Acceptable" cabinet drop.

Charlie McDonald · Post by **Charlie McDonald** » 2 Jun 2005 5:42 am

As a piano tuner, I thought the PSG would be much easier to deal with; being mechanical of mind, I was sure I could handle it.

After messing with my MSA Red Baron--Larry Bell warned me, I know--and couldn't get that 6th string to keep from going flat no matter what I did. And now I know what cabinet drop. Fiberglas is great for cars, not good for steels. It should have been sold as a pedal fiberglas. Someday, I might try a real steel.

But cabinet drop in a piano is not cabinet drop. TONS of downforce, rearranged while tuning, creates an unstable situation on the flexible soundboard. (The better the piano, the more flexible the soundboard.) Only when the piano is tuned again and again, and then placed in a studio with controlled temp and humidity, does it reach stability. The cabinet is the most rigid structures among instruments; it doesn't drop, but the flexible soundboard does change shape as the forces are rearranged.

Bob Carlucci · Post by **Bob Carlucci** » 2 Jun 2005 6:42 am

Wow,this thread died and was given an honorable burial well over two years ago!,,Jeez, we drug the bones up out the grave... bob

John Daugherty · Post by **John Daugherty** » 2 Jun 2005 8:04 am

Now that it is resurrected, let me add an interesting comment. I was talking with Bud Carter,whom it seems, I have known for 100 years (maybe just 99). I have a great deal of respect for Bud and his knowledge. He said he wanted to see if cabinet drop could be eliminated. He mounted the workings of a pedal steel on a table made of heavy steel plate. I do not remember the exact thickness of the steel plate. I think it was about one inch or thicker. When the pedals were depressed, cabinet drop was still there. From this observation, I have to think that to eliminate cabinet drop, you would have to build the guitar from something that you wouldn't want to carry.
Donny Hinson expressed my feelings on the subject, exactly........JD[This message was edited by John Daugherty on 02 June 2005 at 09:15 AM.]

David Doggett · Post by **David Doggett** » 2 Jun 2005 8:19 am

Yes, this is a very interesting old thread. I can't help but add a few things we have discovered in recent threads on cabinet drop and ET/JI tuning that weren't mentioned here (doesn't mean they weren't aware of these things back then).

If you tune by ear (i.e., take your Es from a tuner and tune everything else by ear), then cabinet drop mostly only affects playing open at the nut. That is because you will tune the pedal and lever stops to the unpedaled strings. For example, you tune the Es on strings 4 and 8 of E9 to a meter (straight up 440). When you mash the A and B pedals the Es typically drop about 2 hz (8 cents). But by ear you tune the A and B pedal stops to match those dropped Es. So the intervals are correct, but the whole chord is 2 hz (8 cents) flat. Playing with the bar a good player's ears will automatically compensate for that (you can't see that small difference in the bar, but your ears can hear it), and you will be on pitch with the other instruments you are playing with. Only when using the A and B pedals with no bar (open at the nut) will you be noticeably flat to the other instruments. A similar thing happens with the E lower lever, which causes cabinet raise to take the other strings slightly sharp. By ear you will tune the E lower lever stop to the other strings. The whole chord will be slightly sharp at the 0 fret, but the intervals will sound good.

If you play a lot open at the nut, you can help the AB pedal drop by splitting the difference. In the above example of 2 hz (8 cents) drop, you can tune the Es 1 hz (4 cents) sharp. Then the A chord with the AB pedals will be only 1 hz (4 cents) flat. Generally less than 5 cents off is acceptable. Of course now the E lower chord will be even sharper, but since the A and B pedals are use more often, that might be acceptable.

If you tune everything straight up ET, cabinet drop causes more problems, even when using the bar. You tune your Es 440. You tune your A and B pedal stops 440. Now, in your A chord with the A and B pedals down, the 5ths (the Es) are 438 and the root and thirds are 440 (8 cents difference). So the whole chord is off, and not just at the nut, but everywhere your bar takes the chord. A JI straight major chord has intervals 1,3,5 that should be 440, 437, 440 (the 3rd is 12 cents flat of ET). Tuning by ear to JI your A chord with the above cabinet drop will be 438, 435, 438. The intervals are correct, but the whole chord is 2 hz (8 cents) flat at the nut. If you tune ET you will have 440, 440, 438. The 3rd is 12 cents sharp of JI, but is right on for ET. But the root and 5th disagree by 8 cents, and this is everywhere, not just at the nut. Many people find this a very bad sounding chord. The 3rds are off (as with all
ET chords) and the 5ths are off. In other words everything is off.

You could split the difference with an ET tuning. Tune the open strings to 441, and the A and B pedal stops to 439. Now your E chord will be 441, 441, 441, and your A chord will be 439, 439, 439. All the intervals are straight ET and you are within 1 hz (4 cents) of ET at the nut on either chord. Of course, all the 3rds sound 12 cents sharp to JI ears.

You can work your way through all the pedal, lever and open string combinations this way. It is very complicated, because different open strings drop different amounts (generally the largest unwound and largest wound strings drop or raise the most), and raises cause cabinet drop while lowers cause cabinet raise. In some cases JI helps cabinet drop better, and in some cases ET helps it better. For the most commonly used straight major and minor chords, tuning the pedal and lever stops by ear or JI to the open strings gives good sounding JI intervals, but the whole chord may be slightly sharp or flat of the fret marker. ET will have more intervals off (both from JI and straight ET), but the chords will be closer to the fret markers, and closer to ET at the nut. Choose your poison.

One interesting mechanical thing I have noticed is that mashing harder on the pedals (within reason) does not cause more cabinet drop. That is because the pedals are achored to the pedal board and the legs. It does not appear to be the pedal rods pulling down on the middle of the cabinet that causes the drop. A pedal lower will cause cabinet raise. And a lever raise will cause cabinet drop. Thus, it appears to all come from string tension being increased or decreased.
[This message was edited by David Doggett on 02 June 2005 at 10:01 AM.]

Bill Myers · Post by **Bill Myers** » 2 Jun 2005 9:00 am

This is an intresting topic as you have multiple issues that are being discussed here. First, the assumption is made that as you move up the neck with a steel bar, that as you change the length of the strings, that a string of .011 and .034 are going to raise in pitch exactly the same. Well guys the answer is that they won't. have you ever looked at a les paul of telecaster and notices that to properly intonate a guitar the lengths of the string s must be different. And this will vary depending on which octave you take a measurement. To make the strings all intonate propely they would have to change lengths, but this is impossible on a steel. So minor changes in pitch as you move up the neck is just part of the instrument.

As far as cabinet drop, I think it is something we will have to live with. The problem is that we are tuning a maple top ( a very rigid surface) with the tension from a 10 to 12 strings on each neck. It is impossible to isolate the stresses from one string across the others on the guitar body. As you tune all of the strings up to pitch this effect is cumulative and the top of the guitar becomes a "stressed member". When this occurs changes from one string or from forces pulling on the cabinet (pedals and levers) impacts the cabinet. The only solutions would be to built a structure so rigid that it is impervious to the changes (such as MSA's carbon fiber millenium) or to have all of the axels and pedals/levers in a rigid sub structure and have the body of the guitar mounted to the substructure and have the only mechanical connection be through the pull rods into the changer. A possible third solution would be to build a "truss rod" into the cabinet that could be tuned to counteract the cabinet drop.

So as you can see this is not an easy issue to overcome. It could be, but it would add weight or cost and alot of complex engineering. And unfortunately the pedal steel market is not big enough to allow this type of research.

David Doggett · Post by **David Doggett** » 2 Jun 2005 9:17 am

Bill, the steel doesn't have the same intonation problems fretted guitars do. On fretted guitars the bridge adjustments account for the fact that, as you mash the string down to the fret, the different guages of string deviate from pitch to different degrees. The solution is to adjust the bridge so that the overtone at the 12th fret is in unity with the fretted note at that fret. Steel guitars do not have this problem because we are not forcing the strings down to the frets. Thus, steel guitars work just fine with straight, unadjustable bridges.

There is a slight problem with bar pressure. If you tune everything perfect open at the nut, then you put your bar on say the 8th fret, the bar pressure causes the different string guages to alter the intervals slightly. But checking this with a meter I find that there is less than 1 hz (4 cents) difference, and it is not worth worrying much about.

Concerning cabinet drop there is one thing mentioned in the above thread that I have heard in other recent threads. Some manufacturers claim that if you have a body so rigid that there is no cabinet drop, it kills tone. It may well be that a very rigid body produces more pronounced high overtones and a harsher tone. A less rigid and more resonant body may de-emphasize some of the high overtones and produce a more mellow tone.

Billy Carr · Post by **Billy Carr** » 6 Jun 2005 1:31 am

Well, here's my opinion on cabinet drop after 30+ years of playing pedal steel. I believe that every guitar is different. I think you can take, let's say for example: Take five guitars, D-10's made by the same builder at the same time. I think each one will be a little different even though they were made at the same time with the exact same materials. A player has to play and control the guitar. In other words, you have to make the guitar do what you want it to. By knowing your instrument a player will learn what little things are not perfect and will work around it. I've yet to see any guitar that is in perfect tune in all positions using pedals and KL's. Even though steel guitar builders have greatly improved there products over the years there is still a need to know the guitar and its limitations. I think the only way a perfectly tuned guitar w/o cabinet drop or any other problems will be made is by having all the raises and lowers controlled by a computer that is built into the guitar. Then with a computer making the necessary changes that'll take all the fun out tinkering and worrying with a steel guitar. Of course, a guitar will probably cost 20,000.00 by then! Just my opinion!