Compensate This!

ed packard · Post by **ed packard** » 17 May 2006 8:06 am

COMPENSATE THIS! Another long rant about things that you didn’t want to hear.

Let’s try to get a definition of a compensator, as referenced to PSGs: How about… anything that “compensates” for any kind of “off pitch” problem, actual or perceived.

There are a variety of things that cause off pitch problems, given in no particular order.

1. Misadjusted mechanisms.
2. Faulty mechanics, as fabricated, or from wear.
3. Unfortunate mechanical design practices.
4. The player.
5. Thermal issues.

Simplicity pleads for itself! Complex mechanisms lead to complex problems. Keep the design as simple as possible. If it causes more problems than it solves, don’t use it.

Most PSG problems are caused by folk that have a tendency to tweak things…I took the knurled knobs off the tuner mechanism on the BEAST because folk wanted to “feel the fit”. Return springs and stops are other invitations to disaster.

Poorly finished/maintained axles are another off pitch problem source.

Taking the rattle out of changer rods by removing the clearance is a problem.

Well, I suppose one has to learn somewhere. The above are things that “people” have control of, but there are other “off pitch” things that one just has to learn to live with.

1. On some tunings/setups there is as much as a 10 to 1 difference in the amount of “String Stretch” required for a halftone pitch change. Why is this worth considering? Because the pitch shift for equal downward pressure on the strings shifts each strings’ pitch a different amount…noodlers and Gatling gun players won’t care as much as the full chord players. The ear can servo in on two strings via pressure differential and slight slants, but not three or more strings.
2. With temperature change due to hand and environment, each string will change pitch by a different number of cents, and at a different rate of change and return.
3. With temperature change, the body, and mechanisms will change length by an amount dependent upon the materials used. The nut to bridge distance will change accordingly; and so will the pitch of each string…by a different amount. Studio work with controlled temperature (environment) will require less tweaking of tuning than flat beds in a supermarket parking lot.
4. For the JI (in one of it’s many practiced forms) folk; If you tweak in the sound you like on open strings re the open string Root tuning, and the basic changes that you use (via compensation or ?), and then use a III chord structure (for a simple example) something is going to be “off”. If you have a “compensator(s)” to correct the III chord, what will you do if the chord root is a bII, II, bIII, IV, bVII, VII etc…that is a pot full of compensations. The alternative seems to be play only a few simple chord structures, or don’t play the myriad of chords available (see the thread on JAZZ CHORDS for illustrations in the extreme). Some playing styles are better for living with these problems than others.

Why is the PSG more of a problem than a piano that has many more strings? Because the piano strings are length and gauge matched to the frame material/shape and the PSG is not. I like a piano…you don’t have to change the strings every couple of sets…electronic/software ones are even better.

Electronic pitch compensation re (ET/some forms of JI) on the fly, and per chord structure exists on a few instruments…I forget the name of the process at the moment. AS the PSG progresses into the Electronic pitch shift age, the mechanical compensators will pass away like the dinosaurs…for now, whatever turns your crank.

Ray Minich · Post by **Ray Minich** » 17 May 2006 8:11 am

Ed, for me it's No. 4. Until I get that repaired...

ed packard · Post by **ed packard** » 17 May 2006 8:30 am

Ray...mine also...I just can't seem to fix me, so no sense trying to fix instrument..PF would not believe how bad his instrument could sound if he heard me play (word used loosely) on it!

Curt Langston · Post by **Curt Langston** » 17 May 2006 8:37 am

<BLOCKQUOTE>quote:<HR>3. Unfortunate mechanical design practices.
<HR></BLOCKQUOTE>

ED,
That is the one that seems to be a controversial one.(could long keyheads be a cause)

BTW Ed, does Sierra offer compensators? I did not see them on their website.

Thanks for the info.

ed packard · Post by **ed packard** » 17 May 2006 9:01 am

Curt...Re Sierra & compensators...ask Tom. If you want to call the correction(s) for raising a string a halftone, and activating a second change at the same time to lower it a halftone a compensator, then yes. Beyond that, I have had no reason to ask.

Re keyheads & design deficiencies...that could start world war three! The Fender type (Strat/Tele) keyhead layout is the best for thermal pitch change compensation, but only in the right direction, not magnitude.

Frank Parish · Post by **Frank Parish** » 17 May 2006 9:22 am

Carter Steel Guitars..problem solved!

Curt Langston · Post by **Curt Langston** » 17 May 2006 9:23 am

ED,

Re keyheads & design deficiencies...that could start world war three!

Well, we would not have to mention any names!

I guess my question to you is: Is there a relationship(correlation) between the length of the keyhead anchor from the nut, and the need for compensators? For instance, would a longer keyhead theoretically have a increased need for compensators?

Since you have done extensive studies, I thought that you are the appropriate person to ask.

Thanks again for your insight.[This message was edited by Curt Langston on 17 May 2006 at 10:51 AM.]

Curt Langston · Post by **Curt Langston** » 17 May 2006 5:50 pm

ED? You there?

ed packard · Post by **ed packard** » 17 May 2006 6:24 pm

Curt...I have not done much on the compensator issue except re using a correction for raising and lowering a given string at the same time.

My reason for ignoring it is mostly because my 13 series tuning structure allows(requires) that each and every string is used as the root of a chord. If I tweak the third for that chord, then it is out when it becomes the root of another chord, and so on for 14 strings. I have a choice and I choose simplicity...tune straight up and live with the results.

There are other possible sources of not returning to pitch than string overhang length. A perfect roller nut would solve the extra stretch problem for the long strings...all roller nuts are not created equal, so variations between instruments might be expected.

My personal preference is for the short overhang (associated with the keyless/gearless approach)...and the shallow angle for strings beyond the nut and bridge.

Someone might want to use a string lock on their keyed unit to verify if the nut friction, or the hangover is the cause of the pitch hysteresis (glad that the word is finally getting spelled correctly). There is a lot of mechanism in the pull path for the string that could be the source of the hysteresis. Since there are differences in the changer designs, one instrument with the same overhang might not behave like another.