Do empty vessels make most noise?

Subject: RE: Do empty vessels make most noise?
From: Ebbie
Date: 14 Dec 12 - 03:45 PM

A scream in an empty hall sounds louder than one in a filled one. Therefore, thus and so.

Subject: RE: Do empty vessels make most noise?
From: Mysha
Date: 13 Dec 12 - 05:28 PM

(Hi,

Yes, U think there is. I seem to recall a hi-hat-like instrument that lifts the top when the pedal is pushed and let's it fall back on release.

Bye,
                                                                Mysha)

Subject: RE: Do empty vessels make most noise?
From: Mysha
Date: 13 Dec 12 - 05:02 PM

Hi,

As to the relationship between emptiness and quality of sound, I'd expect that the quality is probably in the ear of the beholder.

The volume of sound, would seem a matter of energy: By some means you put energy into the vessel, be it by blowing, by plucking, by hitting or by swinging round (did I miss any?), and the energy either heats up the instrument, comes out as what we recognise as sound, or comes out as a form of energy we don't consider sound. If we keep playing an instrument, it's probably not possible to keep heating it indefinitely; eventually all added energy must come out, and one form of that we consider sound. Does the content of the vessel influence how much of the energy comes out as sound?

Well, drop a very flexible, empty, vessel on the ground, and almost none of the energy from the fall will come out as sound. (Hm, are there any fall-instruments?) But fill the vessel with small bells, and even after lowering the height to compensate the greater weight, I expect you'd get significantly more energy to come out as sound. I see no reason why the same wouldn't hold mm. for other ways to play a vessel.

I guess the reason why empty vessels are expected to make more sound, is that rigid containers will usually sound when empty, but filling content, like liquid or eg. flour, tends to muffle that sound (which probably means you're heating up said content). But this can't be generalised to all modes of sounding a vessel and all possible contents.


The answer to your other question, I guess, would be: No, you probably just slipped on your worst foot and fell forward against a wheel driven grindstone.

Bye
                                                               Mysha

Subject: RE: Do empty vessels make most noise?
From: JohnInKansas
Date: 13 Dec 12 - 12:12 AM

Amos - It's all in that old book by Helmholtz:

On the Sensations of Tone, 2d edition of the Ellis translation, 1885, of Die Lehre von den Tonempsfindungen originally by Hermann Helmholtz, Reprinted by Dover 1954, ISBN 0-486-60753-4.

The biggest difficulty is that one needs to be something of an ARM (Anal Retentive Masochist) to wade through all 576 pages, with a few years of linear circuits and signal transmission theories if you expect to understand all that much, some little of nonlinear servo systems helps, and you need at least a little experience with some variety of musical instruments to appreciate squat of it all. (The last most needed to understand the couple of errors Hermann made due to his minor equipment limitations.)

Recommended reading for any instrument builders/designers, although I wouldn't be so cruel as to say one can't get by without understanding all of it.

Leenia - Changing the volume of air in a container by adding some water changes its pitch, but doesn't directly affect its loudness. You have to start with something that makes a tone in order to tune the tone.

Try stuffing the jug partly full of marshmallows or soapsuds and you'll see the difference. Filling it part way with marbles or BBs will produce something a little different (probably not very pleasing).

John

Subject: RE: Do empty vessels make most noise?
From: Amos
Date: 12 Dec 12 - 08:20 PM

John:

Your clear insightful posts always impress me, but this one was especially gobsmacking. Thanks very much for the education.

A

Subject: RE: Do empty vessels make most noise?
From: Dave the Gnome
Date: 12 Dec 12 - 06:04 PM

Some are filled higher than others, but they all play.

Yea - That is what I was sort of saying before. Even though some vessels have more liquid in they make the same amount of noise. It is just a different one. Likewise with jugs, Roger. Not sure if empty ones are louder or just deeper.

Anyway, it's all academic and I doubt anyone will ever make use of the information. Begs a similar question. If you have your nose to the grindstone, shoulder to the wheel and best foot forward; are you a contortionist?

:D tG

Subject: RE: Do empty vessels make most noise?
From: GUEST,leeneia
Date: 12 Dec 12 - 10:39 AM

http://www.youtube.com/watch?v=ngpx84g1Cfo

That's a video of a man playing music with water glasses. Some are filled higher than others, but they all play.

Warning - the video is loud. turn down your volume for it.

Clearly the answer to "Do empty vessels make the most noise?" is "It depends on the resonant frequency of the vessel."

FYI, I have a wok and its lid which hang on a rack over my stove. When the stove is really going, the lid starts to swing, and when it hits the wok, it produces a low and rather pretty musical note. We like it.

Subject: RE: Do empty vessels make most noise?
From: Roger the Skiffler
Date: 12 Dec 12 - 05:53 AM

Do empty vessels make most noise?...well jugs do.

RtS

Subject: RE: Do empty vessels make most noise?
From: JohnInKansas
Date: 11 Dec 12 - 07:04 PM

pdq -

I thought about following Tony's lead instead of the acoustic comments, but I don't do politics and personalities all that well. And besides that, several of the "empty vessels" suggested there have already been whanged pretty hard without any significant change in the noise.

Take a deep breath, and carry on. ...

John

Subject: RE: Do empty vessels make most noise?
From: pdq
Date: 11 Dec 12 - 06:09 PM

Some posts by JohnInKansas can take all the air out of a room, not just a guitar.

Subject: RE: Do empty vessels make most noise?
From: JohnInKansas
Date: 11 Dec 12 - 04:14 PM

An empty vessel most generally makes no noise at all, just like a filled (or solid) one. How much noise it makes depends on the strength of the abuse applied.

For empty tubes, like flutes and whistles, how hard you blow is the main determinant of how loud they are.

For bars, like xylophones or harmonicas/reed instruments, it's largely a matter of how hard you whack them, or for the reeds, how hard you blow.

For most string instruments, the sound that leaves the instrument and is heard depends on how much movement you can generate in some large surface that can push a lot of air. For things like a guitar, or fiddle, the surface most effective is the top plate of the instrument, but the loudness depends largely on how much the string is stretched when you turn it loose.

The "vessel" volume of the instrument body can have a resonant frequency for the air inside. That frequency is fairly accurately given by the Helmholtz equation that says that the resonant frequency of a partially closed volume is proportional to the total area of all the holes, and inversely proportional to the volume of the air space inside. You can lower the resonant frequency by using a bigger air space, or raise it by using larger (or additional smaller) holes. BUT IT IS NOT THE AIR MOVING IN AND OUT THROUGH THE HOLES that is the most significant source of the sound you hear.

For most string instruments, the top plate, which can also be "tuned" to have one (or more) favored frequencies, is the main thing that pushes the air to produce most of the sounds you hear.

The top plate is connected to the air space, and if the two characteristic frequencies are "close enough" inward motion of the plate can compress the air inside so that the energy of the vibration is stored up in the air to push the top plate back up, to where the plate can move the outside air without losing much of the energy.

This "storage and return" effect can fail if the two frequencies are too far appart, but a small difference in the two frequencies can greatly extend the frequency range over which "about the same" acoustic volume (noise) is transmitted to the external air for any frequency within the frequency bandpass range of the coupled resonant systems. A "weak" instrument may be most likely to happen when the "plate frequency" of the top is too far (or less often too close) to the air volume frequency.

The only thing available to put energy into the "system" is generally the string. The motion of the string that is effective is (ideally) perpendicular to the string, and drives the bridge "up and down." A major source of "lost energy" is any construction detail that allows lengthwise (in the direction of the string) motion of the string across the bridge. Some approaches to bridge design aim at a "slippery bridge" so that the incidental lengthwise motion dissipates very little energy, while others try for a "rocking bridge" that follows this undesired motion with little dissipation. Consensus opinion seems to be that a "stiff bridge" that prevents the motion from occuring at all gives best results. Perfection with any of these methods is exceedingly difficult.

To make the instrument louder, it is necessary that more of the energy stored in the string must be extracted and transferred to the outside air in each cycle. Since there's a limit to how much energy can be put into the string with each pluck (or WHANG) increasing loudness by changing the design features will always reduce sustain, unless some other trick can be used to provide a "bigger whang" such as heavier strings (or stronger picks).

As to the question asked (which I have assumed isn't what you really want to know) any enclosed air volume with a hole in it has a resonant frequency that can be rattled with little loss. You can change the frequency by changing either the air volume, or the sum of the areas of all the holes.

A "smooth" air volume likely will sound better than one that's "fuzzy" on the inside, and the resonance may be "fuzzy" if irregular obstructions are present in the air space. The sound will be "purer" if the container is "fairly rigid" but for common instruments that conflicts a little with the need to transfer vibrations between the inside air and some large part of the outside/exterior surface.

"Squishy things" inside the air volume may upset the resonance since most such things absorb quite a bit of energy, and convert it to "friction heat" that can't be fed back into the sound.

Radical bridge changes may change the frequency of the top plate, by adding a lumped mass that resists going where it should at the same frequency the plate wants, but since all "plate vibrations" are inherently nonlinear the top plate resonance is rather ill defined. It's more likely that unwanted effects for most bridge amendments are due largely to "slippy string" effects unless an unusually heavy bridge amendment is added (or removed).

EVERYTHING about most instruments is a compromise, so concentrating excessively on a single effect, without considering what it does to the rest of the instrument, can produce effects impossible to predict.

"Magic Cures" for an unsatisfactory instrument do not exist - usually.

John

Subject: RE: Do empty vessels make most noise?
From: olddude
Date: 11 Dec 12 - 04:03 PM

Some people's noise is other people's music. Case in point Rap music
sorry I could not resist

Subject: RE: Do empty vessels make most noise?
From: GUEST,Tony
Date: 11 Dec 12 - 03:55 PM

"Empty vessels make the most noise" sounds like a kind of insult, suggesting that people who talk a lot generally have little to contribute; along the same lines as the non-insulting expressions "still waters run deep" and "the squeaky wheel gets the oil."

Subject: RE: Do empty vessels make most noise?
From: Dave the Gnome
Date: 11 Dec 12 - 02:03 PM

Can't remember about the undersaddle pickup Stu (It's actualy a few years ago since we did it but my mind works v-e-r-y slowly :-) )but I think it had one. In which case it was removed!

Good point, Bernard, and I have heard the guitar!

Not sure about the bucket adage, Nigel, although I know what you mean. When you get bottles however they change tone when you add water but do they get any louder or quieter?

Cheers

DtG

Subject: RE: Do empty vessels make most noise?
From: Nigel Parsons
Date: 11 Dec 12 - 04:51 AM

Generally speaking though, the old adage is sound.
Hitting an empty tin bucket (pail) will make more noise than hitting a similar one full of water.

Subject: RE: Do empty vessels make most noise?
From: Nigel Parsons
Date: 11 Dec 12 - 04:48 AM

A truly empty vessel wouldn't make any noise at all -- sound doesn't travel in a vacuum.
If you're in a laboratory, and tap a vessel which has been thouroughly evacuated("a truly empty vessel"), it will make a sound. The sound is being propagated in the air outside the vessel. The vacuum is inside the vessel.

Subject: RE: Do empty vessels make most noise?
From: Rapparee
Date: 10 Dec 12 - 08:27 PM

A truly empty vessel wouldn't make any noise at all -- sound doesn't travel in a vacuum.

Subject: RE: Do empty vessels make most noise?
From: pdq
Date: 10 Dec 12 - 08:02 PM

One point to make.

You don't have an empty vessel or guitar: they filled with air.

The air and all parts of the guitar have resonances.

That is, multiple resonances and all at different frequencies.

Clamping a pickup to something that is intended to resonate will damp that resonance.

Preventing the free movement of air will also damp resonances.

Subject: RE: Do empty vessels make most noise?
From: Commander Crabbe
Date: 10 Dec 12 - 07:53 PM

When I bought my mandolin there were two of the same design to choose from. One with fitted electrics and one without. After much tooing and froing between the instruments with a flat pick I chose the one without electrics as it sounded brighter than the other.

That said when I bought my Suzuki 3S guitar there were two of the same model both without electrics which looked identical. However one had a slightly better sound than the other.

In both cases each instrument had good tonal qualities but one just sounded better than the other.

So maybe the electrics had nowt to do with it after all.

Chris

Subject: RE: Do empty vessels make most noise?
From: Jack Campin
Date: 10 Dec 12 - 07:26 PM

I was once given a Romanian D whistle turned out of one piece of wood (produced in the Hora factory in Reghin, though they don't list whistles as a product line and as far as I can tell never have done). The bore had not been cleaned up at all - very rough, with splinters where the holes had been drilled. And nearly a semitone flat. I sanded out the inside of the bore, oiled it, sanded some more, polished it with a length of threaded rod, oiled it again, polished it with a length of dowel, oiled it again. Nice bright tone and dead on pitch.

Subject: RE: Do empty vessels make most noise?
From: Bernard
Date: 10 Dec 12 - 06:39 PM

I have a cheap Yamaha guitar (one that I take places and don't mind people borrowing - our own Dick Greenhaus once used it at Swinton, DtG's club).

I decided it probably wouldn't do much harm to it if I installed an undersaddle pickup... it just so happened that the amount of plastic I would have had to plane off the bottom of the saddle was exactly the same thickness as the wood in the bottom of the bridge slot.

So I bit the bullet and removed the wood instead, so the pickup now sits directly on the belly of the guitar with the saddle on top.

Amazingly, the volume practically doubled and the tone improved quite remarkably. Okay, it's still not a prized instrument, but far better than when it came out of the factory.

Sorry, Dave, off topic...!! ;o)

Subject: RE: Do empty vessels make most noise?
From: s&r
Date: 10 Dec 12 - 06:14 PM

Just out of interest Dave did you temove the undersaddle pickup?

Stu

Subject: Do empty vessels make most noise?
From: Dave the Gnome
Date: 10 Dec 12 - 06:02 PM

I can think of a few on here who would prove the concept :-) But seriously, and musically, is there a relationship between the emptiness of the vessel or instrument and either the volume or quality of sound it produces?

We had a Marlin acoustic guitar - Not expensive and certainly not what you would call a loud instrument. It did contain some electronics however which, in latter years, failed. So we took them out. Now we have a guitar with no internal gizmos; two extra holes in the side where the knobs were and a sound so improved it could be a different instrument!

Anyone else experienced this? Or the converse where something has been added that has either spoiled or deadened the sound? Purely out of academic interest. Although, knowing Mudcat, it could turn into a full scale war... :-)

Cheers

Dave the Gnome