Does cabinet drop exist or not?

Charlie McDonald · From: out of the blue

I don't see that it's a negligible problem, if there are manufacturers that are trying to beat it. It may not be a 'real world' issue, if you're playing in bands; but it's physics and can be worked with.
I think somebody's going to do a complete stress study and find out what it is.

In the meantime, I think a bottom cover plate made of sheetmetal would be a good start, affixed before the guitar is strung.

Bobby Lee · From: Cloverdale, California, USA

I think of it as "re-tuning" rather than "de-tuning". The tuning of the guitar changes when you press the pedals. That's what a pedal steel does. Duh!

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Bobby Lee (a.k.a. b0b) - email: quasar@b0b.com - gigs - CDs, Open Hearts
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John Drury · From: Gallatin, Tn USA

Cabinet drop can also be an intermittent problem. When I worked at SGN, Bobbe had a steel on the floor for a few months that would drop like crazy. I had to listen to that P.O.S. for hours on end while random pickers would come in and play it.

At one point I truly wanted to take an axe to the sombitch. It was an old Z-B Custom, single coils to die for! The rest of it belonged in the dumpster!

One day Seymour sat down and flogged it for a few minutes and the problem went away.

It happened a week later when Tommy White came in and played it, the drop disappeared!
Lloyd green came in one saturday and it behaved for him too!

Right after he left I threw a tuner on that fugitive from a chip mill and Wham! The cabinet drop was back! Go figure!

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John Drury
NTSGA #3

Pat Kelly · From: Wentworthville, New South Wales, Australia

John, I think you have quite elegantly said it all.

[This message was edited by Pat Kelly on 29 January 2006 at 01:33 AM.]

Bill Hankey · From: Pittsfield, MA, USA

John,

A downward pressure of the bar exerted by the great players you've named, could account for how this happened. The subtle abilities of Green, White, and Seymour, to detect something amiss, would require about 39 seconds. It would then be possible to select melodies which would allow them to circumvent the problem area. It's doubtful that a broken string or
minor detuning would stall their performances. Playing on the right of a fret, bar pressure, and left finger pulls, all of which influence the proper intonation.
The quickness of the hands, helps to explain how all three s.g. accomplish unbelievable feats. To prove the point, hold the thumb with the index finger. As the thumb is released under pressure, it springs away to a new position. It is impossible to see as it moves to an outward position.

Bill

John Drury · From: Gallatin, Tn USA

Bill,

My post was in jest, I knew exactly what they were doing and yes they do it in such a way that is almost undetectable. It doesn't take them any 39 seconds either, if the drop is present or the intonation is off these cats have ears that pick it up in a New York nanosecond and they correct for it immediately.

Some of the prettiest playing I have ever heard was by Bobbe Seymour on a wore out ashtray Maverick that I wouldn't wish on anyone.

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John Drury
NTSGA #3

Bill Hankey · From: Pittsfield, MA, USA

John,

Two trite expressions, " What you see is what you get", and "Seeing is believing", perhaps should be written; it's what we don't see, that really matters more.

Bill

Bob Hoffnar · From: Austin, Tx

Every guitar I have owned has cabinet drop. Playing in tune is mostly another issue though, for me at least.

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Bob
upcoming gigs
My Website

[This message was edited by Bob Hoffnar on 29 January 2006 at 08:14 AM.]

Bobby Boggs · From: Upstate SC.

b0b wrote:

Tom Quinn · Posted 29 Jan 2006 12:20 pm

In the early 70s, there was one guy in the Steel World selling items who went ballistic about cabinet drop. He just ran on and on about two of the then-popular guitars having dreaded cabinet drop, how poorly made they were and that they caused cancer and emrods in yer secret places... -L-

He really put them down. There was a new brand on the market he LOVED, cause there was no "cabinet drop." Of course, the new guitar sounded terrible, compared to the older "inferior" ones, and that company eventually went under.

I think so-called cabinet drop is a red herring. Same as guys getting special bridges for their Martin acoustics, and etc. It is such an unimportant issue, compared to the actual ability to play the instrument, but YMMV and no problem...

Charlie McDonald · From: out of the blue

Robert Thomas · From: Mehama, Oregon, USA

What is cabinet drop? If you think you have it then switch to a HWP Mullen, beautifully made by Del Mullen. Maybe I am deaf, but it has never been a problem for me on such a fine, well constructed, quality instrument. I have been playing it for 6 and 1/2 years now and prior to that a 1970 Sho-bud D-10 for 27 years, I wouldn't go back for anything. Buy the best and you wont have a problem.

Kevin Hatton · From: Buffalo, N.Y.

Robert, after 6 1/2 years of playing you may be shocked to learn that even your beloved Mullen has drop on the sixth string when you press the A pedal.

Bobby Lee · From: Cloverdale, California, USA

I tune my A pedal to the 6th string. If they're both out by the same amount, what's the problem?

Like I said, it's not de-tuning - it's re-tuning.

Kevin Hatton · From: Buffalo, N.Y.

Thats the point Bobby. You tune a steel guitar to itself. It took me alot of years to realize that. Mostly from this forum.

Frank Parish · From: Nashville,Tn. USA

Like most folks here I tune my guitar to itself and it's in what I call A-440 with pedals down. It sounds better to me like this than any of the other methods I've tried. I don't really consider it a big deal unless it has substantial drop when I press the A and B pedals. I've only had one guitar with that kind of drop and I no longer have it. It was noticable when you pressed the pedals down to anyone that had a few years under their belt playing pedal steel.

Robert Thomas · From: Mehama, Oregon, USA

Hi Kevin, I have been playing psg for only 36 years, and about 23 years on non-pedal prior to pedals. I just got up from the computor and hooked up my tuner and did as you said I should do with the 6th string and the A pedal, and guess what, no cabinet drop. If I were to have done that with the Sho-bud Professional I don't doubt that it would have had cabinet drop, but some PSG'S are made a lot better today. By the way I tune 440 straight and always have, no problem with instrument or any of the groups I ever played with. Isn't this fun?

Kevin Hatton · From: Buffalo, N.Y.

Thats interesting Robert. I owned two Mullens and both had cabinet drop on the sixth string. I've never seen a steel guitar without it except for a Legrande III with the force eliminator. Frank, thats exactly how I tune.

ed packard · From: Show Low AZ

WARNING…this post is long, plus contains terminology and concepts that may have an adverse effect upon your established concepts.

First off, as you may have noticed from my pervious rants on the subject, I don’t like the term “cabinet drop” for the simple reason that it is not all that goes on re the problem of detuning/”retuning” to which it is used to refer. The body/cabinet is only one part of the equation. The mechanism(s) each contribute their own character to the detune/retune issue.

I had planned to do a show and tell re separating these elements at the SWSG convention at MESA, but the SIERRA table was at the corner of the bandstand and that would have been a distracting thing to do re the show.

STRING TENSION:
RE string tension…for the sake of easy discussion, we will use the value of 30 pounds pull (tension) per string, regardless of gauge and scale or string length. Different gauges = different tensions for a given neck length and note; different scale lengths = different tensions; different notes give different tensions. Different tensions add up to different amounts to body flex for the static tuning.

Calculations (simplified) for string tensions on various scale lengths, gauges, and activated changes yield values per string of somewhere between 26 and 33 pounds. Worst case full tone raises are in the range of +3 pounds of the non raised string tension; so the activated change per string raised is in the order of ten percent of the static string load.

Some folks use more changes per pedal/lever, so their tension change per activated change will be greater than for those using fewer changes…greater tension changes = greater amounts of “detune/retune”; the point is that those with a single halftone change on a “stiff” instrument with “solid” mechanics, and an insensitive tuner may recognize no detune/retune effect, while the heavily loaded changer folk will.

BODY FLEX:
If we take a ten string E9 at 30 pounds per string, we get about 300 pounds of tension. We won’t quibble about the keyless vs. keyed tuner string length differences here except to say that the longer string lengths, and body length of the keyed instrument just make the body flex numbers greater for a given body type. Take a 24.250 scale length and add the nut to tuner distance (worst case = 7”) and we have 31” of body and string as opposed to maybe 26” inches of body and string to deal with…a substantial increase.

The amount of “body flex” for a 300 pound load will be a function of body length, body thickness, body material stiffness (neck block included), skirt(s) length/thickness/depth material, and how they are attached to the top plate. Applying our assumed (convenient) value of 30 Pounds per non activated string, and we see that each string is about 10 percent of the static neck tension, and the a single full tone raise is about 1 percent of the full 10 string neck tension…you can be more accurate re your instruments dims’,
strings, etc. as you see fit.

In my case (the BEAST), I have a 30” scale, and a 31.5” string length on a 35” body with 14 strings (400 pounds plus). The top plate and front skirt are an aluminum extrusion…the back skirt is an aluminum plate, and the end plates are also aluminum, but thicker than the skirts and top plate; there is no neck block.

THE MECHANISM:
The height of the nut and the changer above the body also get into the equation. The value for my BEAST is 1.5”…The Sho-Bud pro is also 1.5”.

The way that the changer is anchored to the body is another high impact component. Because the pull on the string(s) is from the pedal/lever thru the changer to the string(s) the changer is being “twisted” by the activation tension…the tendency is to shorten the distance between the nut and the bridge (shorten scale length)…again, changed total load, number of strings, and halftones changed will give different folk different detune/retune results.

Changers are far from being all the same in materials and construction, so it should be no great surprise that they may not give the same results for different dynamic (activated changes) loads.

Cross shafts that are long and thin, and/or made of a material the will flex/twist when loaded add another dimension to the picture, particularly when heavily center loaded by the changes.

Stops are a real source of irritation. The heavy footed pedal mashers have been known to cause certain types of stops to bend/break…I would suspect that they would also have had spent a lot of time trying to keep the instrument in tune.

Where the stop is located will effect the detune/retune issue because they can transfer the full foot pressure to the body/mechanism complex. If a stop applies the foot force directly to the front skirt in a downward direction, it will be different from one that applies the force to a metal rib attached to the inner section of the body. An inner rib(s) will also stiffen the body and further reduce the amount of body flex. It works like added skirts.

If a stop tends to apply the foot/pedal pressure in a sideways direction, it will have a lesser effect on body flex than one that applies pressure only in a downward direction because some of the applied force is along the skirt, or rib (horizontal) as opposed to the across the skirt or rib (vertical). Stiffness is some exponent of those dimensions, one being about 4” vertical for a skirt, and 30 some inches for a skirt horizontal.

The pedal bar might bend a bit as the pedals are mashed, but the stop should make up for this by stopping the rod motion and that should leave the pedal bar as a non entity in the detune/retune problem.

NOT RETURNING TO PITCH:
One of the detune/retune issues is that of a string returning sharp or flat after being activated and deactivated. Assuming that there are no large frictional things going on in the mechanism(s), and that the other strings did not vary from the static tuning value, all that is left is that the string has reached its plastic limit. This is usually seen in the G# = .011” string…time to change it.

On the keyed instruments, it is often found on the center (longer) strings. One cause is that the nut rollers are sticking…another is that the string/roller contact point is dented by the winding on these wound strings or the winding is dented by the roller at the contact point.

I general, there has been a tendency on the Forum to call the non return to pitch anomaly HYSTERISIS (hysteresis). It will be because of either a permanent string stretch, or some sort of stiction/friction effect in the mechanism. If the effect seems to be greater with higher temperatures, check for clearance between the axle and the hole in the rollers, or at the changer fingers. Some makers don’t provide smooth axles or holes, hence friction problems.

SOME MEASUREMENTS TO MAKE:
To isolate body flex from mechanism issues, and to assign numbers to the problem, place a strap around the center of the body, tune your string(s) of choice, hang a weight ( I tend to use a 30 pound weight from a bar bell set = about 10 % of the string tension on a ten string), and measure the number of cents that the string(s) change.

To see what over aggressive pedal mashing might do, apply the same 30 pound weight to your pedal(s) of choice and check the amount of pitch shift.

To see the effect of string tension on the combination of body flex and mechanism instability, tune your favorite string(s), then slacken (all the way) the other strings (each string is about 10% of the neck load on a ten stringer) and note the amount of pitch shift on the reference string(S) as each string is slackened.

To separate the body flex from the mechanism anomaly for activated changes (almost), choose your reference strings, tune them precisely, and tune the string(s) that would be changed by the pedals/levers by the amount that they would be changes by the pedals/levers, then read the cents change in the reference string(s). Now retune and see how many cents shift the pedals/levers give you on the reference string(s).

If you want to see what THERMAL issue amounts to, tune the instrument in a 70 Deg f room (stabilized), then put it in the sunshine (back porch), note the ambient temperature, wait for a while, and measure the pitch shift amount. Did all strings change the same number of cents? Do you care?

I get about 3 cents change from hanging the 30 pound weight on the beast (no neck block and the screws taken out of the fret board rails. I get over 5 cents of shift for just running my finger tips along the string several times…it returns to pitch soon after I stop rubbing. The point is the hand(s) on the string(s) may give more thermally induced pitch shift than is obtained from body flex plus mechanism anomalies on a well designed instrument.

SOME RANDOM COMMENTS:
Skirts can tend to flex outward or inward when loaded. Some makers bridge the inner and outer skirts together to reduce this effect = a partial fix as the major change load is on the front skirt in most instruments, so the back skirt may go in either direction. The deflection of a plate varies as the cube of the length for an applied force in the linear part of the materials curve.

When dealing with wood bodies, modulus of elasticity (controls the amount of bending for a given load) is somewhat elusive, and is also related to grain direction and proximity. Once the skirts are well attached, most possible structural deficiencies are compensated for…strength (rigidness) is one issue, tone (timbre) is another problem.

The thermal coefficient of expansion (TCE), and the thermal mass are different for different materials. The strings are thin and have a high value of expansion re the body. They will expand faster (lose cents) than the body, the body will take longer to come to temperature. The body will expand less than the strings, hence less tension on the strings as the temperature increases.

For those with a sensitive tuner…pluck the string as hard as you would while playing, then pluck the string very gently (as if a long sustain in a slow waltz)…how many cents difference?

If you think that your “extra” pulls on a pedal or lever are causing a tuning/pitch shift problem, consider adding helper springs…ideally, one string should supply all the return tension needed when the activated change is released, so the tension of added change strings can be subtracted out with “helper” springs (I said “ ideally).

For the players that pick only one, two, or maybe three strings at a time, and use only basic chord positions… You probably won’t be bothered very much by the detune/retune issue unless you are playing open strings or open string harmonics (flageolets) because you hand pressure on the bar, the inaccuracy of bar placement, the heat from your hands and so forth will obviate all your open string tuning efforts.

For the players that are prone to using many string chords…if “tweak tune” re the root string on the I neck (E on E9), and then use another string as the root of your chord, how would you “tweak tune” your opens? On my 13th series tuning, any string is a root for a scalar harmony chord in the key scale….should I throw all that away just to have the old “lap steel” no changes “tuned” sound on the open strings?

For those that consider this type of post as a waste of time, remember that you are playing an instrument that gives you the benefit of generations of thinking by luthiers, carpenters, cabinet makers, machinists, et al. All the improvements have not been made yet. Some of us get more fun from reducing the problems in the instrument(both real and perceived) than playing Way To Survive over and over.

[This message was edited by ed packard on 30 January 2006 at 10:56 AM.]

Bill Hankey · From: Pittsfield, MA, USA

Ed,

I enjoyed reading your input, that is clearly indicative of your wide range of knowledge relating to the steel guitar. Do you think an arch counterforce beneath a steel guitar could greatly reduce the flexure of the structure? An exampling would be a post installed beneath the steel to allow the leverage at the center point of the steel. A small
turnbuckle would enable proper adjustment. There would be any number of methods to achieve the actuating of a counterforce. Each would require a direct holding force at either end of the instrument.

Bill

[This message was edited by Bill Hankey on 30 January 2006 at 03:51 PM.]

Donny Hinson · From: Glen Burnie, Md. U.S.A.

Robert Thomas · From: Mehama, Oregon, USA

Hi Kevin, was your Mullen a HWP Mullen? If it wasn't there is your answer to why no perceptible cabinet drop.

Frank Parish · From: Nashville,Tn. USA

Robert,
I had a 70 Sho-Bud Pro-II that didn't have any cabinet drop (sorry Ed) and a 12 string Mullen that did have cabinet drop. I attributed the lack of drop in the Sho-Bud to a well made body of heavy wood that wouldn't bow.

Charlie McDonald · From: out of the blue

ed packard · From: Show Low AZ

Bill: I am not sure that I dig the turnbuckle approach as a fix all. The reason is this: The body is (worst case)like a bow with a 300 to 600 pound pull (S10 or D10).The more it is bent, the more resistant it is to being bent further...and then it snaps. If the turnbuckle takes the bow out of it, then it is back to zero where any pull means a greater bowing per pound applied. It is probably "good" that the body is highly stressed, and that the resulting strain is allowed. Those familiar with the S curve will know that if we are around the corner (in the non linear region) then a further change in tension will have a lesser effect upon bowing than being in the linear region of the curve.

Donny: I don't see how the Titanium rods would affect the thermal issues. Rods are generally a bit slack, and the stops make up for any expansion/contraction vs. temperature...in any case, the thermal coefficient of expansion for Titanium is given as 8.5 inches per inch per deg C...S steel is given as 17.3...construction steel as 12, and aluminum as 24. The SS strings are probably close to 17 or 18. That is two times the Titanium's expansion rate, and three fourths the Aluminums expansion rate.

Woods ranges from 4 to 24, depending upon type, direction, and moisture content. Plywood is the 4, so one would expect "Die board" to be less. Die board is used as body material by several makers.

The Carbon Composites seem to be anywhere between 0.5 and 6.5. The real value is a function of the percent fibre content, and the nature of the bonding material (depends upon who mixed it and how).

The least variable, and best ratio match to the steel seems to be Aluminum.

Frank: what did I say re Sho Buds other than that I have a 70 (about) Professional? I am missing the meaning of your "sorry Ed" comment...straighten me out please.

Charlie: I get only 3 cents pitch shift on my G# = 0.011" for the applied 30 pound center of the neck load on the BEAST...I can live with that in about any temperament. As for the learning to play comment, I may never get around to it!

In general: The weakest link in the body chain is where the hole is that holds the changer. Most of the body width on an S10 is removed to create the hole. When the changer is cantilevered forward by string tension, the body will bend most near the edges of this hole. To the degree that the pedal/stop force is downward, the situation is further aggravated.

On the BEAST, I have the changer and tuner integrated as a single unit, and located at the players left. This puts the weakest body area behind all the pedal force application points. With the changer hole on the players right, all the pedal/lever forces are more directly seen by the weakest body area.

Afterthought: Consider what electronic pitch shift would do for these applied force problems.

[This message was edited by ed packard on 30 January 2006 at 04:00 PM.]

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