What physically is "projection"?

[sirisobhakya]

Sorry if this question is irrelevant. My engineering curiosity is at it again.

As far as I understand, projection is the quality regarding how well the horn can be heard at a distance. Good projection means the horn can be heard well far away, or standing out from the rest of the playing group. Please correct me if I an wrong.

But if the meaning is in that ballpark, what makes a horn system (meaning: horn and mouthpiece) projects? Is it the lower harmonics that lose less energy and thus can be heard farther than higher harmonics?

Since a horn with heavy parts is said to project better that that with light parts, this explanation should make sense (heavy horn seems to attenuate higher harmonics and/or reinforce lower harmonics, thus making projection better). Or it is just the feedback is less than lighter horn and so the player tries to play louder, thus can be heard better over the distance? Or is there any other explanation?

[Kbiggs]

This may not be helpful. It’s mostly personal experience and understanding about what allows projection. I don’t know whether it’s based on physics or acoustics…

What I’ve been told is that, all things being equal, higher frequencies move faster and are heard before lower frequencies. If you listen to a band, you tend to hear the piccolos, flutes, clarinets, cymbals and snare milliseconds before you hear the tubas and bass drums. In an orchestra, you’ll hear the violins milliseconds before the basses and cellos.

For a trombonist, if you use a heavier gauge horn (thicker metal) and larger venturi (mouthpiece and leadpipe), you produce more lower frequencies in the sound. Additionally, it takes more effort to get the lips to vibrate and excite the standing air column. More effort=more air=more frequent and larger breaths (compared to thinner gauge and smaller venturi of the same length and tube diameter). Conversely, thinner gauge and smaller venturi will emphasize upper frequencies.

Personally, I’ve moved towards lighter and smaller equipment over the years (I’m only getting older), and I believe it allows me to project more easily with less effort/physical exertion. I used to play a 42B with a Thayer valve, heavy weight bell, short open leadpipe, and a Monette mouthpiece. I now play a 42B with an Instrument Innovations rotor, a regular weight bell, a modified standard leadpipe (either a stock that has been cut down by 1/4” or an MK standard), and either a GB or a DE mouthpiece. Similar equipment changes with my 50B. I used to sound like a bulldozer. I believe I am sounding more like a trombone.

I don’t remember who said this (perhaps Doc Severinsen?), but they described the upper frequencies as “the rub” in the sound, the quality that allows the sound to project, while the lower frequencies were “the power and color” in the sound.

[harrisonreed]

I do not know exactly why or what the physics are for getting a horn to project, but I do not think it has to do with working harder, or the horn tricking you into working harder. There is some equipment that just puts out more sound for the same input than other equipment does. Here are my observations in my quest to get more projection. Tried all of these:

1. Horns with sterling silver bells project better than brass.
2. Yellow brass bells project better than red or rose brass.
3. There are some tuning slides that seem to get the horn to slot better, and these also seem to project better.
4. A heavy mouthpiece seems to project better than a light one.
5. Mouthpieces with larger throat diameters project more.
6. Mouthpieces with backbores that are too open (for the rest of the mouthpiece) do not project as well.
7. Wrapping the throat of the bell near the main brace with dampening material such as tape or leather increases projection.
8. Adding weight to the bell in conjunction with #7 increases projection.
9. Cut bells with heavy throat collars seem to project better.
10. Sterling leadpipes seem to project better.
11. Decreasing how far the mouthpiece goes into the leadpipe, ie with tape, OR increasing the overall length of the mouthpiece (by extending the shank length in the design) seems to increase projection.

[ithinknot]

I do not know exactly why or what the physics are for getting a horn to project, but I do not think it has to do with working harder, or the horn tricking you into working harder. There is some equipment that just puts out more sound for the same input than other equipment does. Here are my observations in my quest to get more projection. Tried all of these:

For science, maybe it's worth considering which of these primarily reduce feedback to the player (whether through mass or, in the case of #11, by moving the bell further from your ears). The ratio of direct bell spill to reflected room sound changes, and "more room" will likely read to the player as "better projection" whether or not the sound in the cheap seats is different... a la Harmonic Bridge.

Not actually disagreeing, though... for example, it's ridiculous how much louder and projectionsome a 3BSS can be from either side of the bell, compared to a 3B given the same subjective level of input effort. (In that case, I suspect it has more to do with the thing's sheer chonk than the material-specific overtone profile... it would be interesting to test a sterling bell with sheet thicknesses chosen to give the same final mass as the yellow/rose, but that's not something that exists for your 3B/88H.)

[AndrewMeronek]

Clarification: perceived volume of the same instrument on different frequencies, or different instruments on the same frequency?

[Trombonic]

Some of my students project very bad untill I tell them to "think" higher ( "tee" tongue instead of "ta" or even "too"). The sounds get more brightly and it projects way better. So it is not just the equipment I guess.

[chromebone]

Projection is clarity. A clear sound will be heard better farther away than a dull sound. It’s that simple. One of the biggest turning points for me as a player I had was taking a lesson with Jay Friedman. He spent the entire 1 1/2 hours of the lesson talking about a clear sound and how to achieve it. After the lesson, he told me to go to the CSO matinee concert and hear them play Tchaikovsky 6. There probably isn’t a better piece in the repertoire to hear everything the trombone does in an orchestra, from ppp to fff.
What I heard was a revelation: The section has a reputation for playing “loud”. They never played that loud, even in the loudest sections (Tchaikovsky fffff). What they did do was play clear. There’s many reasons Friedman is still playing at the top of his game in his mid-eighties, but one of them is certainly that he is not working too hard to get a sound that can be heard clearly, without having to force the sound. His concept of stressing clarity over strength is why he can be heard all the way to the back row in the upper balcony even after 60 years of playing.

[imsevimse]

As others have said: projection (when positive) is about having a good blend of sound, but especially to have the higher frequencies present and working for you.

Some horns apparently help better with this. For me "good projection" is not something I can hear behind the bell, it is something that others on the other side of the room pick up. When I've heard that said about my playing I have not been aware of it at the time. The conclusion I draw is it has to do with the horns AND the player since the comments are not random. It could be right combination of player/horn/mouthpiece is what gives the projection.

I've noticed I get theese comments only when I'm on bass and only on certain horns and with certain mouthpieces, and the listner then doesn't know what gear I use. The other thing I've observed is it doesn't happen when I play
10" basses, only if I play a 9" or 9.5". The Kanstul 1662 apparantly is a horn that projects very well. When I play that horn I hear that a lot and apparently all the singles I use seem to project well too, it's what people say. I've never heard it said when I'm on tenor. I wonder if that is a good thing or a bad thing.

/Tom

[tbdana]

Projection is clarity. A clear sound will be heard better farther away than a dull sound. It’s that simple.

This feels right to me. But then it just begs the question what is clarity? What is a "clear" sound?

[sirisobhakya]

Thank you for all the insights and observations. They are highly appreciated

However, for me they opened up more questions:

1. If projection comes from higher frequency, the reason which is in-line with the effect of bell diameter (larger = less higher overtones and more lower overtones due to reduction of shockwave and higher frequency waves due to non-linearity -> less projection) and damping the bell (arguably preventing bell vibration which absorbs energy and thus attenuate higher frequencies), why larger throat diameter of the mouthpiece and heavier bell, both supposed to "darken" the sound (= less higher overtones) make projection better? Is the result of less feedback to the player and thus the player has to play louder to get the same feedback plays a part in this?

2. Higher frequencies has higher energy than lower frequencies, but it should be easier to be attenuated, for example FM and AM, or blue light scatters easier than red light. So isn't the frequencies that can be heard over a distance the lower one? Or is the scale of normal concert hall or stadium still not relevant (still too small for attenuation to be noticeable)?

And on parallel issue:

It is believed that a smaller bell makes the sound more directional. However from a research found here suggest that a larger bell is more directional (maybe to a point?). What is your opinion/experience on this issue?

The reason I ask these questions is that I am writing an article on how the size of the bell affects the sound on my Facebook page. I would like to know why it is so physically, what the shape of the bell does to airstream/sound wave for example.

[sirisobhakya]

Projection is clarity. A clear sound will be heard better farther away than a dull sound. It’s that simple.

This feels right to me. But then it just begs the question what is clarity? What is a "clear" sound?

I think the easiest way to explain this, in my understanding, is that a clear sound is achieved when the lips vibrate freely, thus most possible frequency bands are present. If one pucker one's mouth too much, or blow with too much tension, the lips cannot vibrate as freely, and some of the frequency bands (especially higher ones) will be missing.

[imsevimse]

This feels right to me. But then it just begs the question what is clarity? What is a "clear" sound?

I think the easiest way to explain this, in my understanding, is that a clear sound is achieved when the lips vibrate freely, thus most possible frequency bands are present. If one pucker one's mouth too much, or blow with too much tension, the lips cannot vibrate as freely, and some of the frequency bands (especially higher ones) will be missing.

Yes, and what sometimes is neglected that the slide must be at the EXACT spot. If you are off by a couple of mm it matters. Another thing that also need to match is the mouth cavaty and also the well supported aircolumn from lungs. No unnecessary tensions allowed in your body that decrease vibrations and resonanse. When you get this right you get a full complex sound that may project well in the positive sense. I'm suddenly thinking of a trumpet player I know who can be heard through any orchestra but I don't think anyone would describe his sound as a sound that projects well. I think people rather would describe his playing as "We can hear him".

/Tom

[dwcarder]

If you have a basic physics background, this is a great resource pointing out some of the factors involved with what's going on: https://www.phys.unsw.edu.au/jw/brassacoustics.html
And of course there's even more effects at play such as metallurgy, wall thickness, dampening effects, etc. It's remarkably a very complex physical system to reason about, not even considering the variability of a human player.

[Doug Elliott]

More than just "higher frequencies" I think it's more specifically WHICH harmonics are strong, what proportion, and intonation of the harmonics. Harmonics are not necessarily automatically in tune, and any part of the sound that is out of tune has the potential of cancelling other parts. It's a combination of embouchure/mouth cavity mechanics and mouthpiece/horn factors. A great mouthpiece and horn can still be played badly and not project, and marginal equipment can be played well and project if the player knows how.

[chromebone]

Projection is clarity. A clear sound will be heard better farther away than a dull sound. It’s that simple.

This feels right to me. But then it just begs the question what is clarity? What is a "clear" sound?

I’d say, from what Friedman was explaining, it was more emphasis on higher frequencies. He talked about directing the airstream in a way that emphasized higher frequencies. That, coupled with an unforced breath release into the horn: aim towards the somewhat higher side of the partial, take as big a breath as possible, release, and let the lungs empty with as little muscular force from the diaphragm as possible. Pretty simple but effective.

[brassmedic]

More than just "higher frequencies" I think it's more specifically WHICH harmonics are strong, what proportion, and intonation of the harmonics. Harmonics are not necessarily automatically in tune, and any part of the sound that is out of tune has the potential of cancelling other parts. It's a combination of embouchure/mouth cavity mechanics and mouthpiece/horn factors. A great mouthpiece and horn can still be played badly and not project, and marginal equipment can be played well and project if the player knows how.

Harmonics are mathematical divisions of the sound wave. How could they be out of tune? I'm not talking about the different notes you can play in the overtone series, which can differ in intonation, but rather the harmonics that are part of the sound we are hearing. It's defined as a component frequency of a complex wave that is an integral multiple of the fundamental frequency. My understanding has always been that timbre is determined by the relative strength or weakness of the harmonics, not by their intonation. Maybe one of the engineers here can weigh in on this?

[Doug Elliott]

Consider the voice, which has "harmonic" overtones that aren't even mathematically related at all.

[ithinknot]

Harmonics are mathematical divisions of the sound wave. How could they be out of tune?

https://en.wikipedia.org/wiki/Inharmonicity

[ithinknot]

aim towards the somewhat higher side of the partial

This idea involves quite a lot of complex factors but, for the purposes of the current discussion, it's worth remembering that within a certain band of acceptability (and applied consistently, and depending on context) slight tuning differences can tend to read as "tone color" rather than "intonation". Sharp is sharp, but very slightly sharp can be "bright but in tune".

[Doug Elliott]

Inharmicity is why piano tuning is a very complex art... Strings are tuned partly to fundamentals but sometimes to harmonics to make intervals sound better. "Equal temperament" is not always equal on different pianos, or as heard by different ears.

[imsevimse]

Consider the voice, which has "harmonics" that aren't even mathematically related at all.

Great idea. The voice is better as an exampke of projection. What is it that opera singers do that make them cut through an opera orchestra without having a microphone? They know how to make resonance. They get that very strong formant that carries their voice to the other side of the room and they look completely relaxed. I've often sung in choires with soloists with big voices and wondered how they acheieve. One thing I've noticed is it is NOT at all about force/power/muscles. They use far less air than I do but still in one breath can last far longer phrases and carry through the room. They obviously know what projects. Compare this to a pop singer who need a mic for anything and often use every muscle in the face. Despite the hard vork their voice can be like a whisper and have absolutely no projection without the mic. Volume and effects like echo and reverb need to be added to make such a voice project. The opera singer is the one we should study.

/Tom

[afugate]

Interesting discussion.

[snip] What is it that opera singers do that make them cut through an opera orchestra without having a microphone? They know how to make resonance. They get that very strong formant that carries their voice to the other side of the room and they look completely relaxed. [snip]

Here's a Scientific American article about opera singers and projection.

--Andy in OKC

[timothy42b]

Harmonics are mathematical divisions of the sound wave. How could they be out of tune?

https://en.wikipedia.org/wiki/Inharmonicity

Good article. The partials of a trombone have a good deal of inharmonicity and that amount varies from horn to horn.

But the article goes on to point out that a driven response is different:

When a string is bowed or tone in a wind instrument initiated by vibrating reed or lips, a phenomenon called mode-locking counteracts the natural inharmonicity of the string or air column and causes the overtones to lock precisely onto integer multiples of the fundamental pitch, even though these are slightly different from the natural resonance points of the instrument. For this reason, a single tone played by a bowed string instrument, brass instrument, or reed instrument does not necessarily exhibit inharmonicity

.

[Olofson]

The sound from a trombone can be more or less pure. There are always sounds in the sound that does not belong to the overtoneseries. Like a voice, it can be hoarse or very clear. A hoarse voice does not project, the clear voice does.

[harrisonreed]

Just one more observation regarding projection:

On brass that is projecting to the back of a hall, especially if the hall is empty during rehearsals for example, you can hear early reflections bouncing off the wall. It's almost like a double articulation or double slap on hard articulations.

I have an example of this on a recording of one of the rehearsals of a concerto I played, in the empty concert venue. I'll try to post it if I get a chance.

[ithinknot]

mode-locking

Yes, and/but that's one of many complex interactions. Brass acoustics are crazy. http://www.phys.unsw.edu.au/music/peopl ... r2000c.pdf gives an easy reading overview of nonlinear phenomena, including the shock wave formation involved in a trombone's shift towards tonal brightness at higher dynamic levels.

On brass that is projecting to the back of a hall, especially if the hall is empty during rehearsals for example, you can hear early reflections bouncing off the wall. It's almost like a double articulation or double slap on hard articulations.

Absolutely, though the player's personal assessment of this is relative to the amount of direct sound and/or more proximate reflections they're getting.

[harrisonreed]

Absolutely, though the player's personal assessment of this is relative to the amount of direct sound and/or more proximate reflections they're getting.

I'm talking about a recording made from the back of the hall objectively, not my personal assessment of what I was sounding like.

[brassmedic]

Harmonics are mathematical divisions of the sound wave. How could they be out of tune?

https://en.wikipedia.org/wiki/Inharmonicity

Hmmm... that article states that brass instruments are "perfectly harmonic":

List of instruments

Perfectly harmonic

Bowed string instruments[8] (violin, cello, erhu, ...)
Brass instruments (trumpet, horn, trombone, ...)
Reed aerophones (oboe, clarinet, ...)

[ithinknot]

I'm talking about a recording made from the back of the hall objectively, not my personal assessment of what I was sounding like.

I know, I'm just making the point that you'd need a recording or third party to judge (especially when the equipment questions become part of the discussion)

https://en.wikipedia.org/wiki/Inharmonicity

Hmmm... that article states that brass instruments are "perfectly harmonic":

Well, with conventional playing techniques i.e. not stuff like lip multiphonics (and certainly by means of comparison to the wholly different categories of instruments that follow, such as untuned percussion) that's functionally true. But your original question seemed to suggest that you were unfamiliar with the concept of inharmonicity in any context relating to timbre. The Fletcher article above explains how fundamentally inharmonic strings or tubes can generate repeating (i.e. harmonic) waveforms.

[harrisonreed]

FWIW, here is what I mean about the early reflections. Not sure how it might be helpful, but it is an observation. I was projecting here, at least I think I was. You can hear the sound bouncing off the walls before the main sound gets to the mics. The mics were all the way in the back of the hall.

[ithinknot]

FWIW, here is what I mean about the early reflections. Not sure how it might be helpful, but it is an observation. I was projecting here, at least I think I was. You can hear the sound bouncing off the walls before the main sound gets to the mics. The mics were all the way in the back of the hall.

You sound great, but move the mics forward

[harrisonreed]

It was just a zoom and they wanted to know the sound in the cheap seats when they used it.

[brassmedic]

Well, with conventional playing techniques i.e. not stuff like lip multiphonics (and certainly by means of comparison to the wholly different categories of instruments that follow, such as untuned percussion) that's functionally true. But your original question seemed to suggest that you were unfamiliar with the concept of inharmonicity in any context relating to timbre. The Fletcher article above explains how fundamentally inharmonic strings or tubes can generate repeating (i.e. harmonic) waveforms.

I was not familiar with the term inharmonicity at all. Thank you for bringing it up. I'm just trying to understand this, in the context of trombone playing and Doug referring to "intonation of the harmonics". The Wikipedia article seems to suggest that trombone harmonics are always perfectly in tune (assuming, as you mentioned, that the player is actually producing musical pitches on it). But maybe I am not understanding what it's saying. It also seems to be saying that the concept of inharmonicity applies chiefly to unpitched instruments like percussion.

To say a harmonic is "out of tune" would mean to me, in a hypothetical example, that if you played A=440, the second harmonic would occur at some frequency other than 880, and that 880 hz would be missing from the sound spectrum. And the article is saying that doesn't happen. But again, perhaps I am misunderstanding what's being said.

[Doug Elliott]

A friend is a piano tuner (and trumpet player) and has an app that can read the intonation of every harmonic individually, regarding piano tuning. We've had discussions about this before but I'll have to ask him if it can do the same for brass sound.

But I'm at ITF now and won't be home for a while.

You know how some players have sound that is impossible to tune to? I don't think it would be that way if all the harmonics lined up perfectly.

[brassmedic]

A friend is a piano tuner (and trumpet player) and has an app that can read the intonation of every harmonic individually, regarding piano tuning. We've had discussions about this before but I'll have to ask him if it can do the same for brass sound.

But I'm at ITF now and won't be home for a while.

You know how some players have sound that is impossible to tune to? I don't think it would be that way if all the harmonics lined up perfectly.

Cool, thanks. I find this stuff really interesting. Enjoy ITF.

[imsevimse]

Interesting discussion.

[snip] What is it that opera singers do that make them cut through an opera orchestra without having a microphone? They know how to make resonance. They get that very strong formant that carries their voice to the other side of the room and they look completely relaxed. [snip]

Here's a Scientific American article about opera singers and projection.

--Andy in OKC

Thank's! Very interesting article. As I understood this the male opera singer especially, has to reinforce a higher frequency in his voice to cut through, and his vibrato uses also help the listener isolate his voice from the instruments voices. The accompanying instrumentalists do not use the same prominent vibrato a singer use.

/Tom

[ithinknot]

I was not familiar with the term inharmonicity at all. Thank you for bringing it up. I'm just trying to understand this, in the context of trombone playing and Doug referring to "intonation of the harmonics". The Wikipedia article seems to suggest that trombone harmonics are always perfectly in tune (assuming, as you mentioned, that the player is actually producing musical pitches on it). But maybe I am not understanding what it's saying. It also seems to be saying that the concept of inharmonicity applies chiefly to unpitched instruments like percussion.

Inharmonicity is those unpitched instruments' "whole thing"... but inharmonicity applies everywhere that isn't an idealised mathematical model. Sometimes the model is "close enough", and sometimes the modes of the string or tube itself are inharmonic, but the musical sound generated is harmonic/repeating because of the non-linear nature of the sound generating mechanism.

The more you care, the more complex it gets. Parts are supposed to fit precisely, right? That's what Wikipedia would say. But one probably expands more than the other when heated, and if the fit is too tight you don't get enough solder penetration, and so it goes.

Here's what I think is going on - basically a long walk through Doug's suggestion - but I'm not a physicist, so...

A violin string has inharmonic modes, calculable from its radius, elastic modulus, and tension. When you pluck it, you get a non-repeating waveform. Under normal bowing, you get a repeating waveform. The basic system has inherently inharmonic properties, but the inharmonicity of the musical sound depends on the chosen generating mechanism. It's not an either/or, though... at the extremes of bowing, the slip-stick mechanism and its resulting mode-locking no longer work perfectly, and non-repeating (inharmonic) waveforms reappear. This might be beginner playing, or deliberate "scratch tone" heavy pressure bowing, but either way inharmonicity results.

On the trombone, we agree that there can be harmonic (mode-locked, and conventionally "nice") sounds, as well as non-harmonic results (deliberate non-sung multiphonics, non-deliberate whatevers), all arising from the same basic sound generating mechanism (lip vibrations). Within the mode-locked sounds, there's still a wide range of possible tone color; changing the formant (vowel shape, etc) alters the weighting of harmonics without affecting their frequency alignment. But between repeating and non-repeating waveforms, in practice there's clearly a spectrum:

- officially controlled lip multiphonic; the composer will be delighted
- hint of double buzz but basically one note
- better than last week, I'll give you that
- the perfect sound, an old man weeps silently, #iplayshires

We can model the extremes, but it's not so simple in the middle... and, in reality, most things are at least slightly in the middle. I'll ask Murray Campbell the next time I see him.

You know how some players have sound that is impossible to tune to? I don't think it would be that way if all the harmonics lined up perfectly.

All that said, missing or oddly weighted in-tune harmonics can do this to some degree... the sine wave drone is pretty useless, square and triangle (odd harmonics only) aren't much fun, sawtooth (all harmonics) is better, nicely weighted synth cello better still. But I bet it's both (and probably some other factors besides) and, given that those people's sound can still seem relatively "normal" as a pure question of timbre until you start trying to interact with it, inharmonicity seems like a good explanation.

[AndrewMeronek]

A clarification, because the following confusion is common: harmonicity, inharmonicity and the analysis of overtones that sound above a fundamental pitch are a different phenomenon from partials that we use to lip-slur. Partials also have very little to do with projection.

For things that affect projection, there is also the acoustics of a performance space. I'm sure that many of us have noticed playing in some rooms where the low trombone register just gets sucked into a muffled mess, and in other rooms the low register "pops" and blending feels effortless.

I think there is simply too much covering the generic term "projection" and that it's more useful to narrow down the focus to specific circumstances.

[JohnL]

I'm sure that many of us have noticed playing in some rooms where the low trombone register just gets sucked into a muffled mess, and in other rooms the low register "pops" and blending feels effortless.

I've played in venues where the section sounded balanced on stage and the conductor was actually asking for more trombone, yet I was hearing my sound coming back at me from the back wall.

[tbdana]

Reading this thread I'm reminded of a story Jeff Reynolds told me about a month ago.

He talked about being on a recording session with George Roberts back in the day, sitting next to him with the two of them sharing a mic. Jeff would go into the booth to listen to playbacks, and he could hear George coming through clearly, but couldn't hear himself at all. So they moved the mic closer to Jeff. Same result. Jeff then played louder and right into the mic, while George was off to the side. Same result. What in the world was going on there?

Something folks who do a lot of recording seem to generally agree on is that a certain kind of tone will cut through and be heard in a complex music environment even at a lower volume. Every tone has three components, a kind of triangle of tone. On the bottom is warmth. We all love warmth. Bass trombonists in particular, like George and Jeff, are especially fond of warmth. That's the foundation of the triangle. In the middle of the triangle is core. And at the top is brilliance. All tone qualities are a mix of these three elements.

Getting back to recording folk, what trombonists seem to have concluded in general is that a sound that has a little more to the core part of the triangle gets heard better and sounds clearer than a sound that has more of one of the others, say warmth for instance. And those with a little more core to the sound don't have to play as loud to come through.

What Jeff didn't say in his story -- which was an amusing anecdote about trying to figure out how the hell George Roberts got heard while Jeff disappeared -- is that he and George generated tones that have different mixes of the triangle elements.

Jeff's sound, commensurate with his 40 years as bass trombonist for the L.A. Philharmonic, was big, beautiful and full of warmth (as it remains today). He can really fill up a room with gorgeous, sonorous sound that is quite wonderful to hear and never loses that quality no matter how hard he pushes it. Jeff's sound is heavy on warmth, with a touch of brilliance and just enough core to keep it sounding focused. George Roberts, on the other hand, had a much smaller and more compact sound that, while lovely in its own right, was very heavy on core and much less so on warmth or brilliance. Listening to George alone, he sounded wonderful. But listen to him next to Jeff, and most folks would probably prefer Jeff's sound as more pleasing and pure.

But the thing is, George's emphasis on core at the expense of warmth and brilliance "projects" far better in the sense that it can be heard and identified in the cacophony of an orchestra performance, at a lower volume, than Jeff's could be. It was the pushing of the core part of the tone that made it project better, though Jeff's sound was probably technically preferable in a purist's sense.

So while we're getting into the weeds a bit with all this inharmonicity of harmonics and such, I'm reminded by Jeff's story that it might not be that complicated. It might simply be that of the three elements of tone -- warmth, core, and brilliance -- projection is a manifestation of emphasizing core over the other two. I say that because I consider "projection" to simply be the art of being heard at a particular decibel level in the context of complex music.

Anyway, that just came to mind as I read this thread. The story was great and we had a good laugh at the mental image of Jeff trying like hell to figure out why he couldn't be heard next to George even when he was playing directly into the mic and playing louder than George. But I suspect the answer to projection lies somewhere in that story.

[ithinknot]

To be fair, the original question was about physics, and (at least to me) the question is interesting precisely because musically/artistically defining projection is indeed quite easy. At the pornographic "I know it when I see it" level, I think most of us would be on the same page, and warmth/core/brilliance can be discussed in a shared and meaningful way despite the enormous difficulty of explaining what those things might actually be. You can't EQ JR into GR, or vice versa.

But the comparison certainly reminds us how important it is to hear people live. In my neck of the woods, there's a particularly prominent jazz player. On record, their tone seems like the medium for highly technical musical ideas - of which there are plenty, so we're all good - rather than a swoon-inducing thing of beauty in-and-of-itself. But in person, cheap seats/good PA/bad PA/no PA, that sound just comes and finds you and hits you between the eyes, without being specifically narrow or bright (and still has the same effect past the 2hr mark). The package makes sense in 3D, and that's cool.

[timothy42b]

I had a hearing test last week. Turns out I'm normal to 3000 Hz, at 4000 Hz I start falling off a cliff.

I went to an audiologist because I was starting to ask people to repeat what they said, exactly like my friends who are genuinely hard of hearing.

But actually I can hear some conversations very well, and others indistinctly. I don't have the right terms to describe a voice - this may be what singers call ping or twang - but if a voice is oboe shaped as opposed to flute shaped it is much more clear to me even at lower volume.

I did some youtubing on singers, looking for good descriptions of vowel shaping and pitch. There are some people posing as experts who seem shockingly uninformed. But one that seemed reasonable said that a sung pitch has integer harmonics. A vocal tract does not; it has resonant frequencies called formants, which you can adjust. You adjust the first two formants to reinforce the appropriate sung harmonics by shaping the vowels. (If you are singing a note between the two formants, you change the vowel so that the second formant matches an upper harmonic of your voice.) Someone named Berton Coffin built a contraption to play pitches into your mouth so you could hear what pitch you were matching.

[Windmill]

If I can add my pinch of salt here... I recently experienced that what we hear behind the bell as a player is not related to what's the audience hearing. When I switched to the Vocabell, which is knowned (or at least expected) to project like a Panzer, I found myself hearing less of my tone while playing but people in front of me all agreed that they get more sound volume from me. Which is a bit destabilising!

[brassmedic]

A friend is a piano tuner (and trumpet player) and has an app that can read the intonation of every harmonic individually, regarding piano tuning. We've had discussions about this before but I'll have to ask him if it can do the same for brass sound.

But I'm at ITF now and won't be home for a while.

You know how some players have sound that is impossible to tune to? I don't think it would be that way if all the harmonics lined up perfectly.

So I messed around with the Audacity app, capturing trombone notes from YouTube and plotting the spectrum. I need to do it a lot more, but so far the peaks appear to be pretty close to their theoretical positions. But yes, there are small differences in the tuning of each partial, and one player had a very strange double peak on the first 2 partials. What I noticed so far is that in what I consider to be an "orchestral" sound, some of the upper partials tend to be slightly flat, whereas in what I consider to be a "commercial" sound, they are slightly sharp. But I would need to check out a lot more examples to be sure that's not a fluke. It's hard to find recordings on the web where there are no other sounds besides the trombone.

[LeTromboniste]

What I noticed so far is that in what I consider to be an "orchestral" sound, some of the upper partials tend to be slightly flat, whereas in what I consider to be a "commercial" sound, they are slightly sharp. But I would need to check out a lot more examples to be sure that's not a fluke. It's hard to find recordings on the web where there are no other sounds besides the trombone.

Yes, the theoretical values are for a tube of negligible diameter. In the real world, the diameter of the tube is in a significant proportion to its length (similar phenomenon to the extra thick bass strings of a piano), which causes some inharmonicity, plus the fact that it's not a straight cylindrical tube in practice. A narrower tube has a slightly lower fundamental and wider-spread overtones than a larger tube of the same length. That would line up with your observation that orchestral players have flatter higher harmonics than commercial players.

[Matt K]

The STS has a bunch of videos of orchestra excerpts with only trombone or trombone and tuba