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It must be really hard or a really stupid question. I suppose how fast isnt a really a relevant question. fast and sound bad would be no good too.

I am still curious though if anyone knows anything.

 

I'll bet there are a lot of variables that might come into play here.
I would think the 'downward' speed would be slower than the 'upward' speed with a stiff spring. Not so much with a lighter spring.
But I never was good with this type of thinking...
Maybe one of our more technical minded members will have some thoughts a little later.

 

The formula is not hard (physics), but finding the correct numbers to insert into the formula is not easy (laboratory work).

The formula for the top repeat rate is that it is proportional to the square root of <the spring stiffness> divided by <the angular momentum of the key>. The angular momentum depends mostly on the pad size and the distance from the pivot.

Usually, the best spring stiffness is found by trial and error (engineering).

 

Thanks. This problem has been keeping me up nights.

 

Its not a stupid question, but its also not a universal answer either.

For the action to open fast enough but not rebound also must not be too heavy for the player, lets face facts, you can put a spring in which exhibits 300 grams of resistance to the movement of the key, but imagine trying to move 300grams of weight with just a finger tip for an hour session of playing. You would have cramps within minutes of playing

I have measured force required to close keys and force required for fast actions, this was done with local musicians, telling me what they like and dislike

A key can close and lift its own weight and be a very comfortable light action with as little as 30 grams of force applied, however the key to pad relationship must be perfect, no ifs or buts """perfect""", as 30 grams is not enough force to seal the tone hole and overcome a pad which closes at one point before another point

90 grams is a nice action, fast with some forgiveness to accomodate very minor discrepancys in closing sequence. Very minor.

120 grams is a fast action, some rebounding can occur, pads closing at one point before another is relly not to much of an issue.

150 grams is uncomfortable to the average player. Heavy feeling to the keywork.(side note, I find a lot of the older yamaha 23's exhibit tensions of around the 150, be that becuase they came out like that or be that becuase repairers have oversprung the action, I cannot answer)

Hope that helps with your question

 

thnks sismo. i glad someone has gone to the trouble to measure and put some numbers to this. what was the typical force an a factory horn?

I see there are too many uncontrollable variables. sismo's approach looks like its much more useful for making a horn playable. force pushing down obviously is dependent on the player and hence uncontrollable. the variable pad contact, spring rate, damping, friction, etc. could probably be estimated/averaged but there would be significant room for variation.

that sort of leads to have you already had a discussion on optimum pad materials and design?

 

The problem is there is no consistency even from a factory.
Lets pick a nice sax 82Z, from the factory Ive found tensions from 60-135, so this led me to the simple understanding that on an assembly line the builder simply kinks the spring, there really is no optimum setting, which is understanable as each spring will have a different tension, each key will offer a different resistance to being moved, the only way to achieve a uniform pressure is with a tech taking time setting each key. Its as simple as that.

As far as sax pad design, I have through negotiation with a manufacturer had my own sax pads made for me, we use close to 2000 plus sax pads a year, they may not work for others, but for me that are exactly what I look for in a sax pad. For the average handy diy person I recommend musicmedic for simplicity of ordering and decent product

 

Say the E key is lifted. I could be wrong but I rather doubt that any player's finger leaves that key before the key fully opens.

Therefore the limiting factor is the speed of a finger.

Curve a hand and place all fingertips on a desk top. How fast can you move a single finger up and down. It's not very fast. I think springs probably move keys considerably faster. Maybe marginal for the low, heavy keys of a bari, with their large angular momentum. But then do you expect to hear an ultra fast, low trill on a bari?

 

But then do you expect to hear an ultra fast, low trill on a bari?

I hope so!

 

I don't have time to figure it out because I am praticing to play fast.

 

now i realize your in CA but its pretty late and your dot is green. so your reading and writing not practicing to play fast.

 

I just love low Bb to B (or even C) trills on bari.... How about we do low B to low C# folks.

There are some things that aren't reasonable -- I don't care who you are.

 

So this is the thread I came up with when researching this question.
I have very high action on my tenor sax I also have more loose spring tension. It pops quickly but I do not have to press hard to get the key to close.
Now my question, unfortunately adds more to the physics. I can play my scales VERY WELL. When I get up to a very fast speed, like 325 bpm in 8th notes, I find that my scales going downward come out fine and is easy. Now on the other hand, when I try and play going up the scales are not even at all and in many cases some notes dont even speak.

Is this a key height or spring tension issue?
*when I play the scales are slower tempos the ascending scales do not have this issue. I discovered I was having this issue at the breakneck speeds.

 

When I get up to a very fast speed, like 325 bpm in 8th notes, I find that my scales going downward come out fine and is easy. Now on the other hand, when I try and play going up the scales are not even at all and in many cases some notes dont even speak.

This just means that your fingers are stronger than the springs (going down, your fingers push the keys down; going up, the springs push the keys up).

An instrument such as the recorder (no springs or pads, just your fingers) will play just as fast in both directions.

 

wow i forgot this one. i suspected that light springs didnt make a real difference in speed because of how fast you can get your finger out of the way. i played one alto at at the repair shop that had much lighter springs than mine. since it was the the techs horn, i bet he spent some time getting it to play so nice with, compared to my horn, lighter springs.

the pad seating issue and pads sismo brought up is interesting too. im surprised a better more forgiving material hasnt been found over the years. its still basically the same as done in the 1920's. maybe somethink that takes a little thermal set coated with teflon.

 

People keep mentioning pads......
Should I be considering my pads as well?
And someone else mentioned my fingers being stronger then the spring tension. Should I lighten my fingers? My fingers are VERY light at the moment? So then should I add more tension to the springs?

HELP!! AHH TOO MANY VARIABLES!!

 

And someone else mentioned my fingers being stronger then the spring tension. Should I lighten my fingers? My fingers are VERY light at the moment? So then should I add more tension to the springs?

HELP!! AHH TOO MANY VARIABLES!!

I just came back from my holiday, and picked up my tenor with slow springs and high action, leaving the Ferrari (best MKVI ever, perfect setup) in the case: all the issues disappeared!

As long as you do not have an immediate comparison, everything is fine.
Pads need to be replaced when they leak excessively.

 

Fingers seem designed to tap down a lot better than they lift up. To do with the curved design and linkage to the forearm muscles that operate them.
So do fingers just prefer a bit of spring tension to help them lift?

Balance in the way the keys are mounted is a very significant factor. Especially with vintage saxes, some springs have to lift the weight of a key a lot more than just rotate it around its pivot. That means that unless the spring is a lot more powerful, it lifts the key sluggishly. If the spring is a lot more powerful, the little finger in particular has difficulty operating it, especially if there is very little leverage where the touch piece is, as is common on non-Selmer vintage instruments. Selmer had an excellent design engineer around Mark VI days, and that set the pattern for most modern horns.

 

The height of action is a factor in how fast a keyboard feels, but a good feel is a combination of spring tension and key touch orientation *in concert* with key height. Key height should be determined by venting/voicing, but of course if a player requests a different venting you'd be unreasonable not to work around that. Often, though, when players feel like it's venting heights that are slowing them down it's actually something else, e.g. a key touch is out of position for that player or a spring isn't tensioned in a way that'd feel better for that player. Common (i.e. recurring) causes for action feeling slow to players are, for e.g., B2 and/or RH F spring tension being too light, Bis and/or C#2 tension being heavier than necessary, G tension having to be too heavy due to octave key sluggishness, low C/Eb touches being either too close or too far away from the pinky, RH thumbrest position being wrong for that player, even things like the strap ring's orientation causing hand positions to be awkward for that player mechanically. Usually it's not as invasive a question from a repair point of view as moving a strap ring, but the main point is that when it comes to improving feel/action it's easy to overemphasize key heights when actually a tweak (or a few minor tweaks) to spring tension and keytouch position can radically change a player's perception of comfort/speed.

 

Yes, I use teflon sheet, and a combination of different lubes that mix together well. What lube depends on what part of the horn, in part, and whether for a pivot screw or rod screw.

They make a difference, but less than properly fitting tubes and properly fitted keywork overall. I've also seen goofy uses of teflon that actually create friction rather than reducing it. Any contact creates friction, obviously, so if you're using a special material to minimize it you wouldn't want to use it in a nonsensical way.

Teflon compared to traditional cork, used the same exact way, seems to reduce friction by about 50% -- this is just a casual observation.

Teflon's handy for a bunch of different little idiosyncratic things that can affect player perception and "feel." One example's when, on a modern tenor, the G feels "squeaky," like it has a click, and it's due to the cork touch sort of squeaking against the cup below it. Sometimes players feel this and it feels to them like the pearl is loose. A good player will definitely notice it, like the proverbial pea in the proverbial princess's bed. A little teflon landing pad between the cork foot and the cup and the pea is gone. Something as inconsequential as that can actually be a big distraction, or the removal of one, for some players.

 

Palo,

How great is the influence of lubrication and sliding surfaces? Do you use Teflon sheet and low viscosity synth lubes?

 

what about the length of the levers? the distance from the hinge to the finger touch in relationship with the hinge to the pad cup? all those angles and lever/pivot distances?

 

All these distances and masses are part of the calculation of the angular momentum.

A visual demonstration of angular momentum: Have you ever seen an ice skater making a slow pirouette with the arms stretched out? And suddenly spinning much faster when they pull their arms close to the body? What they are doing is reducing the angular momentum and since the rotational energy is the same, they rotate faster.

 

So, let's say someone was creating a sax for the 21st century and it was important to really be able to open/close pads quickly.

Would you think that we would then have electromagnetic 'pads'. Our fingers would simply close/open a circuit controlling these electric pads.
There would not be any springs involved at all just floating or spinning pads in electromagnetic fields.

The control could be much more ergonomic when there was no mechanical connection between controls and pads.

 

Ever play a WX7 or similar wind synth? I find the lack of feedback and the instantaneous response of the keys to be a detriment.

I'll stick with the old-fashioned sax.

"I'm happy with things just the way they are..." my mantra from grad school.

 

So what you are saying is - there is a limit to how fast the pads should really close or atleast react to our imperfections.

When playing different electric guitars there are clear differences as to how fast one can play.
Some are very fast and respond quickly, one just has to put the finger on the string and the tone is there. Others requires that the string is pressed down to such depth that the response is noticably slower. When having played a fast one and picking up a slower one often means lots of slipped tones.
But going from a slow neck to a fast one is usually not a problem. One quickly gets used to the ability of playing fast.

(Sorry if I intruded in the analog discussion - did not mean to hijack this thread)

 

no trouble. it relates. the point is to find something interesting to talk about

(Sorry if I intruded in the analog discussion - did not mean to hijack this thread)