

In reality, wave physics don't really work as they do on paper!
[/quote]
The power of the waves double, but your ears work logarithmically so you don't perceive that as twice the volume.

I don't think anybody's mentioned that the number of speakers has doubled in the OP's scenario, just to muddy the water and add to the confusion. ;)

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[quote name='Musky' timestamp='1345447309' post='1777465']

The power of the waves double, but your ears work logarithmically so you don't perceive that as twice the volume.

[/quote]

Ah I didn't know that, we didn't cover the human ear in A-Level physics :rolleyes:

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[quote name='derrenleepoole' timestamp='1345366348' post='1776590']
I suspect many new bassists have all fallen into the trap of buying bigger and better amps all in the quest for more power, only to realise that it's not necessarily as simple as more watts equalling more power! [/quote]

You've demonstrated your own point very well there! More Watts, by definition, does equal more [i]power[/i]. ;) The problem is that it is not straightforward to translate between power and [i]volume[/i], and it becomes even more complicated when you realise that some manufacturers quote RMS power whilst others quote Peak Power.

[quote name='D.I. Joe' timestamp='1345420467' post='1777408']
Theoretically, if two identical sound waves are perfectly in phase then the amplitude of the wave doubles and [i]hence the volume is doubled[/i], so two 100w amps should feasibly produce double the volume of one.
[/quote]

No. :yarr: Perceived volume does not work like that I'm afraid! Doubling the power output will increase the volume, but not by a factor 2. The rough rule of thumb is that you need ten times as much power to sound twice as loud to the human ear. So a 100W amp is twice as loud as a 10W amp, and a 1000W amp is twice as loud as a 100W one.

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[quote name='D.I. Joe' timestamp='1345451835' post='1777525']
Ah I didn't know that, we didn't cover the human ear in A-Level physics :rolleyes:
[/quote]

The psychology of perception is as important as the basic physics - actually, probably more so, as it's the brain that really 'hears' sounds and constructs the image of the world we 'see' through our eyes.

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[quote name='uncle psychosis' timestamp='1345455428' post='1777585']
You've demonstrated your own point very well there! More Watts, by definition, does equal more [i]power[/i]. ;) The problem is that it is not straightforward to translate between power and [i]volume[/i], and it becomes even more complicated when you realise that some manufacturers quote RMS power whilst others quote Peak Power.[/quote]

That's exactly the point I mean - power doesn't always equate to volume. That's what I was trying to say *honest* ;)

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