watts and volume

bluesfloyd

bluesfloyd

New member
hi guys,
in general if i had a 15 watt/ 30 watt/ 60 watt amp, is a 30 watt twice the volume of a 15 watt, and a 60 watt twice the volume of a 30 watt ????
thanks guys for taking time to anwser this post,

all the best, bluesfloyd
 
Re: watts and volume

bluesfloyd said:
hi guys,
in general if i had a 15 watt/ 30 watt/ 60 watt amp, is a 30 watt twice the volume of a 15 watt, and a 60 watt twice the volume of a 30 watt ????
thanks guys for taking time to anwser this post,

all the best, bluesfloyd
Click to expand...

Nope that is not the way it works. It works logarithmically. That means 10watt is twice as loud as 1 watt, 100watt is twice as loud as 10 watt.

Maybe this site will clear up a little something for you
 
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Re: watts and volume

ok here is how it works roughly.
Every time you double the wattage, you increase 3decibels (db) in volume.
so 2 watts wil be heard as 3db louder than 1 watt thru the same speaker.
so, thru a speaker with 100db efficiency youd get this:
1w = 100db
2w = 103db
4w = 106db
8w = 109db
16w= 112db
32w= 115db
64w= 118db
128w=121db (roughly the same as a jet airliner passing directly overhead)

so speaker efficiency has a big part in volume. if you take the same wattages and run them thru a speaker with 97db efficiency you will get this:
1w =97db
2w =100db
4w =103db
8w =106db
16w =109db
32w =112db
64w =115db
128w=118db

what you get then with a 3db difference between the 97 and the 100db speakers is a requirement of double the wattage to get the same decibels in volume.
 
Re: watts and volume

And here's another site which has some redundancy to what the other posters have said, but adds a calculator and a chart to describe various sound levels. The stats quoted above are related to the standard speaker sensitivity calculations which are all taken at a distance of 3m. This calculator allows for varying that parameter as well.
http://myhometheater.homestead.com/splcalculator.html
 
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Re: watts and volume

gibson175 said:
ok here is how it works roughly.
Every time you double the wattage, you increase 3decibels (db) in volume.
so 2 watts wil be heard as 3db louder than 1 watt thru the same speaker.
so, thru a speaker with 100db efficiency youd get this:
1w = 100db
2w = 103db
4w = 106db
8w = 109db
16w= 112db
32w= 115db
64w= 118db
128w=121db (roughly the same as a jet airliner passing directly overhead)

so speaker efficiency has a big part in volume. if you take the same wattages and run them thru a speaker with 97db efficiency you will get this:
1w =97db
2w =100db
4w =103db
8w =106db
16w =109db
32w =112db
64w =115db
128w=118db

what you get then with a 3db difference between the 97 and the 100db speakers is a requirement of double the wattage to get the same decibels in volume.
Click to expand...

hi gibson175,
i have a 15 watt combo valve amp, the speaker is a g12m greenback, 25 watts, 16 ohms, 75hz, how do i know or find out the db efficiency of this speaker?????

all the best, bluesfloyd.
 
Re: watts and volume

Also, speaker efficiency and watts can be measured differently, further complicating matters. I've found it's really difficult to assess how loud acting is gonna be from specs. I had a Mesa Boogie 22 cal (20ish watts) that was way louder than my Crate vintage club 50watt ( through the same cabinet). Also, it seems with some amps that once the amp starts breaking up it stops getting louder and just get more distorted.
 
Re: watts and volume

Isn't the Crate a SS amp? There is also a huge difference in the rating and actual output of tube amps compared with solid state amps.
 
Re: watts and volume

bluesfloyd said:
hi gibson175,
i have a 15 watt combo valve amp, the speaker is a g12m greenback, 25 watts, 16 ohms, 75hz, how do i know or find out the db efficiency of this speaker?????

all the best, bluesfloyd.
Click to expand...
greenbacks are 98db according to the celestion website
http://celestion.com/product/16/g12m_greenback/
but gear in mind that different manufacturers have slight variances when it comes to how they measure their speakers and the gear that they use to measure it.
Also, different amp manufacturers measure their amp wattage differently. For example the original jtm marshalls are 35 watts...but that is 35 watts of clean (no clipping). They can pump out a lot more than that.


fwiw...greenbacks are pretty inefficient as far as guitar speakers go.
 
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Re: watts and volume

zoolion said:
Also, it seems with some amps that once the amp starts breaking up it stops getting louder and just get more distorted.
Click to expand...

Actually this is true of all amps. The power supply will ultimately dictate how much power an amp can put out (Watts). Of course other circuit parameters also play into the equation, but the power supply is the big one. Once the limits of the power supply are reached, the signal can only get more distorted, but not any bigger. This can be seen clearly by viewing the output of an amp on an oscilloscope.
 
Re: watts and volume

gibson175 said:
ok here is how it works roughly.
Every time you double the wattage, you increase 3decibels (db) in volume.
so 2 watts wil be heard as 3db louder than 1 watt thru the same speaker.
so, thru a speaker with 100db efficiency youd get this:
1w = 100db
2w = 103db
4w = 106db
8w = 109db
16w= 112db
32w= 115db
64w= 118db
128w=121db (roughly the same as a jet airliner passing directly overhead)

so speaker efficiency has a big part in volume. if you take the same wattages and run them thru a speaker with 97db efficiency you will get this:
1w =97db
2w =100db
4w =103db
8w =106db
16w =109db
32w =112db
64w =115db
128w=118db

what you get then with a 3db difference between the 97 and the 100db speakers is a requirement of double the wattage to get the same decibels in volume.
Click to expand...
Excellent post. Should be stickied IMO
 
Re: watts and volume

gibson175 said:
greenbacks are 98db according to the celestion website
http://celestion.com/product/16/g12m_greenback/
but gear in mind that different manufacturers have slight variances when it comes to how they measure their speakers and the gear that they use to measure it.
Also, different amp manufacturers measure their amp wattage differently. For example the original jtm marshalls are 35 watts...but that is 35 watts of clean (no clipping). They can pump out a lot more than that.


fwiw...greenbacks are pretty inefficient as far as guitar speakers go.
Click to expand...


hi gibson175,
it seems you do not rate the greenback speakers, what speakers do you rate and why???? if i swaped the greenback from my vox ac15hw what would you replace it with????
all the best, bluesfloyd.
 
Re: watts and volume

You'll have a better sound with a lower wattage tube amp running into more speakers than a high watt amp single speaker combo....

I'm assuming that's why you're asking. Nearly everywhere I've played, using a 60 Watt Fender Super Sonic was terrible. I could never turn the amp up loud enough to sound good. However, when using a little Fender Blues Jr., it would sound great at venues...

Currently, I have a Jet City 22H running into a 2x12 cab. It "sounds" louder than my 60 Watt Supersonic...
 
Re: watts and volume

bluesfloyd said:
hi gibson175,
it seems you do not rate the greenback speakers, what speakers do you rate and why???? if i swaped the greenback from my vox ac15hw what would you replace it with????
all the best, bluesfloyd.
Click to expand...
i like greenbacks. they have a really classic tone and have a lot of character. Kinda woody and woofy and low efficiency. They sound like the 60s.
They don't have much low end tho - they get that cone cry and flap about in the breeze (in open backed cabs). But that can be part of the charm. They dont have really clear treble detail either, but again - its perfect for that low-fi 60s tone. You literally cant get that same feel with modern speakers with big magnets and sensetive cones.
However - when it comes to the general eq curve of the greenback, i prefer the eminence private jack. Its warm but it has plenty of detail in the upper harmonic range. Its bass end holds together also which is something i generally go for. So what you get is a similar eq to greenbacks, but with the modern niceties of a speaker that is not working at its ragged edge. Better or not is subjective. I like it a lot, but it is a different sound to the sound of greenbacks and their character. They are a bit louder than greenbacks too. So for a 1x12 open backed amp the private jack is a clear winner - but its worth remembering that in a closed back quad, a quartet of greenbacks being beaten to hell by a marshall is a pretty damn cool sound.
 
Re: watts and volume

IME, the speakers used and the e.q. have a whole lot more to with perceived volume than the wattage of the amp. An efficient speaker and a trebly tone will make even a low-wattage amp loud as hell. And crappy speakers and a mushy tone will make even the most powerful guitar or bass amp sound not all that loud.
 
Re: watts and volume

Your MkIV will be the very first amplifier that sounds better with a single speaker instead of a bunch of speakers.
 
Re: watts and volume

JCM900MkIII said:
Your MkIV will be the very first amplifier that sounds better with a single speaker instead of a bunch of speakers.
Click to expand...

My MKIV will eat lunch box heads with 2x12's for... well for lunch...

I get it your dutch... but do you really want to argue.. better?
 
Re: watts and volume

I don't have one but have wondered about the Mesa Boogie 1 speaker combos. Have heard lots and enjoy reading the information so many have here about speakers and the whole technology. I know one thing for sure, this group brought to light (for me) the fact that my existing Fender bass cabinet with two 15" speakers (relatively large speakers in my opinion) would not sound as good as either the four 10" alternative or the one I ended up with, the eight 10" speaker cab. Nice difference. And while I keep the two 15" speaker cab on stage on one side, the one I mic up for the mains and the subs is the cab with the 10" speakers......what punch and clarity.

I have some combo amps with 2 speakers, and 3 speakers...but the only ones I have with one speakers are just those for smaller practice rooms (Roland cubes). On stage have only used the large combo amps....but never a high quality one with just one speaker like the Mesa Boogie. Very interested in the difference...........and also the discussion above that tube amp sound might improve with smaller amps on stage and not using the 40-100 watt size? Good info........thanks!
 
Re: watts and volume

No...

Speakers are what they call frequency directional.
Unless you have "special Italian" (FFS, what does being Dutch have to do with that, seriously?) speakers, yours work just like the one in this picture:

DSC00547.jpg


The higher the frequency, the more focused the sound.
Adding more speakers helps spreading those frequencies etc.
(Technically the same goes for microphones)


Well, that is what I got taught in the P.A. course I did a couple of years ago...
 
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