Would someone define "hysteresis?"

Stephen Gambrell · From: Over there

I have seen the term "hysteresis" used on this Forum ever since I became a member. Could someone PLEASE define it for me? And PLEASE, NOT in terms of "Keyed vs. Keyless," JI vs. ET," or any "example" type definitions. I want to know what the book says, and how the term came to be associated with this thing sitting in my music room.
Thank you very much.

Joey Ace · From: Hamilton, Ontario, Canada

The string does not return to the proper pitch, due to mechnical issues.

Peter · Posted 19 May 2006 6:12 am

Webster:
Hysteresis represent the history dependence of physical systems. If you push on something, it will yield: when you release, does it spring back completely? If it doesn't, it is exhibiting hysteresis, in some broad sense.
The term is most commonly applied, as Webster implies, to magnetic materials: as the external field with the signal from the microphone is turned off, the little magnetic domains in the tape don't return to their original configuration (by design, otherwise your record of the music would disappear!)
Hysteresis happens in lots of other systems: if you place a large force on your fork while cutting a tough piece of meat, it doesn't always return to its original shape: the shape of the fork depends on its history.

[This message was edited by Peter on 19 May 2006 at 07:14 AM.]

Ray Minich · From: Bradford, Pa. Frozen Tundra

Hysteresis: When entropy wins...

Charlie McDonald · From: out of the blue

What happens with my wife when I am looking at pedal steels.

ed packard · From: Show Low AZ

Charlie...you are NUTS!

Marlin Smoot · From: Kansas

Can't imagine what happens with Charlie's wife if Charlie actually BUYS a steel...

James Morehead · From: Prague, Oklahoma, USA - R.I.P.

That's easy, Marlin, Charlie doesn't return home in his original shape!

And he may be HISTORY! (Please forgive me, couldn't resist, Charlie!)

[This message was edited by James Morehead on 19 May 2006 at 08:54 AM.]

Bob Knetzger · From: Kirkland, WA USA

My EE buddy explained hysteresis to me as simply "persistence and delay"-- what ever change you make to a system, it takes a little bit of time to have the effect begin.. and it continues on by itself a little bit longer, too. Using that definition applied to pedal steel mechanics it could be something like sloppy pedal action--too much slack in the linkage and/or gummy changer with slowed pitch return. Or more subtly, the physics of a string resisting being streched to new tension/pitch..and then taking time to recover back to pitch when released.

Since music happens over time, hysteresis is an interesting concept to think about.

An Ebow has this--slow attack and a long fade out (hey, and it's magnetic, too!)

What would "sonic hysteresis" be? Maybe a repeating slap back echo. You don't hear it right away..and then it slowly tails off.

What would "musical hysteresis" be? Maybe a steel part that stays on the "old chord" a little longer, then finally resolves a little later to create a musical "tension and release" effect. ..like going from a I to a V chord and but holding the tonic note over the V (becoming a sus4), then lowering a half step to be the 3rd of V...a delayed A pedal release.

ed packard · From: Show Low AZ

Since folk are using "hysteresis" to describe
returning sharp after being flatted and released, perhaps "overshoot" would be a better term.

Hysteresis in magnetics and materials is used to describe something that does not return all the way after being displaced.

Jim Sliff · From: Lawndale California, USA

Well, all thedefinitions pretty well sumup what I've said in a couple other threads.

It means something is mechanically unsound. Ergo, compensators to overcome it are correcting an engineering defect.

Brint Hannay · From: Maryland, USA

My Webster's defines "hysteresis" as follows: "a retardation of an effect when the forces acting upon a body are changed (as if from viscosity or internal friction)". Somehow I doubt that definition will resolve this debate.

Brint Hannay · From: Maryland, USA

Jim, I think what many of those responding to your posts are saying is that your claim that the mechanics of an instrument that suffers "hysteresis" are faulty is like saying that someone's machine failing to achieve perpetual motion is because it's badly designed. Some things simply aren't possible!

Tucker Jackson · From: Portland, Oregon, USA

"It means something is mechanically unsound. Ergo, compensators to overcome it are correcting an engineering defect."

Well, yes. Of course. You'll notice that not too many are arguing that point with regard to hysteresis.

But then, this is a problem that over 90% of existing guitars exhibit to some degree. So what are we going to do about it? Throw out all the keyed guitars? Some would say 'yes!,' but a few folks are attached to their Fenders and Emmons and Carters and Fessendens and Sho-Buds...

And getting the guitar "properly setup" will only have limited affect on this kind of design flaw.

Hence, one of the (many) reasons some people use compensators. Yes, it corrects a design flaw. Yes, that flaw is systemic across brands and not just a "few bad apples." Yes, compensators work. No, they're not just marketing. Yes, there is no Santa Claus. Yes, without a compensator you can probably register hysteresis of your E-string on a tuner. Yes, you should check your guitar, just for fun. Yes, you can ignore the issue if your ears can't detect it. Yes, you can (and should... at all times) fudge the bar to play in tune, regardless of your tuning method or design flaws inherent in your guitar.

Yes, I'm sure I've left something out and will think of it later

[This message was edited by Tucker Jackson on 19 May 2006 at 10:39 AM.]

Curt Langston · Posted 19 May 2006 9:37 am

quote:
Some things simply aren't possible!

But hysteresis originating from the key head, is totally preventable. As witnessed by Sierra and GFI keyless guitars.

A keyed guitar will have hysteresis by design.

Curt Langston · Posted 19 May 2006 9:38 am

Good one Tucker!

Bobby Lee · From: Cloverdale, California, USA

Great summary, Tucker. Thanks.

Tony Prior · From: Charlotte NC

and of course the KEY vs KEYLESS thing entered the scenario as a factual issue.

Even though the thread originator asked to leave that equation/OPINION out..

and of course a string cannot cause such a severe issue, only the multiple thousand dollar guitar..

definition:
__________________________________________

Hysteresis phenomena occur in magnetic and ferromagnetic materials, as well as in the elastic and electromagnetic behavior of materials, in which a lag occurs between the application and the removal of a force or field and its subsequent effect. Electric hysteresis occurs when applying a varying electric field, and elastic hysteresis occurs in response to a varying force. The term "hysteresis" is sometimes used in other fields, such as economics or biology. In such cases it describes a memory or lagging effect in which the order of previous events can influence the order of subsequent events.

_____________________________________________

It says nothing about an engineered device being poorly designed...

I hope that nobody is suggesting that many Master Builders don't know what they are doing...as is assumed by mentioning the numerous brands...

Because that is what I take away from all of this...

lets just completely overlook that a well designed Steel, with even the most precision components, is dependent on a 50 cent string, and that each 50 cent string forever is perfectly matched to the last 50 cent string that perhaps..uhh..broke..

[This message was edited by Tony Prior on 19 May 2006 at 11:56 AM.]

Brint Hannay · From: Maryland, USA

I agree, nice summary, Tucker!
I'm sorry to get involved in letting the keyed vs. keyless topic rear its head in this thread, but Curt, I have a GFI keyless, and I love it!!!
BUT IT HAS HYSTERESIS!!! It's a fact!!!

Curt Langston · Posted 19 May 2006 11:23 am

Sorry Tony. I could not help myself, being how the vast majority of hysteresis cause is keyhead.

Brint: Your hysteresis is most likely happening at the changer. Not the keyless. As you know, your GFI has no roller nut. There is virtually NO string behind it. Come on, how can it be the head?
I'd look really close into the changer, because it is not the keyless design. If you don't see a problem, have the guys at GFI look at it. I have had two keyless GFI's. NO hysteresis on either. In fact, until just now, never heard of a GFI to have keyless hysteresis.

You may have other issues going on.

Lee Baucum · From: McAllen, Texas (Extreme South) The Final Frontier

I played an Emmons push/pull guitar for many years. It had the typical hysteresis problem on the E strings. Raise the E's a half-step and they returned a hair flat. Lower the E's a half-step and they returned a hair sharp. Simply picking the string again or bumping one of those knee-levers made the string snap back to its original tuning. I got in the habit of bumping the lower lever after using the raise lever and bumping the raise lever after using the lower lever. That seemed to do the trick. I didn't even have to think about it. They were both on the same knee. Whenever I would release the lever, I would bump the one on the other side.

I have noticed that my Mullen does not have this problem with the E strings. They always snap back to E (according to my tuners) after raising or lowering them. I don't know if this applies to all Mullen guitars. Perhaps I just got lucky.

------------------
Lee, from South Texas
Down On The Rio Grande

Mullen U-12, Excel 8-string Frypan, Evans FET-500, Fender Steel King

Franklin · Posted 19 May 2006 1:40 pm

Tucker,
That's a great paragraph.
Here's my summation of all the threads pertaining to this issue.

So far Curt admitted in the keyhead vs keyless thread to having "ALMOST" no return hysteresis. "Almost" does not equal "Zero".

In the same thread Ed verifies that although the beast has some return hysteresis he doesn't need compensators because of his open tuning.

When I remove all of the posts speculating a cause trying to fix blame on a certain component of a guitar over another part of its mechanics on this return hysteresis subject, of which for the past 40 years has been through intensive studies ending in the same unresolved conclusion by virtually every great builder in the industry, We end up with a poll of who has it vs who has never noticed it.

These are the poll results.

Counting Tucker, Fred Layman, Bobby Lee, Ed and Curt so far there are five keyless owners of various brands on record confirming their personal keyless guitars do experience the scenario of return hysteresis, either alot or a little. And I and numerous others can varify the keyed side experiences the same return hysteresis, either alot or a little within all brands.

Only Eric & Jim stands alone believing return Hysteresis is smoke and mirrors and probably doesn't exist. I believe Jim plays an 8 string Fender. Not sure what Eric plays.

The thread also mentions that a "Tunable Return Compensator" completely eliminates the return hysteresis and so far with hundreds of posts on the subject nobody has said they don't work and I will verify they have worked perfectly on my Emmons, MSA, Sho Bud, and Franklin guitars.

Its interesting that Although some do advocate no need for them, No one has said they tried them and they don't completely work to resolve the problem.

Those that advocate no need probably don't hear it and are completely comfortable slanting the bar a little to compensate for this type of hysteresis.

There are various tuning issues that can be resolved with smooth rotating rollernuts and a virtually non-flexing changer. But return hysteresis is not one of them.

Blaming return hysteresis on a faulty mechanical design is like using a soft foam hammer to drive a nail into a piece of Oak.

Paul

[This message was edited by Franklin on 19 May 2006 at 02:48 PM.]

Charlie McDonald · From: out of the blue

Ed said:

ed packard · From: Show Low AZ

By measurement(s) using the Peterson, the BEAST "over returns" by less than a cent in both directions (E string)...it is so little that I can't get a measurement on it. It does not change with fast or slow raising and lowering, or rough or gentle activations and releases.

For History, I believe that Carl Dixon was the first to use the word hysteresis on the Forum to describe this effect. He spelled it hysterisis. When questioned about the word he responded somthing about 'as long as we know what we mean'. Hysteresis would be NOT returning to pitch as opposed to overshooting...but "as long as we know what we mean".

Bobby Lee · From: Cloverdale, California, USA

The word is misused by steel guitarists, I know. I'm not sure who started it, but it was part of our vernacular long before the Forum arrived. I'm tempted to blame Tom Bradshaw.

Let's all call it "over-return" from now on. Whad'ya think?

------------------

Bobby Lee (a.k.a. b0b) - email: quasar@b0b.com - gigs - CDs, Open Hearts
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