Number of speakers related to volume?

rsf1977

Fractal Fanatic
If you have 2 4x12 receiving 100 watts each how does that compare to a single 4x12 receiving 100watts if the cabs are identical. Basically, how does adding more speakers at the same power rating add to perceived volume?
 
First off your moving more air with a pair of speakers so logic dictates if you take half of the air movement away you will have less volume.

Another good question is if I had 100 speakers in a room and only feed them 1 watt each would it be the equivalent of 1 speaker being powered with 100 watts?
 
Sixstring said:
First off your moving more air with a pair of speakers so logic dictates if you take half of the air away you will have less volume.

Another good question is if I had 100 speakers in a room and only feed them 1 watt each would it be the equivalent of 1 speaker being powered with 100 watts?


I hope someone can answer this question cos i've always wondered about that too. It must tho because if you use this analogy:

If you have someone banging a hammer on a wooden post and you stand back say..1000 meters away, your gonna hear the bang (albiet with a delay - light travels faster than sound stuff)....however if you had 100 people banging a wooden post with the same force, surely your gonna hear it much 'louder' even tho they are all banging with just the same power/force as one person :geek:
 
won't it be 3dB louder?

quote from one of the top Bose engineers

"There is a well-established body of research on loudness perception and that shows clearly that (at sound pressure levels of about 50 dB SPL and above) you need 10 dB to double the perceived loudness. To get four times as loud you need to add 20 dB.
"

Jay will likely know
 
Hearing is not on a linear scale, so it won't sound twice as loud. It's actually on a logarithmic scale, so it will only sound a little louder (i.e. 3 dB if I'm not mistaken). And I think you would need 10 times your setup (ten 100-watt amps feeding ten 4x12s) for it to sound twice as loud? That sounds like a lot... at least on paper, that's what's needed. Of course, reality is usually different than paper... also I think my log scale theory applies to power, but not necessarily to additional speakers moving more air...
 
You don't get something for nothing. There's no difference with 2 x 50 watts vs 4 x 25 watts, it's all 100 watts.

There IS a perceived difference when you stand next to your speakers and you have additional speakers closer to your ears. For example, 2 x 12 blasting past you kneecaps is not as loud as 8 x 12 where you have some speakers at ear level. But far enough away it doesn't matter.

The 10dB difference for double volume is technically correct, and something I've had on my own web pages for over 15 years, and yet it has been challenged by some audio professionals who have claimed figures as low as 6dB are double volume. :? In any case, you need a lot more than double power for double volume. But here, we're talking about amplifier power, not speaker handling capacity. Adding more speakers doesn't make you amplifier more powerful.
 
Since you are doubling the output power there will be 3dB rise in output... all things being equal... in theory...

The perceived volume rise is tricky since the output is now spread over twice the area, guitar speaker cabs tend to beam and you lose 6dB per doubling of distance from your ear* - but depending on the room there will be an increase in reflected sound level... so it will sound different... and louder... a bit.

(*assuming a spherical wavefront - which a guitar speaker almost certainly doesn't produce...)
 
vinnieRice said:
Since you are doubling the output power there will be 3dB rise in output... all things being equal... in theory...
Doubling the speakers does not double the output power. Presumably, you're setting your amp's output impedance to match the speaker load to get maximum (and the same) power output into either 2 or 4 speakers?

Yes, if you use a second amp to power the additional speakers with the same power as the original speakers, then there will be a 3dB increase.
 
GM Arts said:
vinnieRice said:
Since you are doubling the output power there will be 3dB rise in output... all things being equal... in theory...
Doubling the speakers does not double the output power. Presumably, you're setting your amp's output impedance to match the speaker load to get maximum (and the same) power output into either 2 or 4 speakers?

Yes, if you use a second amp to power the additional speakers with the same power as the original speakers, then there will be a 3dB increase.

Did you read the original post? "2 4x12 receiving 100 watts each"....
 
I agree with the "perception" argument. Based on what I perceive, my single 4x12 does not "sound" as powerful as both of my 4x12's running at the same time, even if I crank the volume higher on the single 4x12. This is with both cabinets sitting on the floor. The most noticable difference is in the lower frequencies.
 
vinnieRice said:
GM Arts said:
vinnieRice said:
Since you are doubling the output power there will be 3dB rise in output... all things being equal... in theory...
Doubling the speakers does not double the output power. Presumably, you're setting your amp's output impedance to match the speaker load to get maximum (and the same) power output into either 2 or 4 speakers?

Yes, if you use a second amp to power the additional speakers with the same power as the original speakers, then there will be a 3dB increase.

Did you read the original post? "2 4x12 receiving 100 watts each"....
Thanks Vinnie - I overlooked that. I stand by what I wrote, including: Yes, if you use a second amp to power the additional speakers with the same power as the original speakers, then there will be a 3dB increase.
 
Back
Top Bottom