How Watts relate to volume.

Replies to This Discussion

Permalink Reply by Chris on November 11, 2009 at 4:59am

I only know simple things about electronics, but I know that the increase in wattage does NOT give proportional increase in volume.
A tube amp generally makes a lot more volume than a solid state amp. Most acoustic amps are solid state.
My Fender Pro Junior (tube) amp is 15 watts and really gets loud. I've never turned my Peavey tube amp (50W) all the way up. My Fishman acoustic amp (original 250W Loudbox) also gets pretty loud, but not in the way the tube amps do.

▶ Reply to This

Permalink Reply by Ben Hagstad on November 11, 2009 at 7:04pm

Are tube amps better or is it one of those situations where each kind of amp has pros and cons? What are the differences between tube and solid state amps? What Peavey amp do you have? I was actually looking at a Peavey KB 2 (50W)

Thanks

▶ Reply to This

Permalink Reply by Newbie Dean on November 11, 2009 at 8:23am

As a retired engineer, I worked with sound and vibration equipment. The "watt" is a unit of power. If your amp has a low efficiency sound system (speaker and resonator box), the more of that wattage is used up in that inefficiency so the volume is lower. If your amp has a good efficiency speaker and resonator box, it will take less of the wattage to drive the speaker and allow higher volume. A good example is an acoustic guitar. Some project sound very efficiently and sound LOUD while others are not as efficient and the sound is muted.

▶ Reply to This

Permalink Reply by Charles on November 11, 2009 at 2:58pm

From one retired engineer to another retired engineer:
A good description on why some amps sound louder than others. Also applies to radio antenas and transmitters. Although I was aware of this phenomenon I never made the analogy to the the guitar....or any musical instrument for that matter.
Yours is a point well made!

▶ Reply to This

Permalink Reply by Newbie Dean on November 12, 2009 at 7:38am

Thanks.....An aside to this is the fact that the human ear senses sound "intensity". Certain frequencies are "heard" louder than others. So, unless you are using a db-meter, it is difficult to compare the sound "volume" from a variety of speakers where some may be biased to high frequencies (treble) and others to low (bass) frequencies. So, I guess, when choosing an amp for "volume" output, you may want to pay attention to the "sound" you want the amp to project.

▶ Reply to This

Permalink Reply by Charles on November 12, 2009 at 12:45pm

Yes....the type sound does make a difference. As an example, all RAP or distorted HEADBANGER music sounds way too load to me at any power level! ; )

▶ Reply to This

Permalink Reply by Teja Gerken, Senior Editor on November 12, 2009 at 4:57pm

Wattage alone doesn't tell you very much about actual volume of a guitar amp. Besides being only one spec among a system of components that lead to the final sound, some manufacturers also rate their products more optimistically than others. Even among acoustic amps, I've heard 60-watt amps be WAY louder than another brand's 175-watt amp, so you really have to listen to the amps you're considering yourself, or at least talk to someone who knows a particular model in order to get a sense of what you're getting--reading specs alone won't get you there.

Another thing to consider is that not every amp necessarily works with the same type of input signal. Some amps need a pretty hot signal coming from the guitar or an external preamp to be able to develop their full volume potential, while others are more flexible in that regard. If you're finding that you can turn the volume control of your amp all the way up without running into distortion, chances are that your signal is too weak for the amp. Using an external preamp can make a huge difference in those cases, usually leading to better overall tone as well.

▶ Reply to This

Permalink Reply by Brian McHale on November 13, 2009 at 12:03pm

There's a lot of good advice here. One thing I don't think I read, however, is the actual relationship between power and volume. Generally speaking, all else being equal, it takes about 10 times as much power to double the perceived volume. So, assuming the speaker and everything else is the same, a 150W amp would be twice as loud as a 15W amp.

However, as already pointed out, there's a lot more to it than just power.

As far as tube amps generally being louder than solid state, I wonder if that isn't because tune amps can run into distortion and still give a usable tone, whereas solid state sounds awful when it distorts. That's why tube amps are popular for electric guitar, where some (and maybe a lot of) distortion can be a good thing. Most other applications, however, want as clean a sound as possible. That's why acoustic amps and PA systems are almost always solid state: they just don't have that much to gain from using tubes.

▶ Reply to This

Permalink Reply by Teja Gerken, Senior Editor on November 13, 2009 at 12:24pm

Some of this tube vs. solid-state volume may be due the clean vs. distorted tone, but I think some of it is also due to the other variables already discussed. I have a 50-Watt Mesa/Boogie DC-5 that is probably has a louder clean tone turned to about "3" than my 60-Watt AER Compact 60 has when cranked to its limit. The AER, in turn, is the amp I referred to in my earlier post about it being perceived louder than another amp rated at 175-Watts; it's really a difficult game to make these calls...

▶ Reply to This