Cabinet drop

Charlie McDonald · Post by **Charlie McDonald** » 18 Jan 2006 8:05 am

I asked a question about cabinet drop with respect to string guage. John Fabian answered:

The larger the core wire (think of an unwound string as a core wire for a wound string), the more noticeable the effects of cabinet drop. The reason is that the amount of movement required to raise or lower a string is inversely proportional to the diameter of the core wire.

In my case, the offending string is B5--.0020.
Assuming the actual cause is indeed cabinet deflection and not linkage deflection: I am wondering if overstringing (increased guages in the treble) would apply more static tension in the system, thereby reducing the amount of drop in pitch on an individual string.

Otherwise, logic might suggest understringing those guages, if I follow John's argument correctly.

Any thoughts?

David Doggett · Post by **David Doggett** » 18 Jan 2006 8:24 am

Well yes, with a heavier guage string there is more static tension, but it also takes more force to raise the string. So I'm not sure you will come out ahead.

Bobby Boggs · Post by **Bobby Boggs** » 18 Jan 2006 8:36 am

The more tension you add the more cabinet drop you're going to have.Lighter gauge strings, all 10 or 12 might help a little.Or try this. Tune your 4th string to pitch.Back all the others off several rounds.See if you don't have less cabinet drop? You can't play it that way. But you should have less cabinet drop.

[This message was edited by Bobby Boggs on 18 January 2006 at 08:41 AM.]

Bobbe Seymour · Post by **Bobbe Seymour** » 18 Jan 2006 8:57 am

or----------->, you can go to a wound 20 or 22, re adjust the guitar for this change and the string will sound better and your "drop problem" will be gone forever.
At the expense of slightly higher "B" pedal pressure. Older Sho-Buds should all do this, ala Lloyd Green himself.

Bobbe,

Bobbe Seymour · Post by **Bobbe Seymour** » 18 Jan 2006 9:14 am

I hope most of you guys know that the dreaded "Cabinet Drop" problem is not the Cabinet actually dropping or bending but rather a series of other flexable things going on with the guitar.
The new "Magnum" has almost NO problems in this area, the problem is taken care of where it really is, and not in the Cabinet.
Some of the old Sho-Bud Super Pros were pretty bad, but who cares, no one can tell when you are playing with the band. I've never seen a tele player or a singer that was more in tune than a "Cabinet dropping" steel anyway! So why are we bothering to worry about this problem? Is your bar placment that accurate? Don't you use any vibrato? If you are haveing a problem, I'd like to hear you play perfectly in tune with a band and no vibrato.

Bobbe

[This message was edited by BobbeSeymour on 18 January 2006 at 09:17 AM.]

Jim West · Post by **Jim West** » 18 Jan 2006 9:18 am

I'm gonna start one here -

I don't believe there is such a thing as cabinet drop. I took my guitar (Fessenden S-12), put my hands on both the front of the guitar and the back at the midway point and applied a good 30-40 lbs. while someone else picked strings. The worst detuning I found was about 5 cents.

I don't know what causes detuning but after that I was sure it wasn't cabinet drop or deflection. I mean a pedal exerts what, about 5-8 pounds? And that's at the end of the guitar.

OK, let's here it!

ed packard · Post by **ed packard** » 18 Jan 2006 9:21 am

Charlie...try BB's experiment, but also note the amount of pitch change as you reduce the tension on the other strings. This was part of the BEAST design tests on the SIERRA session hardware, and reported on the Forum a couple of years back.

The neck on a 14 stringer may have as much as 400 pounds tension (approx). This tension tends to bend the neck like a bow. The strength of the body structure is the key to reduction of this flex effect.

The tension is applied to the body via the tuner/nut and changer to body mechanics. These stick up above the body by an inch or more providing leverage. If these are unstable (bend/flex) the result may be mistaken for "cabinet drop.

Set the pitch of the strings, then hang a weight on the body at the half scale point...remeasure the string pitch. To the degree that the pitch lowers, so is the susceptibility of the design to body flex/pitch drop.

Reducing either effect from a string standpoint is therefor a matter of minimizing pitch change per change in string length (as opposed to string tension).

If you have a keyless, you can use a fish scale to pull the string and see the pitch shift, and string stretch per pounds of pull.

Run the experiments, come to some conclusion for the instrument that you have, and pick your poison.

We have not addressed the way that the pedal/lever tension changes are applied to the body/strings (how the cross shafts get the force changes.

Glad that you did not go away...good discussion content.

John Daugherty · Post by **John Daugherty** » 18 Jan 2006 10:00 am

My advice: Don't get so wound up in mechanical issues that you forget this is a musical instrument. Steel guitars with cabinet drop have been thrilling the ears of music lovers for a long,long time. Let-ur-drop and get-ur-done.

------------------
www.phelpscountychoppers.com/steelguitar

Charlie McDonald · Post by **Charlie McDonald** » 18 Jan 2006 10:02 am

My thought exactly, David, a tradeoff.
However, I can stand more B pedal pressure with the crank/rod positions I have, and think a wound 20 or 22 may help.

The upshoot is I suspect other forces in play as do Jim, Bobbe, and Ed. I'll do some experimenting and let all know what I come up with.

A piano has some 10 tons of combined tension, but is backed up with massive structures, therefore no 'cabinet drop' when pedalling. Thus I imagine that the greater the combined tension on a steel, the less noticeable the deflection. But all possible recourses end up a guitar that is way too heavy to carry around.

ed packard · Post by **ed packard** » 18 Jan 2006 10:22 am

While you are at it Charlie, don't forget pitch change with temperature (think flatbeds in parking lots etc.)

What do you consider "too heavy"?

I will show you some flex and structure resonance calculations (computer models) in DALLAS...includes the 100 lb center load deflections et al.

Clyde Lane · Post by **Clyde Lane** » 18 Jan 2006 11:58 am

Charlie, I think I read in another thread that you lower the 6th to F#. Some guitars have a problem lowering a wound string G# to F#. You may have to drop the pull rod lower on the bell crank to get it. Some Sho-Buds will not do it at all.
Clyde Lane

Eric West · Post by **Eric West** » 18 Jan 2006 1:20 pm

I think it's got more to do with the main finger axle wobbling around than anything else. The whole string load might be 2-400 lbs but the single change of one pull is only a couple more pounds at most. If it changes things, I'd look for movement in the finger axle.

As for cabinet flex, I'd say that the foot pedals pulling down on the front apron is probably more of a "flex" factor than anything else. You're pulling against a dead stop, so it's not just the load of the string.

I have no measureable drop in my new Marrs, whereas my PIII was getting pretty bad. DM's steel angle plat across the inside of the front apron is a great idea.

I havent checked how loose the finger axle is on my PIII, but I'd bet it's looser than on my Marrs.

If it were I, I'd machine it larger so it'd have to be fairly driven through the changer to minimize any movememt.

EJL

Ron Sodos · Post by **Ron Sodos** » 18 Jan 2006 2:28 pm

I am confused. Are you really using a 20 for the 5th sting? I use a 17 and a 22 for the 6th string.

Charlie McDonald · Post by **Charlie McDonald** » 18 Jan 2006 3:14 pm

I was using a 20--I don't remember why--but tried a 17 to test my thinking. That would actually seem to fit John Fabian's equation.

The 20 wound worked well, reducing the amount of drop by half, to a Hz or so, nearing the threshold of noticeability.
But sure enough, Clyde, the wound string would not raise or lower enough, even changing the pull points.
Ah well, it's always something.
Thanks, all.

Dave White · Post by **Dave White** » 18 Jan 2006 3:41 pm

I thought cabinet drop was what happened if you weren't careful turning it upright after you put the legs and pedals on. Seriously, though, I think what Bobbe said at the end of his second post was right on.[This message was edited by Dave White on 18 January 2006 at 03:48 PM.]

Earnest Bovine · Post by **Earnest Bovine** » 18 Jan 2006 5:29 pm

Bobbe wrote <BLOCKQUOTE>quote:<HR> or----------->, you can go to a wound 20 or 22, re adjust the guitar for this change and the string will sound better and your "drop problem" will be gone forever.
At the expense of slightly higher "B" pedal pressure. <HR></BLOCKQUOTE>
Right, and the extra work that you have to put into that "B pedal" causes more drop on the other strings, especially the 5th string. Still, it (wound 6th )is worth doing IMO.

Willis Vanderberg · Post by **Willis Vanderberg** » 18 Jan 2006 6:15 pm

Or you can buy a Emmons LeGrande lll and forget it.Zero , zilch, nada, cab drop.
I do think the lighter guitars, for example, MCI have greater drop than others.
Even the best guitars usually have a bunch of compensators on them.I have seen as many as eight extra rods on some top pickers guitars to compensate .
But , having said this, I do agree that there is way too much attention given to this subject. If I had the worlds most perfect steel you couldn't tell by my playing. And if I was a great picker the rest of the band isn't in tune anyway..LOL[This message was edited by Willis Vanderberg on 18 January 2006 at 06:16 PM.]

Duane Reese · Post by **Duane Reese** » 18 Jan 2006 7:15 pm

I've never really had any noticeble cabinet drop; you can see it on a really good tuner but not more than a couple of cents, and I play big old Sho-Buds and Emmons - you know, the kind that growl and snarl at you when you first sit down...

Why this one day, my push-pull just up and bit my leg for no reason! I had to throw it against the wall... Banged it up real bad but it hasn't acted up since, so...

Bobby Boggs · Post by **Bobby Boggs** » 18 Jan 2006 7:50 pm

<BLOCKQUOTE>quote:<HR>I do think the lighter guitars have greater drop than others.
<HR></BLOCKQUOTE>

That's been my experience........bb

Frank Parish · Post by **Frank Parish** » 19 Jan 2006 4:46 am

I'm playing a Carter D-10 right now and there's no more cabinet drop on this guitar than any I've played. It's the same as 98 model Legrande II I had, no difference.The Carter has the metal plate behind the front apron too. I had an old Sho-Bud Pro II that had zero drop and I always figured it was just a big piece of wood that wouldn't bow. I had a Derby that had the very most cabinet drop of any of my guitars. The Emmons p/p's I have now are next to nothing. I can tune the E's without pedals down and play it.

Charlie McDonald · Post by **Charlie McDonald** » 19 Jan 2006 5:32 am

Right, and the extra work that you have to put into that "B pedal" causes more drop on the other strings, especially the 5th string.

That's where I arrived at the end of the day yesterday--today I'm restoring string guages and let the drop fall where it may.
Nights, I dream of a new guitar. They've changed since the early 70's MSA.

John D. has a good point. The more I mess with it, the more it becomes a machine and less an instrument.
On the other hand, maybe that's what interests me most. More later.

ed packard · Post by **ed packard** » 19 Jan 2006 7:48 am

What is next Charlie?
OK...the body flexes when the string tension is added, and flexes a bit more if a weight is attached to the midsection. The amount of effect that the flexing has upon the pitch of any given string can be measured in cents, or in Hz with a good tuner(I use the Peterson).

My simple test for added weight is to use a 30 pound weight from a weigh/excersise set suspended with a guitar strap to the center on the scale.

My simple test for reduced tension is to detune (slack) each string (except the reference string) one at a time, and an octave at a time, and record the number of cents change in the reference string.

The change induced by pushing pedals/levers can be quantified in the same way. Realize that the pedals/levers, and the slacking of string test introduce the changer into the equation; plus pressure at other points in the instrument, such as at the stops (pedals and levers per E. West), and the screws/bolts for attaching the changer.

How much pitch change is tolerable? If all strings shifted the same amount, and in the same direction by a few cents, fewer folk would care. The difference obtained by bar placement and motion would exceed the mechanism faults.

My personal feeling is that if we draw the line of acceptability at about 5 cents for pedal action or center load, most pickers would live well with that. Why 5 cents? Set an unwound string to pitch...then just rub your fingertips lightly up and down the string and watch the cents drop. Pick the string hard, and watch the cents drop as the vibration decays. Cheaper tuners tend not to show this effect.

Not returning to pitch, would be to me, a more annoying problem...this is usually because of a mechanism (as opposed to body flex) issue.

How about data on 32 PSGs, ranging in age from 30+ years to made last year as a reference? Ask Jim Palenscar.

Lee Baucum · Post by **Lee Baucum** » 19 Jan 2006 8:50 am

Cheaper tuners tend not to show this effect.

Aha! Yet another reason to purchase a cheap tuner! If your eyes are telling you something that your ears don't perceive, get the cheap tuner, tune your guitar, and play it.

I agree. 5 cents should be acceptable.

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

Mullen U-12, Evans FET-500, Fender Steel King

Charlie McDonald · Post by **Charlie McDonald** » 19 Jan 2006 10:05 am

How much pitch change is tolerable?

However much you end up with.

Bobbe's right; a wound twenty cures cabinet drop. And every other raise and lower you might need on that string.

I really like the sound of wound strings.
I could have one on G#, or I can have a lower to F#, but not both.

If you undertake to make a lot of guage changes, and you don't map your rods, it will take you a lot longer to find your way back. Duh.

I'm back to standard guages. Something tells me it's been worked out before.

Conclusion: what's a little cabinet drop between friends?
I'll just do what David Doggett does, split the difference on that string, between pedals up and pedals down.
Most interesting discussion.

John Fabian · Post by **John Fabian** » 19 Jan 2006 10:08 am

Charlie,

A 17 would cause the mechanism to operate improperly if used for tha 6th string G#.

The core wire for a 20 WOUND would be around 10 - 11 and would handle most of your audible problems.[This message was edited by John Fabian on 19 January 2006 at 10:08 AM.]