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Question about power upgrade

No, it won't be twice as loud. You'd need 10 times the power, or 10 times the efficiency, or some combination thereof, to achieve that.
Right, if he was only increasing wattage. Did you check the stack he was talking about, Richard? He's more than doubling speaker area (and supplying at least as much wattage to each cab as he was to the single 15). That's what I was basing the prediction of twice as loud (perceived) on.
 
Originally posted by Joe_Atlanta
Right, if he was only increasing wattage. Did you check the stack he was talking about, Richard? He's more than doubling speaker area (and supplying at least as much wattage to each cab as he was to the single 15). That's what I was basing the prediction of twice as loud (perceived) on.

You're right, there should be a pronounced difference in acoustic output; we only differ on how big a bump it's likely to be. I think "at least twice as loud" is optimistic. In part because even though adding speakers is a great way to increase output, you still have to take the efficiency of the speaker into account. If his two new cabs are less sensitive than his old one, he may gain little or nothing in the way of volume from adding speakers. For example, you can find plenty of 1-12s that would be more efficient and thus louder with the same power than my Acme 2-10, despite having less speaker area. However, if his new cabs are *more* efficient, AND he doubles his wattage, then maybe he could get to a 10 dB gain.

But enough of my quibbling; the main point is that yes, the new rig should be noticeably louder. Whether it's loud enough is up to the player and his particular situation.
 
Watts and decibels aside... You will hear a big difference in volume by adding a 2x10 to your combo.

Adding speaker area is the most successful way to add volume - Much moreso than adding wattage - taking of into consideration the volume level we're talking about.


Whether the appreciable volume increase will be enough for your playing situation, setup, or playing style is tough to say. If you're 'almost' loud enough now...it should do the trick.
 
You have to take the efficiency of the speaker into account
Good point and as a fellow Acme owner I am quite aware of it. :(

My assumption was that similiar cabs from one manufacturer would be very close in efficiency. Wrong! Apparently this is not the case with the larger companies who have "families" of cabs (and goes to show I've been spending most of my time reading specs at the "boutique" suppliers ;) ).

I couldn't find any sensitivity data for the combos. However, in checking the GK cabs I found a huge claimed difference (10db!!!) between their high power (RBH) line and the rest of their cabs (RBS and BLX).

In Eskimo's case, it looks like they are pairing a RBS 1X15 with the 400mb 2X10 (the recommended pairing on the GK site). The RBS cabs do have the same sensitivity rating as the Backline series, so he should hear a big boost in volume.
 
how exactly does the sensitivity work?
It's a way of measuring speaker (and cabinet) efficiency, how well it turns watts into sound pressure. When comparing two similiar cabs, the sensitivity rating can tell you if one will be louder than the other. Note that a 3 decibel (dB) difference is generally considered to be perceptible by human ear as louder. To make up for that 3db difference you need twice the watts!! 5dB is noticeably louder and a 10dB difference is perceived as twice as loud.

"Sensitivity ratings are derived from the sound level produced by a speaker when fed a 2.83 volt input signal (equivalent to one watt of power into an 8 ohm impedance) with the sound pressure measured from one meter." from:
http://www.audiovideo101.com/learn/knowit/speakers/speakers22.asp

Another good explanation along with how to figure out the maximum loudness if you know the sensitivity and the RMS rating of a speaker.
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BTW, its a 2x10, not a 2x12.
Nice catch, I've edited my post to the real spec.
 

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