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wattage vs volume

7/23/2000 4:07 AM
Gord wattage vs volume
I've been wondering, exacltly how much louder is a 200w amp than a 100w amp? In some previous thread I read that a 600w amp is double the volume of a 60w amp. Is this true? Is there some kind of mathematical equation to help me figure this kind of thing out?  
The reason I'm asking is because my brother, who plays bass guitar, wants to buy a Traynor Custom Special, and throw in four Svetlana 6550 tubes, to get around 200w. I told him that a Bassmaster Mk2 with two 6550 tubes, about 100w, would be loud enough, and much cheaper, but he thinks that this would only be half the volume. How much louder is the one amp over the other really?  
7/24/2000 4:55 PM
A 200w amp is about 3 decibels louder than a 100w amp because it is twice the wattage. A 600w amp is 10db louder than a 60w because it is a little more than three doublings of power. Therefore a 120w amp would be 3bd louder than the 60w, a 240w amp would be 6db louder than 60w, and a 480w amp 9db louder than 60w.  
Of course none of this means anything unless you have some idea of what a 3db or a 10db increase actually sounds like. If you had never seen a speedometer in a car before you could probably guess what "fast" is but would you have any understanding of the scale in MPH? not really. The only way to get a feel of the scale is to drive and look at the speedometer, think back to when you first learned to drive and had no idea of the relation of apparent speed to actual MPH, you have to learn the connection and then it becomes somewhat second nature. The same is true with sound the difference being that most musicians have no idea of the scale involved, they have never used a decibel meter, and decibels unfortunately remain an unknown and "unusable" bit of math.  
Should an amp with two 6550's be enough? It probably should be more than enough in most cases but I have no idea what he or the other guys he plays with think is a good level. Many people play at such a high volume that an amp with two 6550's with a couple of 15's or 4x10's for bass would be having a hard time and 3db, although not much, might be the difference in being "heard" or not.
7/24/2000 10:24 PM

This is called a log function  
(yes you remember them from high school) :)  
log 10 = 1  
log 100 = 2  
log 1000 = 3  
repeat ad nauseum  
so 1000W is 3 times louder than 10W.  
Of this is all shit when efficiencies of speakers and other all to important factors are not factored in.  
a 100W marshall full stack is more than twice as loud as a princeton IMHO, but this has to do with the speakers, and the shear amount of air that is being moved. If both were played through the same speaker setup, all things the same the log rule should hold.  
FWIW -- there is no such thing as too much power in a bass amp. 100W is really not that much, and the extra headroom in a 200W amp will be much welcomed by just about any bassist.  
7/25/2000 9:40 AM
Stephen Conner

"FWIW -- there is no such thing as too much power in a bass amp."
I agree. Unless you're in some kind of acoustic jazz band, bass is all about getting the floor shaking, teeth rattling, things falling off shelves two blocks away, etc. I'm building a 600 watt bass amp just now (solid-state power section for cost reasons)  
Steve C.
7/25/2000 11:10 AM

Stephen, et al,  
Not to start a flame thread (please) but I respectfully disagree. I absolutely abhor feeling the pectoral muscles of my chest vibrate with a bass note - it's an amazingly disconcerting effect and seems to trigger something that is within shouting distance of a panic attack (have never actually had a panic attack from it - just dis-ease). More and more frequently I have left performances due to this effect and I attribute it to just too much available power in the hands of bass guitarists (damn transistors). Sorry but I prefer my bass to be sonic, not geologic.  
Again, with respect,  
7/25/2000 2:45 PM
Stephen Conner

"More and more frequently I have left performances due to this effect and I attribute it to just too much available power in the hands of bass guitarists"
I agree, but I'd be more inclined to blame the soundman who will have maybe 4kW of subwoofers at his command in a decent-sized venue. Personally, I enjoy the bass but I find the levels of mids and treble agonizing to the point that I've started wearing earplugs to concerts. I think the main problem is that they are just too damn loud, period.  
Steve C.
7/25/2000 3:49 PM
I'm gettin' in here w' GW on this one!  
I sacked my SVT because it was too clean at a reasonable volume. I find the 100 watts of my v-4B to be perfect for my uses (w/efficient speaks). If clean is a big goal - go to the 1/5 Kw+ range.  
I like nice tight tough sounding bass with some breakup when you hit it hard, the "touch - sensitivity" that Guitarists are always on about.  
YMMV, of course.  
- A
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