Slotting?

[Geordie]

I read here about horns with wide slotting, narrow slotting and even soft slotting. Not seen any definition of slotting. Seems to refer to how readily, or not, notes can be accessed with the appropriate slide, air, tongue and embouchure combination. Is that broadly your understanding of the term?
Is it heretical to suggest that slotting is far more to do with the player than the horn - assuming it’s structurally sound?

[Burgerbob]

There's definitely a player element to it, but each horn slots differently no matter the player.

I guess a very simple explanation is "how easily a trombone can slur from one partial to another," though that's leaving out a lot.

[elmsandr]

Think of it also like this, how far can you bend a pitch without moving anything? Some horns force you in to a narrow canyon on a given pitch, others are like a valley between soft hills.

There is certainly an interaction with the player, but for a given player, there are differences between horns as well.

Cheers,
Andy

[Kbiggs]

There's definitely a player element to it, but each horn slots differently no matter the player.

I guess a very simple explanation is "how easily a trombone can slur from one partial to another," though that's leaving out a lot.

I would to that: How well a player can find the center of the pitch within a partial on a given horn. A player can slur from one partial to another easily, yet be unable to find the pitch center easily, or the opposite: A player can find it difficult to slur from one partial to another yet find the pitch center easily. I think that switching the variables can also apply: easy to slur and easy to center the partial, or difficult to slur yet difficult to find the partial (although that last seems unlikely).

Obviously, it’s a very subjective measure, and depends on the player, how fresh or fatigued they are, the mouthpiece used, the acoustics of the room, relative temperature and humidity...

[harrisonreed]

It has to do with the horn and the leadpipe and the mouthpiece. There are two ideas here. You can have horns where the whole set partials are wide or narrow. On a horn with a narrow set of partials, you go flatter and flatter the higher up in register you play. But usually when people talk about slots, they are taking about individual slots, and not the compete set. For the slots themselves, I think of it like this:

There are some horns where the slots are wide and shallow. You can easily come in too low or too high (cents, not a different partial) on the note you shoot for, and your chops will have a huge influence on the pitch variation. Someone with really accurate chops may love a horn like this, especially in the jazz world. You easily hit the note you want and you can color it like crazy. It is more difficult to do a lip trill or shake, since the slots are not well defined.

There are horns with narrow, deep slots. Accuracy is needed to pick out the note you want to play, but once you have it, you are locked in. Lip vibrato is difficult. Trilling is difficult because the next partial feels far away.

The are horns with wide, deep slots. Chop accuracy is not as important, you sort of just blow the pitch and you're locked in on it. Trilling is easy because each slot is touching the next. You can push lots of air and make things happen without really coloring the tone.

I don't think any horn maker is going for the other kind, narrow, shallow slots. That would be a nightmare to play, but maybe that is what sackbuts are like.

This topic is deep and not very objective. I have always sought out trombones with wide, deep slotting. They are the easiest to play. My Edwards has the harmonic brace, and the whole design of that device is to try and influence the slots. It works. Wrapping the throat of the bell does too. So does the backbore of the mouthpiece and the leadpipe.

Pretty much all the stuff people do with custom trombones is an attempt to influence how the thing slots.

None of it matters if the player is not actually digging into the horn and really playing it. There is also the "chest voice" vs "head voice" playing style, where they will perceive how the horn slots in a different way. Anyone remember me going back and forth with Sam Burtis over type I type II playing? Bousfield has noticed this too and calls it head voice / chest voice.

I think the chest voice players get the most out of these gear modifications to affect slotting.

[baileyman]

I suspect the "wide valley gentle hills" type slot is created by a horn having more internal reflections than another. Every transition creates a reflection of some magnitude, some much greater than others. Some of the big ones could be

end of mouthpiece
end of leadpipe
end of inners and crook diameter change
slide joint
tuning slide ends
bell end

It seems that Bach rather manipulated these things to get his sound and behavior. If I recall, the slide joint is rather more disruptive in his design than others. I would expect a perfectly smooth ideal trombone with Euler curve transitions to slot unbelievably hard. Maybe one of our tech oriented people has a thought on this.

[Elow]

It seems that Bach rather manipulated these things to get his sound and behavior. If I recall, the slide joint is rather more disruptive in his design than others. I would expect a perfectly smooth ideal trombone with Euler curve transitions to slot unbelievably hard. Maybe one of our tech oriented people has a thought on this.

What do you mean by euler curve, wikipedia said a curve that changes in relation to its curvature... and i understand but i don’t understand. What about something like bac’s side crooks?

[baileyman]

The Euler can be used to connect one line to another matching the tangents at the beginning and the end. Draftspeople use one they call a French curve.

So for instance if mouthpieces or leadpipes had a little tangent matching curve at the end, the horn would be smoother.

I think Bach's crook may be like that, sure.

[timothy42b]

The physics definition:

The Q factor is a parameter that describes the resonance behavior of an underdamped harmonic oscillator (resonator). Sinusoidally driven resonators having higher Q factors resonate with greater amplitudes (at the resonant frequency) but have a smaller range of frequencies around that frequency for which they resonate; the range of frequencies for which the oscillator resonates is called the bandwidth. Thus, a high-Q tuned circuit in a radio receiver would be more difficult to tune, but would have more selectivity; it would do a better job of filtering out signals from other stations that lie nearby on the spectrum. High-Q oscillators oscillate with a smaller range of frequencies and are more stable. (See oscillator phase noise.)

Seems to me slotting and Q factor are terms for the same thing.

[Geordie]

SNIP

There are some horns where the slots are wide and shallow. You can easily come in too low or too high (cents, not a different partial) on the note you shoot for, and your chops will have a huge influence on the pitch variation. Someone with really accurate chops may love a horn like this, especially in the jazz world. You easily hit the note you want and you can color it like crazy. It is more difficult to do a lip trill or shake, since the slots are not well defined.

There are horns with narrow, deep slots. Accuracy is needed to pick out the note you want to play, but once you have it, you are locked in. Lip vibrato is difficult. Trilling is difficult because the next partial feels far away.

The are horns with wide, deep slots. Chop accuracy is not as important, you sort of just blow the pitch and you're locked in on it. Trilling is easy because each slot is touching the next. You can push lots of air and make things happen without really coloring the tone.

SNIP

My question is then why would anyone want a tbone that didn’t have wide deep slots? Is it the case that the player’s technique affects which horns have wide deep slots for them? Does this mean we cannot generalize about what make/model is a ‘good’ slotting horn as it’s an individual thing?

[BGuttman]

Beginners do better with deep slots. This helps train them to play in the middle of the tone.

I suspect how wide the slot is would be dependent on the overall design. You don't build a horn for this aspect; it usually comes "for the ride".

[Thrawn22]

Try not to think about it.

[mfturner]

As an adult beginner with a pBone and a Conn 24H to compare, I think slotting is a very real thing. As an engineer I would have said the pBone has a very low Q, I can be sloppy with slide placement and force the notes to what I want lipping them up or down. Whereas the Conn has a very high Q, my lips make a ratty in- between partials sound unless I get the slide in the correct placement (or relax my embouchure and let the note go flat or sharp to match the slide placement). I prefer to practice with the Conn because of this, but the pBone rides in the minivan for lunch breaks at the office. I suspect the difference in geometry and materials both play a role, although air is much less dense, more compressible and elastic, than even plastic, so geometry maybe more so. The pBone definitely stretches octaves (flat for low notes, sharp for high), and doesn't let me play as high (which I think is because of the low Q, but could be me). As I said, I'm a beginner, so I could be wrong about any of this, but I don't think so.

[ithinknot]

Seems to me slotting and Q factor are terms for the same thing.

Yes, for the computer simulation. But what we experience and describe as slotting is definitely influenced by what we experience and describe as resistance. And vice versa. (And a pile of other things.) I know that doesn't help.

Is it the case that the player’s technique affects which horns have wide deep slots for them? Does this mean we cannot generalize about what make/model is a ‘good’ slotting horn as it’s an individual thing?

Resistance and Q are properties that can be measured in isolation in (scientific, but musically unrepresentative) absolute terms. But the player's technique will affect what they like. 'Good' doesn't mean much, but it's still an implied comparison with other horns with a lower Q factor. Harrison's language is more useful.

In the extreme high register where slotting differences really start to show, there's definite (artistic as well as scientific) good and bad. No horn has absolutely consistent slot width and depth AND intonation above Bb4. There was the other thread about high E and Eb. If a horn won't let you lock in high E, or G, instead flipping between adjacent partials, that's 'not good'. But a horn that locks one or other of those notes especially strongly will probably have other problem notes instead. In this region, a high Q is going to show up other problems/inconsistencies. The best you can hope for is that partials 8-10 are reasonably well tuned, and that above that there aren't pitches where the horn's preferred resonances actively divert you away from the target note.

[timothy42b]

My question is then why would anyone want a tbone that didn’t have wide deep slots?

You can't have both. There is no free lunch. Deep slots (which means stronger response) are by nature narrow and vice versa.

If you play exactly in the center of the slot those two different cases may be pretty close. If you are a beginner you are not going to be precise about that. If you're more accomplished you may have tonal reasons for playing above or below the pitch center.

There's an interaction with the partials here. Remember that partials do not line up the same way overtones do. Overtones are always mathematically in step, partials are based on the construction and compromises of the horn. So it's at least theoretically possible that a narrow slot will miss an upper partial - or it's possible I guess that a narrow slot depends on an upper partial.

[Geordie]

My question is then why would anyone want a tbone that didn’t have wide deep slots?

You can't have both. There is no free lunch. Deep slots (which means stronger response) are by nature narrow and vice versa.

And this is why I’m confused. At least one post suggested it’s possible. In the interests of a more concrete conversation, does anyone think there are there any instruments with wide deep slots?

[elmsandr]

You can't have both. There is no free lunch. Deep slots (which means stronger response) are by nature narrow and vice versa.

And this is why I’m confused. At least one post suggested it’s possible. In the interests of a more concrete conversation, does anyone think there are there any instruments with wide deep slots?

Remember that these are all subjective discussions. We don't have a slot measurement device that can tell us how our chops feel. Some feel wider and deeper to the others, but this is all a matter of degree. Maybe wider and deeper than others and the 'slopes' out of the valley feel like they make more sense to what you expect to happen. Again, this isn't an exact measurement, it is a feel relative to the expectations of the evaluator. If we could make an exact model with measurements, maybe we would find that they are all on a continuum. Who knows? I would think that one could make a career figuring out how to measure and report that. However, I don't think anybody would pay for it.

Also, NONE of the discussion of what the slot feels like in terms of Depth and Width have been compared yet to what the horn SOUNDS like. Sure, you may want wide and deep, but what if it sounds like playing a tin can? There's probably some trade-offs there that we would have an even harder time quantifying.

Cheers,
Andy

[Kbiggs]

Remember that these are all subjective discussions. We don't have a slot measurement device that can tell us how our chops feel. Some feel wider and deeper to the others, but this is all a matter of degree.

[...]

Also, NONE of the discussion of what the slot feels like in terms of Depth and Width have been compared yet to what the horn SOUNDS like. Sure, you may want wide and deep, but what if it sounds like playing a tin can? There's probably some trade-offs there that we would have an even harder time quantifying.

Cheers,
Andy

This.

I would change: “...what the player SOUNDS like on that horn.”

I would add: Everything you change on a horn affects the way it plays and feels.

[mfturner]

There is physics and acoustics research ongoing that includes stuff like this, such as the UNSW pages here as a good introduction for those interested:

https://newt.phys.unsw.edu.au/music/

I agree that this won't help you sound better, and at the end of the day that's what matters. Feel and sound from trying different horns are better guides I think.

For the record, I think it's likely that you can have all 4 shapes of shallow, deep, wide or narrow resonance in a brass instrument (and that resonance Q changes with harmonic - undesirable shallower/ narrower happens in all brass instruments as you get higher harmonics from the unsw plots), and that instrument mass, bore size, mouthpiece size and shaping, and bell size and shaping all play a role (along with many other things). A very complex problem with a lot of design variables and constraints. For example, I love how light the pBone is compared to the 24H, but that may partly be why I sense sloppy slotting in the pBone, and why I can hit 2-3 partials higher with the 24H (among other things, this is just an example of a trade off).

[imsevimse]

Try not to think about it.

I agree. This is not something I ever think of as a problem. To me it is just the character of the horns and what makes them interesting to play. I think it has a lot to do with the player. If you have a solid emboushure you can make any style of horn work for you and a flexible horn then lends itself to more colours. A horn that slots more easy might instead be the better horn for a studio player or commercial soloist who eats the mic

/Tom

[harrisonreed]

This is a funny video, not very informative, but hits on part of what slotting is:

[baileyman]

Meanwhile, on formants, the trombone formant is like an overlay on top of some underlying "pure" sound. It raises some frequencies and lowers others, and it does that for the same frequencies no matter what note is being played.

It's this fixed coloring that I think we perceive as different horns having a different sound. I have not seen discussion about where the formant comes from, but I suspect it has to do with the design disturbances in the transitions. To the extent these guys form internal reflections, I'm guessing the sum of them may create the formant.

You know, I suppose this would only be true for notes in one position. Seems like there should be a different formant for every slide position because of the changing locations of the reflections.

[harrisonreed]

The formant has to do with your mouth and throat cavity size, and probably is affected by the mouthpiece which dictates your range of jaw movement. The formant is what changes vowels in singing and speech, and has an effect on the overtones. I don't think it has to do with the trombone itself. The formant needs to change with the register, and that's why you hear teachers talking about "toh" and "tee" articulations. They don't actually know the whole story of why they are giving that advice a lot of the time.

Don't take my word for it: https://en.m.wikipedia.org/wiki/Formant

Here is Sam Burris describing a technique to understand and control the formant:





DISCLAIMER: I do not personally agree with his connection of buzzing into all of this, though it obviously is working really well for Sam. However the throat singing as it relates to the shape of the throat and mouth and the overtones it influences is clear. A great way to understand what the formant is, at least in singing. It's why some singers sounds crazy good.

[timothy42b]

It's this fixed coloring that I think we perceive as different horns having a different sound. I have not seen discussion about where the formant comes from, but I suspect it has to do with the design disturbances in the transitions.

I do not think this is the case, but we may be saying the same thing in different words. My concept is a little different and I haven't seen anybody else who agrees, although there is a hint in Benade's Fundamentals.

Here is what i think causes different tone in different horns.

The buzz inputs a fundamental frequency and a range of upper overtones, all of which are forced to be mathematically related.

The fundamental and the overtones are stabilized and reinforced by the horn.

The horn has a set of partials, which are not forced to be mathematically related as exactly as the overtones. This is due to the effects of construction: bends, changes of bore, obstructions, bell flare, leadpipe, etc. On some horns they can be close, on others considerably different. A trombone is not a simple cylinder or cone, but collection of shapes.

Where overtones and partials coincide, reinforcement is strongest.

Since they don't line up exactly, playing above or below pitch center (center of the slot) can cause different overtones to be reinforced, and affect the tone. The width of the slot changes how easy that is to do, but also the strength of the reinforcement.

[baileyman]

It's this fixed coloring that I think we perceive as different horns having a different sound. I have not seen discussion about where the formant comes from, but I suspect it has to do with the design disturbances in the transitions.

I do not think this is the case, but we may be saying the same thing in different words. My concept is a little different and I haven't seen anybody else who agrees, although there is a hint in Benade's Fundamentals.

Here is what i think causes different tone in different horns.

The buzz inputs a fundamental frequency and a range of upper overtones, all of which are forced to be mathematically related.

The fundamental and the overtones are stabilized and reinforced by the horn.

The horn has a set of partials, which are not forced to be mathematically related as exactly as the overtones. This is due to the effects of construction: bends, changes of bore, obstructions, bell flare, leadpipe, etc. On some horns they can be close, on others considerably different. A trombone is not a simple cylinder or cone, but collection of shapes.

Where overtones and partials coincide, reinforcement is strongest.

Since they don't line up exactly, playing above or below pitch center (center of the slot) can cause different overtones to be reinforced, and affect the tone. The width of the slot changes how easy that is to do, but also the strength of the reinforcement.

I think we're likely on the same page. The trombone is a filter in addition to impedance matching and whatever it does massaging the partials around.

I have seen acousticians talking about "the trombone formant" as a characteristic sound that we recognize as "trombone". And the discussion I recall indicated the upper frequencies emphasized are often not in what one would think is in the overtone series. And some of those happen all the time in all trombone notes. That's why the formant is "characteristic". Somewhere on paper I have a frequency plot of one of these things, but good luck to me finding it!

My basic thought is that if we had a horn with trombone air column and smoothed joints eliminating as much as possible internal reflections, most all the color would disappear and the thing would slot like crazy.

[TomRiker]

Can't that be tested using a straight bugle and a curved one if the bore and bell are the same?

[timothy42b]

A bend in tubing adds friction to air flow, but appears as a wider bore to a sound wave.

[CharlieB]

I read here about horns with wide slotting, narrow slotting and even soft slotting. Not seen any definition of slotting.

Just in case you got lost in the hills, valleys, canyons, and other metaphors...........
The following is the way slot was illustrated to me, not the way slot is actually evaluated.

Set a tuner on your music stand and play a middle Bb. Then, slowly adjust your embouchure to make the note sharper. At some point, the horn will jump to the next higher partial. (D). Note how many cents higher that point is. Then, adjust you embouchure slowly again to see how flat you can make that Bb, and note the cents where the note falls to the next lower partial (F). Add the two values together.That total range between the extremes of how sharp and flat the horn sounds that note is the "slot." A small number is "narrow;" a large number is "wide." With a narrow slot the horn wants to center on the true pitch. With a wide slot, the horn wants to just get close and make the player do the fine adjustment.
The slot will vary between horns, leadpipes, and mouthpieces. Whether the slot is narrow or wide affects other characteristics of the set-up, such as agility, cleanness of attack, slurring, coloring, etc. For playing Bugler's Holiday, you might want the agility and crisp attacks of a narrow slot; for playing a languid ballad, you might want the softness of a wide slot.

[Geordie]

Charlie B - nice new practical insight for me. I’ll try it on my various Olds and Kings. Thanks.

[CharlieB]

Charlie B - nice new practical insight for me. I’ll try it on my various Olds and Kings. Thanks.

Glad it helped.

[Windmill]

Hi all

Slotting issues is what made me get a new trombone. I was very happy with the King, until the leadpipe cracked in half from corrosion. The lowest half fell through the inner slide and ended on the floor. I kept playing with it for years but i had to struggle a lot to get a proper intonation, cause the slot had become so wide ! And some notes (for example high Ab, middle C, low Eb), mainly on 3rd position, just died. I mean i couldn't find the sound center anymore. So yes, the slotting depends a lot on the leadpipe and backbore shape/lenght i'd say

And i am a big fan of "instant anticipation" right before i hit a first note in a phrase, wherever it is in the range. For me, each note resonates its own way in my body, and is quite comparable to the chest/head voice of singers. For instance, the middle D in 1st is locked it at the height of my teeth, this is my "balance point" around which everything gravitates. Then, every note below that will resonate deeper and deeper in direction of the throat. The middle F in 1st is located in my chin and the low C at the top of my throat. And everything higher will lock in higher in my head... The high Bb in 1st is right above my nostrils, and the double high F in 1st (or 3rd) is between my eyes.

=> It took a long time to experience and get confortable with the "place" of each note in my upper body, but i could memorize these sensations. And when i'm about to play a bote, i quickly remember the sensation it gives me, where it is, and i feel and hear the note already before i play it. Then i'm 100% sure to hit it directly in tune and with a centered sound. This technique also opened my sound like crazy, where it was always too dull and unconsistant. This helped also to get confidence and eloquence in the high and low edges of my range, which were too shy before. And it gets the focus out of the embouchure/tight corners/etc... to focus on the real source and nature of eachother's sound I guess that's in other words what Sam Burtis kinda explain in his cool videos !

[cigmar]

"That total range between the extremes of how sharp and flat the horn sounds that note is the "slot." A small number is "narrow;" a large number is "wide." With a narrow slot the horn wants to center on the true pitch. With a wide slot, the horn wants to just get close and make the player do the fine adjustment."

So what would be considered a small number, and what would be considered a wide number?

[CharlieB]

So what would be considered a small number, and what would be considered a wide number?

As far as I know, there is no slot "norm."
The above is just a way to illustrate slotting and a way to compare one horn to another.

[baileyman]

Well, my little Bachs reliably flatten a half step to middle D at will like a half-step valve, a bit less above, increasingly more below. They don't like to sharpen at all but I force seventh partial often. Every horn I've ever played will flatten a hard major third on second partial.

I wonder if such behavior indicates slotting or is it rather the interaction between mouth resonance and horn resonance and the mass of the lip reed? Perhaps slotting is not so much the width but the perceived centering force or gradient.

[harrisonreed]

I was doing some EQ work, and I noticed something interesting that may be related to slotting. I feel like my horn slots very well. Some of the other performers commented on my sound during the performance that it was very clear and not dark. They also said that they just had naturally dark sounds. We all recorded with the same mics set up the exact same way.

Well, during EQ, I can see the spectrum analysis of everyone's sounds. My sound just shows each note as five or six very bright lines over each of the overtones that makes up the note. The guys with dark sounds show up as maybe ten fuzzy lines over a wider range of overtones, and lots of red haze in between each line. I will put up pictures when I can, but didn't have time.

It got me thinking that maybe what Tim is saying about the overtones is correct. If your horn / face / mouthpiece are locking in on just the core components of a note, and energy is not being "wasted" (I use the term loosely, who doesn't like a dark sound? The other guys sounded great to me) on color in between the main overtones, perhaps that is what produces deep slotting? Or in other words, that is the signature of a horn that really slots.