Amp volume and sound level question?

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PDP

There once was a note
If guitar player one is playing through a 50watt amp into two 25 watt speakers

and

guitar player two is playing through two 25watt amps each with a 25 watt speaker

are they the same volume?
(assuming they are the same type of speakers and amps at max volume)
 
I can't answer that question, but I know the wiring and impedance of the two speaker setup will make a difference, so maybe specify?
I think wiring the first setup in series would make all things equal.
 
Thanks,

For some reason I think the single 50watt would be louder, but if a 25watt speaker is getting its full 25watts and it cant get any louder, then the more 25watt speakers you add the more volume you should get. I guess?
 
I'd think so, although I expect Greg or Lt.Bob will weigh in and know for sure.
 
PDP said:
If guitar player one is playing through a 50watt amp into two 25 watt speakers
and guitar player two is playing through two 25watt amps each with a 25 watt speaker
are they the same volume?
Click to expand...

If two trains leave the station at the same time going in opposite directions...and train one is going 15 MPH faster than train two...........

:D
 
miroslav said:
If two trains leave the station at the same time going in opposite directions...and train one is going 15 MPH faster than train two...........

:D
Click to expand...

I did put it in the newbie section. The thread says no one will laugh at me :(
 
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It just reminded me of those funny math questions back in the early school days of my youth.... :D

I would think the 50W amp will be louder...even though there ARE two 25W amps, They are still only 25W.

It's like when you bring that new 50W amp to practice to show it off, and all you bandmates only have 25W amps....
....you'll be louder.

Of course, there's so much more to it than just the "numbers" of the wattage...so sometimes a lower wattage amp sounds louder.
 
Yeah, pretty sure an AC15 or AC30 will blow many 50 watt amps out of the water in terms of volume. Those suckers are LOUD.
 
PDP said:
If guitar player one is playing through a 50watt amp into two 25 watt speakers

and

guitar player two is playing through two 25watt amps each with a 25 watt speaker

are they the same volume?
(assuming they are the same type of speakers and amps at max volume)
Click to expand...

It depends on how you wire the speakers. In parallel the 50W amp will be 3dB louder than the two 25W amps. In series the 50W amp will be 3dB quieter. That assumes the amps have the same gain and the amps aren't overdriven or loaded with impedance too low to handle.
 
bouldersoundguy said:
That assumes the amps have the same gain and the amps aren't overdriven or loaded with impedance too low to handle.
Click to expand...

Note boulder's last bit carefully then check the spec for your gear. Two 8 ohm speakers in parallel will have an effective impedance of 4 ohms and try to draw additional current from the amp. Different amps are rated for different minimum impedances and, below that, they'll have an electronic heart attack and die.
 
Each loudspeaker is getting 25 watts.
Therefore by...SPL = 10x log W +S (where S is the speaker sensitivity in dBSPL/watt/mtr).....

Yes, the resultant SPL will be the same..BUT! This assumes that an amplifier actually dumps its watts into the speaker load? They don't. Two 16 R speakers in parallel will behave differently from a single 8 R (assuming a proper "match" in both cases.

I have assume we are talking valve output stages here? If two identical solid state "hi fi" amps were used (and the impedances adjusted accordingly) the loudness would be pretty much the same.

But actually measuring the power OUTPUT of a valve guitar amp is tricky enough. Measuring the power going INTO a speaker is virtually impossible! ( which is why many speaker sensitivities are quoted at Vin = 2.828rms which is nominally one watt into 8 Ohms)

But does the question have a practical source? In both cases there will be quite enough noise to annoy the punters.

Dave.
 
ecc83 said:
But does the question have a practical source? In both cases there will be quite enough noise to annoy the punters.

Dave.
Click to expand...

Thanks!

Yes, Using two amps gives the option of using stereo effects which can sound very cool, but before I would invest in a two amp system I would want to have an idea of the onstage volume. If a second amp only gives me a little fullness, I might have to just go for one bigger amp. But as Boulder says if its only a few db its workable.
 
ecc83 said:
Each loudspeaker is getting 25 watts.
Click to expand...

But under the OP's stated conditions (as I interpret them) each driver will not be getting the same power.

If the amps' power ratings are for the same impedance, say 4 ohms, and both are driving two 8 ohm speakers then the two 25W amps will be producing approximately half their rated output with the same input as the 50W amp, about 12.5W into each driver. So the one amp will be producing 50W and the two amps will be producing a total of 25W.
 
bouldersoundguy said:
But under the OP's stated conditions (as I interpret them) each driver will not be getting the same power.

If the amps' power ratings are for the same impedance, say 4 ohms, and both are driving two 8 ohm speakers then the two 25W amps will be producing approximately half their rated output with the same input as the 50W amp, about 12.5W into each driver. So the one amp will be producing 50W and the two amps will be producing a total of 25W.
Click to expand...

If he wires the pair of speakers in scenario A in series, then will both scenarios not just be 50watt into the same impedance?

Say one 50 watt amp into a 16 ohm speaker,
and two 25 watt amps each into an 8 ohm speaker?

Maybe it doesn't work like that.
 
Refine the question a bit so each speaker is dissipating 25 watts. The 'wattage of the speaker is superfluous (had to assume 'same speakers anyway) and how they're wired wouldn't matter.
 
But this is a silly way to think of guitar amps, worrying about a few dB and stereo effects.

If a tube amp is too big then it may be too loud when you get it working hard enough to make good tone. If it's too small then at least you can put a mic on it and get it into the PA. An amp that gets good tone at about the volume that blends with the drums is just right. A Blues Jr. can do that with most drummers, and if it comes up short put a mic on it.

Fancy stereo effects will add more hassle than entertainment. I'd stick with one amp and let the sound guy pan it to fit the mix, assuming the PA isn't mono.
 
I heared NASA spent god awful $$$$ working out zero g pens.
Soviets just gave'm pencils!

Is that a true story?
 
PDP said:
If guitar player one is playing through a 50watt amp into two 25 watt speakers

and

guitar player two is playing through two 25watt amps each with a 25 watt speaker

are they the same volume?
(assuming they are the same type of speakers and amps at max volume)
Click to expand...

That question is unanswerable. There are too many other factors. At it's most basic level, I would think the two 25 w amps will seemingly be louder than one 50w amp. Why? It's two amps! Two loud sources is louder than one loud source. Forget about the speaker wattage. That has nothing to do with loudness. The ohm ratings don't matter either. I assume we're talking tube amps, so if you match the amp to the cab load (you better), there is little to no difference between 4, 8, and 16 ohms. What really matters is the speaker's efficiency if you're talking brute loudness. For example, you can have your two 25 watt amps and two cabs. I'll run my 50w amp into a cab loaded with very efficient speakers and blow your face off. With all things being equal, my 2x12 with Vintage 30s is noticeably louder than my 4x12 Greenback/G12-65 cab. Two less speakers, but they're more efficient, so it kicks out more volume with the same amp settings. Wattage and ohms don't matter. The Vintage 30 is a louder speaker than my Greenbacks or G12-65s. So even two less of them is louder.

That's my take on this shit anyway. Personally, I'd rather have too much amp. Headroom matters.
 
It's perfectly answerable. It's just that like that '..you know the ultimate question? Life, the universe- everything..!'
You have to ask it right.

Otherwise ..it's hmm.. tricky

But I'm with you on one point. Two is one more
And that = 'more' :D
 
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