What Makes Guitar Amps So Loud?


Have you ever wondered why a 100W guitar amplifier makes much more noise than your home stereo that exceeds 1000W?

Or why all of a sudden some amplifiers are heard so loudly, filling the entire room with sound?

What, in general, makes an average guitar amp so loud?

The volume of many amplifiers is not linear. This means that they can go from being “barely audible” to “too loud” just by taking a breath on the volume knob. Also, many amps are designed in a way that they operate the best only when you crank the volume knob all the way up.

So, many amplifiers must operate at a certain volume level to achieve the desired tone and distortion. In the case of high power amplifiers, these are designed only to handle high volumes and they don’t sound properly until they are pushed to higher limits.

The truth is that, in an ideal world, the sound of a guitar amplifier would remain the same from very low to very high. Without distortions and without being perceived as “louder” when reaching a certain volume level.

But, our ear does not hear the same at different volumes and frequencies. We are not going to expand on that topic now, but you can look for the Fletcher-Munson curve (Wikipedia) to read more about it.

The important thing is to know that it doesn’t matter if your amplifier is solid/digital or valvular. It will simply sound much better at a slightly higher volume.

But Now … What Exactly Makes an Amp Loud?

Well, there are a variety of things that come into play here. But, for reasons of comfort, people often erroneously compress all these variables into a single number: wattage.

In this article, we are going to elaborate a little more about what other aspects make an amplifier sound loud.

Do More Watts Equal More Volume?

It is a typical doubt: more watts = more volume?

Well, in a nutshell, no.

While it is true that the power in watts is the most consistent way to classify an amplifier, only with that data we cannot guide ourselves to know how loud it will sound once we are using it.

It is not an accurate and reliable measure.

People tend to simplify things, but there is a fairly general confusion when discussing this issue.

When it comes to buying equipment, many potential buyers, or even musicians, just pay attention to the power of the amplifier, assuming that more watts equals “more volume.”

  • while it’s true that power plays an important role, speaker efficiency often turns out to be a more fundamental factor in the volume equation (and we tend to set it aside)

But, before seeing in detail all the factors that can affect the loudness aside of the wattage, let’s clarify exactly what we mean when we say “volume” or “loudness”:

Decibels and Volume Levels

How can we say, with a number, how intense a sound is?

Well, the decibel (or dB for short) is a physical quantity formulated to classify volume levels.

It is a logarithmic unit of measurement that arises from the relationship between two numbers. I understand, as I can see how you are spinning your eyes on this comment, so we better simplify things and try to keep “math” at an absolute minimum.

If we refer to a logarithmic scale, we can no longer say that the numbers are added in the usual way. This means that a duplicate number is not just the twice of the previous number. On the contrary, it means that it is many, but many times higher.

With this in mind, believe me when I tell you that 90dB is many times larger than 45dB. It is not just “double.” That means there is no comparison between those two levels of sound.

There must be a difference of 10dB to get exactly twice the sound. So if one amplifier is delivering 80dB and another amplifier reaches 90dB, the second will be perceived with twice the intensity for the human ear.

A little example of Watts, power, and loudness.

With all of the above in mind, you may ask: How many watts are needed for my amp to be twice as loud?

Well, to give an example: suppose we have a 10-watt amplifier and another, the same in all aspects, but with 20 watts of power.

It’s clear that one doubles the other in terms of power; but that 10 W difference will only generate a 3 dB increase in the final volume.

And let’s not forget that for one to sound “twice as high”, we need an increase of at least 10 dB with respect to the other.

So, while a 20 W amplifier will sound considerably louder than another of 10 W, this difference will not be double.

This relationship is maintained even for higher powers, therefore neither a 100 W equipment will sound twice as high as a 50W one.

Again, assuming the speakers are identical, it will only be 3 dB higher, which is not negligible, but strictly speaking, it is not a doubling of the perceived volume.

Other Things That Affect the Volume

We have just seen what the impact power (wattage) has on decibels. However, there are other things that contribute to the dBs and make amplifiers sound much louder, such as:

Compression

When we talk about compression in audio, we are essentially talking about an automatic volume or level control.

They are the equivalent to the fader of a console operated by a person in real-time. That person has the function of lowering the fader when the volume of an element suddenly rises in excess.

All this to control the dynamic range of said element and prevent it from leaving the range. So, what the compressor does, in essence, is to reduce the level of a signal with parameters that are set by the user and that modify how it behaves.

All this is to avoid distortion in the face of an abrupt change in volume.

  • valve amplifiers usually have a high compression, which helps them to get a good volume instead of a large distortion.

Speakers

The size, quality, quantity, and impedance of the speaker play an important role here. All these aspects have a determining effect on the final volume of an amplifier.

Every amplifier has a characteristic impedance value (its internal resistance to the passage of electric current).

We always want that impedance to be exactly equal to that of the speaker that we connect. In this way, the amplifier can deliver all its power (if you don’t trust my word 😉 or you’re curious about it, you can search for the maximum power transfer theorem on Wikipedia).

In many cases, these impedance values may not match and this is fine to some extent, but it won’t probably sound as strong as it could.

We should also know that the more expensive a speaker will generally have superior quality, a better transfer, and a much stronger sound.

This has to do with the efficiency with which the speaker transforms electrical energy into mechanical energy. A cheap 12″ speaker generally has a power of approximately 93 dB. And an average price speaker can exceed 97 or even 100 dB.

Projection/Dispersion

There are other variables, such as projection and dispersion: The more speakers we have in an environment, the more air they will push and the perception of the sound will be stronger.

Are Valve Amps Louder Than Solid-State Amps of the Same Power?

The answer is no. However, they do “sound” louder. Yes, I know it’s confusing, so let me explain:

Recently, some excellent scientific works on tube preamps and their distortion effects managed to explain the reason for this phenomenon.

When the tubes are carried to the borders of their linear region, in the first 12 dB of saturation, they produce certain harmonics that deceive our ear into thinking that these sounds are actually louder than they really are.

This acoustic trick can make valve amplifiers sound up to 12db more than they are actually emitting when compared to a perfect and distortion-free amplifier.

The truth is that, in a solid-state amplifier, distorting at the same level as one of with valves, we would listen to the distortion as just what it is: some weird sounding noise.

But in valve amps, due to the effect of these harmonics, the same level of distortion will only be perceived as a louder sound.

In short: No, they don’t have more decibels. But yes, we do perceive them louder than they really are.

If you want to know more about it, check the study: The warm, rich sound of valve guitar amplifiers published online on IOPScience.

Conclusion

I hope this article gave you valuable information and insight about this topic.

Wattage isn’t the only important measure. As it’s been stated above, there are lots of factors that affect the volume of an amplifier or speaker, and that is an important fact to take from this article.

While power is a good, simple, and concrete number to take the first look, it is not completely reliable. Keep all these things in mind if you are looking for a perfect amplification solution.

Also remember, a valve amplifier will sound naturally louder than a similar solid-state amp due to compression and its particular distortion, but this is only because they deceive our ear; they don’t actually make more noise.

Check Out Some Cool, Affordable Amps For Yourself

Feel free to visit the article from this site where you can find the list of the best affordable amps for yourself.

Also, don’t forget to visit other articles from this page about various guitar topics and issues!

Cheers, and rock on!

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