What's the point of 100 watt amps?

[Eric***]

Man, lot of good info in this thread! IMO, it's mids that provide the punch to cut through for bass or guitar. Lose mid frequencies on both (like a lot of metal bands do), and it can become a woofy, mushy mess. Then, a band will compensate by turning up the volume on the 100 watt (or more for the bass) stack, creating a loud, woofy, mushy mess that becomes a roar of nothing but noise.

It's funny, 'cause at times I like big giant messes of sound, like in some...well, I'm not sure what they're considered (Black Angels, Darker My Love)...bands. I love the sound of the Big Muff on Siamese Dream by Smashing Pumpkins, but that's the whole point of that pedal.

Anyway, I don't know if I have a point. I guess it's just that if you're actually going for a big fizzy mess a la fuzz tones, I think it can be pretty sweet if done right. But I know that wasn't really your point.

[Ch0jin]

...... I had no idea that the response of the ear to the frequencies of sound, and the SPL too I suppose, has such an affect on the sound we perceive; as opposed, I guess to the actual sound wave pattern generated by the amp and speaker and pushed thru the air. It sounds like what we hear is regulated by our human condition;

If you enjoy mulling that concept over in your mind, consider that the exact same situation occurs with what we see. I'll be brief cause it's wildly OT, but light is also a wave (yes I know it can also be a particle, but leave that out for now). When we look at a something, the colours we "see" are in reality just our brain interpreting the eye's response to different frequencies. Blue is not "Blue". Blue is what our brain comes up with when our eyes are hit with a frequency of around 650THz.

Think about that for a while.

I have some info around the rest of your post too, but work beckons. I'll get back to the physics lesson later

[NWBasser]

I was also wondering about why bass can be muddy, which might be part of that same discussion. I used to own a 50w Crate amp where it was bass all over the place unless you turned the EQ knob off completely, but it was wild and boomy bass -- not something I'd want in a band or even on my own.

My experience with Crate bass amps is that they're not very well voiced (being polite here).

However, the boomines that you describe may well be the result of boundary effects in the room.

Bass can be a female dog to EQ and amplify correctly due to standing waves, reflections, phase cancellations....

[deeaa*]

One thing that can have an unbelievably strong effect is also wall proximity, both behind the amp and in front. Bass waves have such a long wavelength that they literally aren't audible in spaces smaller than the frequency demands. Also guitar amps, particularly open-backed Fenders etc. can sound drastically different when placed against a wall/in a corner; especially crunchy sounds can change totally. Battled with these issues a lot gigging in very small venues back in the day, both as a bassist and guitarist.

[NWBasser]

One thing that can have an unbelievably strong effect is also wall proximity, both behind the amp and in front. Bass waves have such a long wavelength that they literally aren't audible in spaces smaller than the frequency demands. Also guitar amps, particularly open-backed Fenders etc. can sound drastically different when placed against a wall/in a corner; especially crunchy sounds can change totally. Battled with these issues a lot gigging in very small venues back in the day, both as a bassist and guitarist.

This is a common misconception. If it were true, then you wouldn't be able to hear any bass in headphones.

The idea that bass waves take space to develop is false. What actually happens is that in a certain point of a room you may get phase cancellations from room reflections leading to the false idea that more space is needed for the sound wave to "develop". The bass sound waves are fully developed right at the speaker.

[Duffy]

My thinking is that low frequency bass wavelengths such as those produced by guitar and bass amps are many feet long for one full wave. How this corresponds to how we perceive the bass sound in a small room or from headphones, I'm not sure. Of course, not being unidirectional, a lot of the waves are not going to have the space to fully form their waves before being reflected and atenuated. They are bouncing all around at high amplitudes reinforcing each other and cancelling each other out.

Here are the frequencies and wavelengths for the strings on a 4 string bass +/-:

String – Frequency - Wavelength
G - 97.9989 Hz - 11.531 ft.
D - 73.4162 Hz - 15.392 ft.
A - 55.000 Hz - 20.545 ft.
E - 41.2035 Hz - 27.425 ft. (329.098 in.)

The above wavelengths will occur in a free space, a space free of obstructions, walls, ceilings, people, etc.

Since our amps are located near walls, have open backs, are in enclosed rooms, etc., there are going to be a lot of powerful high amplitude sound waves bouncing around reinforcing each other and cancelling each other out, as the case may be in any given space. This is what I think Dee is talking about - the situation where you have sound waves bouncing all around and affecting what our ears perceive. Therefore, experimenting with the placement of the amps and speakers, aiming, etc., can have a big effect on how we hear our music. Because of this recording engineers go to great length to try to deal with this problem and the bass frequencies are particularly problematic for them and they go to great length, in some cases, to try to get it right or at least "better" sounding.

Also, it is seemingly confusing why we can hear a 40HZ bass note correctly thru a set of earphones. The amplitude of the sound wave at 40HZ coming to our ear from the headphones is much lower than the amplitude coming out of a bass amp. But the wavelength is still about 27 feet long, so our ears and brains must be processing that E note somehow so that it sounds right, even if the note is very short in duration such as one tenth of a second - it still sounds right.

[deeaa*]

Exactly. You can hear bass in headphones quite OK, but that's a completely different experience from hearing the actual waves in a space where they have room to function...proper low bass will literally cause your heart to try to adjust to its beat...in headphones it's just a faximile...you know this of course from how in a large space a real strong bass will make you literally weak in the knees, even in an orchestra concert...thus any proper mastering studio will be deep enough to allow for true bass reproduction. And yes, the bouncing waves have everything to do with it, it's a science on its own to adjust a room to portray true frequencies as they are...not an easy task.

[Bookkeeper's Son]

..you know this of course from how in a large space a real strong bass will make you literally weak in the knees.......

Are we going to start debating the "brown note" now?

[NWBasser]

...a lot of the waves are not going to have the space to fully form their waves before being reflected and atenuated.

Actually, the waves are fully formed right at the speaker (electro-mechanical to acoustic energy transfer). For a sound wave to gain amplitude (i.e., fully form) in free space, it would need some sort of energy input.
Sort of like when a bullet exits the barrel of a gun, it's going full velocity at that point and it won't speed up in the air on its own accord.

However, like a bass wave, a bullet can ricochet around and do all manner of odd things. But it certainly won't be going any faster.

[Duffy]

I think the frequency and the wavelength of a 40HZ bass note will remain the same no matter what. The wave will not move faster, that would change the frequency - the number of cycles the wave makes per second. The frequency of a bass E note is always going to be about fourty cycles per second and the wavelength is going to always be about twenty seven feet long. What changes when we add more energy to the speaker, watts, is that the amplitude of the waveform increases.

It might not seem to make sense, but frequency (cycles per second), wavelength, and the third component of a waveform - amplitude are involved. The amplitude is the variable that changes and makes the sound louder. Frequency and wavelength of a given note remain the same. In order to increase the amplitude there needs to be an increase of power at the speaker to make it louder.

For the sake of discussion this is interesting, but for all practical purposes it may or may not be of interest to a muscian, and definitely is not necessary to know in order to be among the best of muscians. It's kind of like noisy single coils - some muscians like them and some don't, and the reason why they are noisy doesn't really have anything to do with why a musician may have a personal preference. I'm sure there is more to the whole equation and what it means to how we hear sound, way more than I know.

For some people 100 watt amps intuitively sound great and others don't like them. You can turn them down or turn them up and satisfy just about anyone. And like Eric suggested, some muscians may not have any need for a 100 watt tube amp.

[Katastrophe]

It's funny, 'cause at times I like big giant messes of sound, like in some...well, I'm not sure what they're considered (Black Angels, Darker My Love)...bands. I love the sound of the Big Muff on Siamese Dream by Smashing Pumpkins, but that's the whole point of that pedal.

Anyway, I don't know if I have a point. I guess it's just that if you're actually going for a big fizzy mess a la fuzz tones, I think it can be pretty sweet if done right. But I know that wasn't really your point.

You're right, in the right context, that "amp is about to explode fuzz sound" can be pretty cool. There are a few Smashing Pumpkins tunes that I dig for that very reason... Here's a "wall of sound" recording that I think they used some half stacks to good effect:



Note that the bass plays simply, but there would definitely would be something missing if he wasn't there.

[Eric***]

You're right, in the right context, that "amp is about to explode fuzz sound" can be pretty cool. There are a few Smashing Pumpkins tunes that I dig for that very reason... Here's a "wall of sound" recording that I think they used some half stacks to good effect:

Note that the bass plays simply, but there would definitely would be something missing if he wasn't there.

That was pretty neat. Thanks for the link.

[cebreez]

Its all about the physics. In the studio you can dub and over dub, pan and fade, or double and delay to your hearts content but it will take some effort on the engineers part to recreate that massive air'ish feedback sound. Even onstage if you mic a small amp it will still sound like a small amp to the mixer. But set a mic in front of a large stack and it will sound like a large stack as it pushes volumes of air and sound towards and around the mic. Just because you point a mic at one speaker doesn't mean thats the only speaker it will pick up. My only point is small amps sound small and big amps sound big. Sounds stupid I know but I love my Peavey Classic 30 112 and the tone I get but sometimes my buddies 212 sounds so much larger even if mine is louder.

[Ch0jin]

Are we going to start debating the "brown note" now?

Myth Busted. I saw the episode where they tried it.