Does the position of the bell brace have an effect on accoustics / resonance of the tone

[hakukani]

I'm not sure what is meant by 'resonance' in the sense that you're using it here.

Also, if you bend the bell back more toward the rest of the horn, aren't you modifying, slightly, the geometry of the horn?

[Henry D]

Clearly, moving the bell would have an effect upon the geometry- though even a pretty severe movement of say a quarter inch at the point of the bell brace contact would probably not prove acoustically detectible, especially in a baritone.

I took Mr. Roseen's comments to address the <perceived> vibration in the bell, not the sound coming out of the horn though.

There would surely be a difference in that aspect as a result of relieving the effective preload induced by a stressed bell stay attachment. I believe Drake Sax Prof's observations would seem to support this notion.

[Graysax]

I'm not sure what is meant by 'resonance' in the sense that you're using it here.

Also, if you bend the bell back more toward the rest of the horn, aren't you modifying, slightly, the geometry of the horn?

Resonance the way I am using it is the intensity of vibrations caused by the sound in the air column. I also find that the greater the vibrations, the bigger the sound - again just an OPINION.

As far as bending the bell back towards the rest of the horn - the bottom bow is where this bending is occurring, and it is a situation where a small bend has a great distance because the noted problem is much further away. I.E. - a 0.25 degree angle at the source does not have much distance in the ray (is that the right term? - pulling from jr high math classes here) - however a couple feet away the distance of the ray (again excuse me if I am using the wrong term) could be a half inch or so.

That is enough to cause the amount of tension in the brace (if not fixed properly) that can cause the problem I am talking about.

Also - think of the repair as putting the bell back to where is was meant to be as opposed to changing the inner bore dimension.

[Henry D]

A one degree movement at the bow of a baritone would cause "about" a 1/6th inch movement at the stay point.

This assumes 18 inches as the height of the stay point.

[Buck Laughlin]

The metal does not vibrate. This is a proven acoustical fact.

Huh?

[patrik roseen]

...
If you read Graysax carefully you realize that the real issue was bending the bell back so that the brace was a perfect fit before soldering. It's situations where one has to flex the pieces into position and then have the brace hold them there that result in tension.

That issue can occur wherever the brace is designed to be on the bell unless the assembly is properly done.

Was it? Unsolder the brace and if it sproings free it wasn't. It's, of course, a lot easier to check on a horn with a screw on brace. Unscrew it and there should be no movement...

I can buy into this.
Maybe this is what triggered my question in the first place.

One reason for a bellbrace coming off is usually that the horn has been knocked and the place where the bellbrace used to attach on the upper stack has become indented. This dent is not easily removed hence the tension required when bringing the parts together.

It just does not seem optimal to resolder something this way. Practically leaving the horn with this tension. Which has been confirmed by Graysax.

[alljoe]

Now that interesting resonance change but maybe not perceived tone. the papers that do the math show the material stiffness of the walls being so much stiffer than the air that materials and finish don't matter. if the walls are moving due to the resonance that would seem to look like a geometry change to the air volume. wouldn't that have a significant effect on the tone?

Ok - now I am going out on a limb and give some OPINIONS based upon my experiences, both as a player and as a repair tech.

The theory of the air column is fact. No arguments there, however it is my OPINION that once the column of air resonates, it transfers the resonance to the metal body tube (and bell, and neck). The resonating tube, then re-affects the column of air in the tube and changes the character of the sound. (NOTICE I DID NOT SAY "TONE")

I can give one clear example (in addition the the many subtle ones that would take to long to explain here).

Years ago, my 1969 Buffet SuperDynaction Low A Baritone was my main horn while studying at SUNY Fredonia. The bell to body brace is the same design (and size) for the Alto, Tenor, and Baritone. This resulted in a brace that is too small for the large bell of this Low A saxophone, and thus it broke.

I had it soft soldered when I was in college. It broke again. Well, after a few times of it breaking again over the next few years, I had enough, and as I was apprenticing at a repair shop, I decided to fix it right. I took off all the parts of the brace, silver soldered them all together, then put them back on the horn as a one piece brace.

Now, here is where it gets interesting. Over time, the weight of the bell bent it slightly forward, so in order for the brace to be attached needed to be bent against the natural spring of the situation at hand. This is how it had been since the last repair, which means the brass of the saxophone had constant strain at that point.

When fixing this problem now the correct way, I straightened the bell so the brace fit between the bell and body with very LITTLE pressure holding it in place - thus no strain or pressure on the brass.

When the "fix" was finished and the horn was re-assembled - the resulting resonance was astounding. Again, not change in sound, but change in resonance. The old brace attached under tension, hampered the transfer of free resonance in the body tube from the air column.

I will also add that later in life I had this horn silverplated. Again, sound did not change, resonance did however.

It is MY OPINION that things that impact the secondary resonance of the body (primary being the air column) , are perceived by the player as a change in sound - but in reality are a change in resonance.

OK people, I am ready for you to hang me at the old oak tree for these opinions now. I will bring my own rope and black hood.

Charlie

[Henry D]

Now that interesting resonance change but maybe not perceived tone. the papers that do the math show the material stiffness of the walls being so much stiffer than the air that materials and finish don't matter. if the walls are moving due to the resonance that would seem to look like a geometry change to the air volume. wouldn't that have a significant effect on the tone?

Sure they move- no one ever seriously disputed that. But how much? The bore of the sax is so huge compared to any dimensional change involved as to make it a non effect acoustically for any practical purpose.

Doesn't mean you can't feel it. Doesn't mean it won't affect a player's perception of feedback and so how that player works the horn.

Just means that to someone not playing the horn any difference is below the noise level.

[Gordon (NZ)]

AFAIK the vibration modes of the bodies of wind instruments has been studied quantitatively, including the way that vibration couples with the vibration of the air column. Not to mention the amplitude of vibration measured. And the conclusion is that for woodwinds, the vibration of the body of the instrument sends out sound waves to the listeners ear that are sufficiently minute in volume that although they can be measured by test equipment, they are not discernible to the human ear. And double blind testing confirms this.

By comparison, the sound produced by the vibration of a bell of a brass instrument, particularly French horn, begins to be discernible, and of course the bell is involved for every note, which is definitely not the case for woodwinds.

However some woodwind bodies vibrate a little more than others, and I am sure that when I experience that, my easily deceived senses and brain interpret that tactile pleasure as improved sound. The audience, of course, would not experience that.

[Graysax]

And the conclusion is that for woodwinds, the vibration of the body of the instrument sends out sound waves to the listeners ear that are sufficiently minute in volume that although they can be measured by test equipment, they are not discernible to the human ear. And double blind testing confirms this.

We are all talking about our perception vs listener perception (or mechanical measurement)

My question is to the player's perception. How often do we see a guy play something and say - "do you hear that?" when in truth we the listener, heard nothing.

I was taught that the way we hear ourselves is based upon the fact that sound travels faster through solids than air. Your jaw bone is the link between your mouthpiece and your eardrum.

So "we the player" will notice things that "they, the listener" could care less about. We then try to impose what we experience onto the listener, they just think we are crazy and obsessive.

In truth, we are! :-)

Anything not humanly connected with the saxophone during performance, in my opinion, lacks the technology to perceive the sound as the performer does. Very similarly as a photo will never be EXACTLY as good as the real image.

The REAL talented guys are the ones "in touch" with this aspect at some level, and can convey, or bring notice to their own perceptions.

[Graysax]

A one degree movement at the bow of a baritone would cause "about" a 1/6th inch movement at the stay point.

This assumes 18 inches as the height of the stay point.

Alright - I lacked the knowledge of the formula - however my point stands.

[Henry D]

No, no. Sorry if I came across as snarky; I agreed with your point that a very small change in angle at the bow could effect quite a movement by the stay.

[hakukani]

No, no. Sorry if I came across as snarky; I agreed with your point that a very small change in angle at the bow could effect quite a movement by the stay.

It's certainly more of a change than removing the lacquer

[Henry D]

Think so?

I believe neither would be audible.

The change in volume or bow cross section caused by a one (or two) degree bend would be very, very, small- less than the change effected by sticking a one inch square piece of tape on the interior surface. Even that small effect would largely be erased when the bell was flexed to come up against the stay.

The removal of lacquer- and I'm in the "no audible effect" from finish camp- might have some minute effect on the feel of vibration transmitted to the fingertips on some notes.

So might the relief of tension from the bell.

I'm speculating that between the two you'd get more effect at the fingertip sensation level from the tension relief than from the delaquering, and that neither would be detectible to any listener. Might be felt to be different in a double blind- but surely not with anything approaching a 100% positive ID even for experienced players.

Absent a study- and I sure have none to cite- I figure "speculation" is about all we have.

[Dr G]

Absent a study- and I sure have none to cite- I figure "speculation" is about all we have.

Speculate on then. At least one horn tech that I consider credible, Randy Jones, makes it part of a rebuild to remove the tension from the bell brace (remove the brace, reset the bow, reattach the brace in the tension-free position).

[kymarto]

A few quick comments. The material and design does very definitely affect the sound of an electric guitar. When a string vibrates, energy is lost at the nut and bridge, which are displacement nodes of the string. The mechanical energy of the string is transferred to the body, and how that happens affects the behavior of the string. In fact this is exactly why an electric guitar has such great sustain as compared to an acoustic guitar; in the former, there is no need to transfer energy in order to create sound, whereas in the latter if you don't transfer energy, you can't drive the acoustic resonator.

There is evidence that the only part of a wind instrument in which vibrations might actually have a significant acoustic effect is in an unsupported bell, since it is the only part of the horn that has resonant frequencies low enough to couple at playing frequencies. So yes, the position of the bell brace could make an audible difference, albeit a small one, maximum about 3 dB according to Nederveen.

[patrik roseen]

Interesting!
Yes you are right, the sustain of the electric guitar is well designed for wheras for an accoustic guitar or violon for that matter the energy of the string is supposed to move from the string, to the bridge and over to the bottom and top of the soundbox. A violin has a wooden pillar inbetween the top and bottom just in front of the bridge to get the vibration to the bottom.

So a non braced bell is 3dB stronger than braced one. 3dB means twice the power. This is not negligable, is it?

[hakukani]

1db SPL (sound pressure level) is a ratio that is supposed to be the 'minimal detectable difference' in level. You have to listen quite hard to tell a 1 dB difference between two sounds.

3 dB is 'just noticeable difference', so no, 3 dB isn't that much difference in SPL.

You are correct when you say that 3 dB is double the power (watts). It takes double the power in an amplifier to create a just noticeable difference of 3 dB.

[kymarto]

3 dB is the maximum postulated difference at certain frequencies. It is most probably much less, based on the fact that a sax has very little bell flare and only on the lowest notes does anything near the full power of the air column vibration reach the bell.

Smith did tests with trombone bells of different thickness and measured a variance of 2dB at certain frequencies at the position of the player's ear. Interesting not one of ten top pro bone players could distinguish between the bells in blind tests.

[Graysax]

Smith did tests with trombone bells of different thickness and measured a variance of 2dB at certain frequencies at the position of the player's ear. Interesting not one of ten top pro bone players could distinguish between the bells in blind tests.

My question is measuring dB at the outside of the player's ear relevant, because the sound is traveling through the jawbone to a location VERY near the eardrum? If sounds travels faster through solids than gas, is measuring dB outside the body vs through the inside of the body like comparing apples and oranges?