Tweaks for a 186?

[josh_kaprun]

I have noticed that, here on Tubenet, people are quite frequently referring to getting their horn tweaked in various ways. I was wondering if anyone knew of any good tweaks for a Miraphone 186 BBb-4u.

Recently, I have noticed that my rotors are just not keeping up with me when I'm going through faster exercises (the fast chromatic scale from the William Bell Routine). So, one thing in particular I would like to do is to increase the spring tension on the rotors so that they will move faster. What exactly is the procedure for this?

[MartyNeilan]

Having the horn professionally chem cleaned and then keeping the rotors lubed with the lightest Hetman's that works will probably do a lot more for making them faster than just monster spring tension.

Marty "who has done both, and learned the hard way" Neilan

[iiipopes]

My tweaks include repositioning the leadpipe and receiver for my slight overbite, repositioning the paddles for my short pinky, which actually included narrowing the spread and lengthening the 1st paddle more so I didn't have to angle my wrist, repositioning the thumb ring so it just barely clears the 2nd valve slide, and putting a little bit of golfer's lead tape on the receiver to get a balance between slotting flexibility and secure intonation.

Bloke on the Holton 345 thread commented on adjustments (whether intentional or unintentional) to the outer bows to get certain partials into tune. I'm looking forward to experimenting to get those damned fifth partials C, Db & D into tune. Everything else is great, and for intonation I'm spoiled on my Besson.

I am probably one of the last persons who prefer the older "S" arm linkage. Mine is relatively quiet for its age. I like neoprene rotor stops instead of the cork, as I can take an exacto knife and shave to a finer tolerance to get exactly the right throw, and they stay that way.

For other tweaks, including replacement bells and addition of 5th rotors, see Dan @ thevillagetinker.com

[jmerring]

Forgive me for stating what probably is obvious, but I sped up my rotors a little bit by very carefully and infinitesimally opening the back caps (under side of the rotors), so that each gave me the feel and speed I wanted. Of course, the horn came from Matt Walters in absolutely perfect condition, but I still played with the caps a little bit.

Jim (obivousman)

[Dan Schultz]

Other than doing the obvious things like making sure the horn isn't leaking, the rotors are sealed, and the bores are clean, I like to put a borescope down the leadpipe to have a look at EXACTLY what the rotors are doing instead of depending on the marks on the back plate and rear rotor shaft. Just dab or rotor mis-alignment... either rotary or axial can make a horn perform a less than optimum levels. If you compound a dab of rotor mis-alignment by four (or five), the results can be disastrous.

[pulseczar]

My horn had slow valves once. I took paper towels and pipe cleaners soaked in naphtha, wiped out all the old oil, then added 3-in-1 oil. It worked. The 3-in-1 evaporates quickly, but rotor action was much faster and crisper.

[Rick Denney]

This isn't a conduit that is moving a quantity of water from one place to another. It is a tube that is conducting a sound wave in a specific direction. I would bet that a misalignment of up to 3/8 of the total tube volume cannot even be noticed by nearly any player.

Funny you mention the word "impede" but then give an example of continuous flow.

In electricity, DC (direct current) sees only resistance. AC (alternating current), on the other hand, sees resistance and reactance, which together become impedance. Reactance is a frequency issue, where the current or voltage is impeded by the electromagnetic effect of an electric field, which rings a little askew from the frequency of the electricity and thus alters the resonance.

Blowing air through the instrument and noting the (minimal) resistance from a slight misalignment doesn't mean that the misalignment won't have an effect in the frequency domain.

That exposed edge of valve will reflect sound waves back into the tube. If the reflected pulse fills in the vacuum between the pulses, it will undermine the ability of that vacuum null to reinforce the next pulse, which is what makes the tuba resonate. When the air is moving fast, it has a lot of energy and reflections strongly, and the air moves fast in the forward direction once each pulse, and fast in the reverse direction once each pulse. Thus, even an edge exposed downstream from the mouthpiece can cause reflections, though there is enough "DC" in the mix to make the reflections in the forward direction more significant.

Smooth bumps probably don't have much effect, but edges can. I can find a hidden nick in a fiber-optic strand using a time-domain reflectometer, which just looks for the reflection back from the nick in the frequency domain.

And since the surface of the tube provides the source of impedance, an edge that covers nearly half the diameter of the tube (as in the case of a misaligned port) can have a subtle but significant effect.

There's a reason why Matt Walters adjusts response of instruments using a sharp broach applied to the tips of tuning slides. The effect is subtle but real.

When I move my rotary valve part way (to simulate your 3/8 blockage), I definitely, positively feel and hear the difference. When I play my 621, I'll occasionally notice a complete loss of centered resonance, and sure enough I've let my thumb rest a little too hard on the fifth-valve trigger. It doesn't take much.

Rick "who doesn't model AC using DC" Denney

[josh_kaprun]

ok, no sparring. this post is about doing tweaks, not arguing about impedence.

[MikeMason]

When it comes to playing music,superstition may indeed be more important than science.I wonder if there is a scientific test to prove it?...

[WakinAZ]

I think whatever real dialogue has happened in a thread is pretty much over when the dictionary definitions start ...

Eric "yawn" L.

[jeopardymaster]

I won't dive into the previous subject matter. The original question was about tweaks to a 186. Some time ago I opened a dialog about my problem with the 4th slide pull on my 186 BBb. Intonation on low B and E natural was poor, and because of the location of the 4th valve slide, pulling it is not practicable. So I had Dan Schultz put a kicker on the second slide. Works like a charm for me. You can see the work he did on his website.

[Rick Denney]

1. Impede: To retard or obstruct the progress of; block - The American Heritage Dictionary

2. The air isn't moving that fast. As noted in my example, you are not pushing that much air through the horn to begin with. One of the biggest problems horn players apparently have is the impression that they are actually moving a considerable amount of air. The amount of air moving through a horn is actually negligible.

3. In fact, I don't believe it is even possible to measure the air flow from the bell end of a tuba.

4. The exposed edge MAY reflect sound waves back into the tube and PERHAPS fill the vacuum between the pulses. That is a big "if" in that sentence.

5. I submit that the effect of any such Walters adjustment to the tuning slides is purely placebo. The problem is that there is no possible way to prove it one way or another. It would require two horns that play identical and this being the only different modification.

6. [My partially moved valve] This is hardly conclusive. There would need to be a double blind test set up. The problem is noted above in finding two horns with the same response and then having the valve adjustment be the only difference.

7. We are talking about science not superstition. The problem really relies in finding a way to remove the human out of the equation for a valid testing protocol.

8. This in many ways is like the argument that swimmers make that shaving the body hair off has an impact in their speed. The ability of body hair to increase the resistance of a human moving through water is less than minimal. If the human were moving through water at 800mph there may be some impact, but not at the speeds of the best swimmers in the world.

I've numbered your responses to minimize all the HTML tags.

1. "Impedance", in electrical terms, consists of both resistance and reactance. Resistance is just what we think it is--holding back a continuous flow. Reactance is holding back a particular frequency or range of frequencies. An electrical capacitor, for example, is a discontinuity that won't pass DC at all, but it will pass AC at the right frequencies. An inductor is an invisible short in DC, but will impede AC and the right frequencies. You can't make an argument that something has no impedance by looking at continuous flow only, just as you can't measure the effect of a capacitor or inductor using only DC.

2. The air actually is moving quite fast, but for short distances. The vibration pulse is a series of pressure fronts separated by vacuum spaces. The the vacuum causes the molecules to rush together, which they do just in time for the next pulse to arrive, reinforcing it. Then, the pulse passes and the molecules rush apart again. The molecules don't move fast through the horn (your point), but they do wiggle back and forth fast enough for the pressure wave to travel through the instrument at 1100 feet per second. That's fast.

3. Again, you are trying to measure a frequency issue using a continuous flow tool. You may not be able to measure DC at the end of that resonant circuit, but you'll sure as heck be able to measure AC, as long as you use the right tool. If you hear sound coming out the bell of a tuba, you have a series resonant circuit, even if no air passes through the instrument at all. And you'll have high velocities as the sound pressure waves propagate through the space of the tuba.

4. Yes, I did use the "if". I was not arguing that the edge would or would not have an effect (though I think the empirical evidence is clear enough). I was arguing that the slow continuous flow of air through the instrument didn't refute its effect.

5. We have had one person on Tubenet complain that Matt reduced the playability of the instrument making such adjustments without his knowledge or approval. How did he know? Again, I'm not arguing that it always has an effect--that depends on the frequencies involved and the position of the edge. I'm arguing that such an effect is scientifically plausible. You are arguing that it is not scientifically plausible (a "placebo effect").

6. A double-blind test? Please. I'm not talking subtleties here. I'm talking a sudden and noticeable (and unexpected) degradation in sound and resonance, prompting an immediate assessment of what was wrong, and discovering that I was accidentally nudging the valve trigger. It has happened a number of times. I am not imaginging it. Try it yourself.

7. The fact that the frequency domain requires different measures and descriptions than does continuous flow is not superstition.

8. Only beginning swimmers and wannabes argue that the shave-down reduces friction in the water. The good swimmers (and, as a former long-distance triathlete, I've known and trained under a few Olympians) argue that the shave-down improves their feel of the water. In swimming, efficiency is all, because water is dense and presents high resistance. The best swimmers naturally know how to make the smallest hole possible in the water, and how to lengthen and narrow their "hull" to go faster. They naturally feel where the water is flowing past their bodies in laminar flow, and where they are creating efficiency-robbing turbulence. The shaved skin is more sensitive and enhances that feel. That you and I don't have those sensibilities doesn't mean they don't exist. There's got to be some reason that champion swimmer could swim two laps in the time it takes me to swim one, and fitness doesn't explain it all by a long shot. In fact, they argued that I had to be superfit to spend so long fighting the water as inefficiently as I did.

By the way, stretch plastic wrap over the end of your bell tightly to fully resist all continuous flow, and then blow a note. For a brief time, you'll get a note, until the continuous flow resistance is so high that it presents too high an impedance. Before that happens (and it will happen sooner than you think), the sound will still come out the bell--the plastic wrap is almost transparent in the frequency domain. That will highlight the contribution of and differences between resistive and reactive components of impedance.

Rick "who doesn't measure reactance with a DC voltmeter" Denney

[Dan Schultz]

Just dab or rotor mis-alignment... either rotary or axial can make a horn perform a less than optimum levels. If you compound a dab of rotor mis-alignment by four (or five), the results can be disastrous.

I disagree with this. Misaligned rotors may look problematic, but unless they are GROSSLY misaligned will have no effect on performance.

Harold... maybe you need to define what you consider to be GROSS misalignment. It has been my experience that ANY misalignment will produce a sharp edge in the sound column. Problems with rotor alignment are no different than with piston alignment. It has NOTHING to do with air volume. Any sharp edges protruding into the sound column will affect performance. Just for the heck of it, take the bumpers out of one your rotary horns. I'll guarantee that it will play like crap... aside from being really noisy. Take the felts and corks out of one of your piston horns and try to play it. Both the radial alignment AND the axial alignment are important in both rotary and piston valves.

[Rick Denney]

ok, no sparring. this post is about doing tweaks, not arguing about impedence.

Sorry, too late.

Remember, though, that nobody owns the thread. Threads wander around, and sometimes nuggets emerge as a result. Sometimes not. Skip past it if you aren't interested.

Rick "thinking a little frequency-domain science won't hurt anybody" Denney

[iiipopes]

Hmm. The flat 5th partial syndrome. After reading bloke's comments, last night I made some observations and measurements. A BBb tuba is roughly 18 feet long, give or take a few inches to compensate for bore, flare, etc. 18 feet is 216 inches. 216 divided by 5 is about 43 and a fraction. So I measured 43 inches down from my bell rim. On a regular conventional bell 186 that distance is right about the big ferrule attaching the bell stack to the bottom bow. On mine, with the shorter retrofitted upright detachable bell necessitating a longer main tuning slide, that puts it just under the ferrule. As a result, the node for C, being a whole step lower pitch, is under the ferrule starting into the bottom bow curve, at about 48 inches.

Then I got out my tuner. Surprise, surprise! D is flat as you might imagine. But Db is only slightly flat, and C is right on.

So, I wonder if the bell stack proportions and bottom bow were re-engineered to either change the taper slightly at that point, or redo the positioning of the ferrule, if that would solve the flat 5th partial problem? This is since the ferrule adds mass and creates a mechanical incontinuity, and the mantra, added mass damps vibration and changes characteristics (mechanical impedance, as described above).

OK, I also know that the terminal node is actually slightly beyond the rim of the bell, effectively slightly lengthening the horn, but even allowing a couple of inches for that, on my particular example, the D node is still at the ferrule and the C node is still along the bottom bow. On a conventional 186 BBb, they are all in the neighborhood of the bell stack ferrule.

Something to ponder.

[The Big Ben]

ok, no sparring. this post is about doing tweaks, not arguing about impedence.

Come sit beside me, grasshopper. Listen and learn as the tuba men joust about. It is all a part of the vast knowledge that must be acquired to be rightly called a tuba man.

[MaryAnn]

I was just explaining last night in a band officer meeting why the (french) horns should not be seated in front of the bass drum or the timpani. Unless you have sat there and felt the whack on your chops when the percussion gets excited, you wouldn't believe what disturbances in the frequency domain can do to the waveform inside the instrument.

MA

[Sam Gnagey]

It's not exactly a tweak; but I've had good success exchanging the original Mirafone bells for the old Conn monster Eb bells. If you looking for a more robust "American" sound, that'll do it for you. It's also a great fix if the Mirafone bell is trashed. I have a few of those old Conn Ebs sitting around if anyone needs a bell switched out on their Mirafone tuba. It'd probably work on some of the Cervenys, Meinls, Alexs and other Euro horns too.

[josh_kaprun]

What exactly is the different between the stock Miraphone bell and the old Conn Monster Eb bells that makes a change in the sound? Does it affect the way the horn plays? projection? tuning? weight?

[Tom]

Regarding changing bells...

If there isn't anything wrong with your current Miraphone bell (especially if it is the older smaller bell), don't change it.

Along the same lines, if you have the smaller leadpipe on your tuba, don't replace it with the larger design unless you have to (ie red rot).

Maybe it's just me, but the 186 never struck me as a tuba that needed much "tweaking"