Cabinet drop

[Larry Behm]

Many guitars have some, some more than others, you can hear it sometimes without even plugging the guitar into an amp.

My 1970 fatback PP Emmons might have a 1/2 cent on its worst day. Neve had a guitar like this one, stays in tune, plays great for a PP, and sounds fantastic every single time I lay the wood to her.

[Lane Gray]

Most, but not all, severe cabinet drop is due to operator error. Any foot pressure beyond reaching the stop MUST deform the cabinet.

[Jeffrey McFadden]

Most, but not all, severe cabinet drop is due to operator error. Any foot pressure beyond reaching the stop MUST deform the cabinet.

Interesting point. I know that controlling my pedal pressure and travel is one skill I am still struggling with. I'll be keeping this point in mind from today forward.

[Georg Sørtun]

I know that controlling my pedal pressure and travel is one skill I am still struggling with. I'll be keeping this point in mind from today forward.

Don't worry too much about it. "Bodydrop" detuning on your GFI won't change much with varying pedal-pressure…

[Jeffrey McFadden]

I know that controlling my pedal pressure and travel is one skill I am still struggling with. I'll be keeping this point in mind from today forward.

Don't worry too much about it. "Bodydrop" detuning on your GFI won't change much with varying pedal-pressure…

Cool. Thanks.
I can go back to just worrying about getting both pedals all the way down at the same time on both pedal pairs (A&B, B&C).
I'm gaining on it but it ain't whipped yet.

[Robert Rhea]

The tuning on my guitar starts dropping as soon as I touch a pedal. To me, that would indicate a problem with the changer. Maybe not enough lubrication so the other fingers don't move when a pedal is depressed? Maybe? Is that even a possibility?

[Georg Sørtun]

The tuning on my guitar starts dropping as soon as I touch a pedal. To me, that would indicate a problem with the changer.

A quick check is to tune the high B and G# strings up to C# and A respectively, and down again, without touching any pedal/lever, and listen to how both E strings hold their tuning during the procedure. If the E strings detune, either the changer or the keyhead, or most likely both, are not stable – "give" under varying tension.

Once you have performed this test, you will have established if change in string-tension OR pedal-pressure is to blame for the "bodydrop" detuning, and can start looking for what to do about it.

[Tucker Jackson]

The tuning on my guitar starts dropping as soon as I touch a pedal.

Try tightening the screws that hold the end plates to the cabinet.

Also, loosen the strings and tighten the screws connecting the changer to the body.
.

[Lane Gray]

All of the screws, not just endplate screws.
Cabinet drop that severe is an indication of a problem, and not just a case of "they all do that."

[Cartwright Thompson]

I’ve got a ‘70 fatback D-10 and the cabinet drop is barely noticeable. Even on my ‘76 you have to really pay attention to hear it.

[Brint Hannay]

A quick check is to tune the high B and G# strings up to C# and A respectively, and down again, without touching any pedal/lever, and listen to how both E strings hold their tuning during the procedure. If the E strings detune, either the changer or the keyhead, or most likely both, are not stable – "give" under varying tension.

Great idea. Can't believe I never thought of that!

[John Goux]

Emmons PP guitars are almost immune to cabinet drop. Don’t know why.
A D10 will give you less than an S10.
A Zero pedal left of ABC will add 2-6 cents to your cabinet drop.
12 string guitars are worse than 10 string guitars.

This is not operator error. (Sorry Lane) You can exaggerate it by over pressing but a light touch will not negate the tuning drop.

The least cabinet drop would be an Emmons PP D10.
Next least, any other D10 with no zero pedal.
The worst cabinet drop is going to be an S12 with a zero pedal.

John

[Georg Sørtun]

Last time I measured I managed to push the (regular) low E down just short of half-a-cent on this "slightly modified" Dekley…



Couldn't provoke any of the other strings into measureable detuning no matter what normal or extreme methods I used, so I'm happy with the stability of the "mod".

Now, the force on the pedals have no detuning-effect via the frame on a Dekley – no acual "bodydrop" regardless of number and placement of pedals. Whatever detuning one can provoke in an unmodified Dekley is caused by varying string-tension, as the top-plate can "give" where changer and keyhead are attached.


Detuning related to varying string-tension can be counteracted on pretty much all All-Pull PSGs, but it makes sense to figure out where exactly the weaknesses are before doing anything about them. Sometimes it is just some badly fastened screws, or maybe some screws could do with large washers to spread the forces they are exposed to.

[Robert Rhea]

I tighten up a couple of screws, but most were tight. It's not as bad as I originally thought. The tuning doesn't start dropping immediately like I was thinking. It does however drop enough to be noticeable to the ear when both A and B pedals are down. How much, I'm not sure. How do you measure cents on a Peterson Strobo HD tuner? Is there a way to show the actual frequency and not just watching the rings move clockwise or counter-clockwise to know if you're in tune?

I didn't get a chance to check for drop on the E strings by tuning the B and G# up to C# and A. I'll do that tomorrow.

Thanks for the input!

[Lee Baucum]

I played an S-12 Emmons push/pull for quite a few years.

It had very minimal cabinet drop; however, when a string would break, all the remaining strings would go out of tune. After replacing the string and bringing it up to pitch, the guitar would be in tune again.

[Donny Hinson]

Is it really "cabinet drop"? One easy way to test is to hook up your tuner, pick your 5th 0r 6th string, and then take your thumb and press down hard on the center of your guitar.

"Drop" can come from many things, yes...including too much foot pressure on the pedals. Once in a great while, it's a changer or end plate screws. But other than that, I've never seen a case where it made a guitar unplayable. In most of the cases I've seen, the cabinet drop was nothing but a player worrying too much about something that really wasn't a significant issue.

Play the guitar, don't let the guitar play you.

[Per Berner]

My ears are rather sensitive, and on a Sho-Bud Pro III i owned about ten years ago the cabinet drop was audible – but not to any worrying degree. My S10 PP has no audible drop, and neither has my Hybrid Zum (which is equipped with compensators). Checking with an old Korg tuner, there is some barely noticeable movement of the needle, but my LED Sabine tuner registers no change in pitch. Guess I've been lucky.

[Georg Sørtun]

Is it really "cabinet drop"? One easy way to test is to hook up your tuner, pick your 5th 0r 6th string, and then take your thumb and press down hard on the center of your guitar.

Done that … only I used a simple lever and weights to put at least 20Kg (44lbs) downward force on the center of the front apron/rail, as that is where the pedal-pressure may have an effect on the body/frame.

Results are not surprising:
- Dekley S10 slimline (modified): no measurable drop.
- Dekley SD10 slimline (original but with backneck taken off): no measuarble drop.
- GFI Ultra SD10 (not played much): <0.1 cent drop worst case.
- MSA S12 "Supersustain" (old and pretty worn): <0.3 cent drop worst case.
… clearly no audible "bodydrop" detuning in any of them.

However, when actually pushing those pedals, things sounded, and measured, a bit different:
- Dekley S10 slimline (modified): <0.5 cent drop worst case.
- Dekley SD10 slimline (original but with backneck taken off): <2 cents drop worst case.
- GFI Ultra SD10 (not played much): <8 cents drop worst case.
- MSA S12 "Supersustain" (old and pretty worn): <14 cents drop worst case.

As I like "stable platforms", the above is part of the reason I prefer to play those old Dekley
(To have mentioned it; my Dekley S10 was in the around 5 cents drop category before I modified and "stabilized" it in the early -90s.)


Anyway, all my testing over the years (since back in the mid -80s for the now modified Dekley), indicate that while most All-Pull PSGs seem to handle vertical forces well enough for comfort – little to no actual "bodydrop", various All-Pull PSGs ability to handle horizontal forces – mainly varying string-tension, varies greatly.

Push-Pull and Pull-release PSGs are different in that changer-parts for individual, non-changed, strings hang on their rods – not against a common stop-plate, which means they naturally become more insensitive, although not entirely immune, to varying string-tension than All-Pull PSGs.

[Donny Hinson]

Results are not surprising:
- Dekley S10 slimline (modified): no measurable drop.
- Dekley SD10 slimline (original but with backneck taken off): no measuarble drop.
- GFI Ultra SD10 (not played much): <0.1 cent drop worst case.
- MSA S12 "Supersustain" (old and pretty worn): <0.3 cent drop worst case.
… clearly no audible "bodydrop" detuning in any of them.

However, when actually pushing those pedals, things sounded, and measured, a bit different:
- Dekley S10 slimline (modified): <0.5 cent drop worst case.
- Dekley SD10 slimline (original but with backneck taken off): <2 cents drop worst case.
- GFI Ultra SD10 (not played much): <8 cents drop worst case.
- MSA S12 "Supersustain" (old and pretty worn): <14 cents drop worst case.

As I like "stable platforms", the above is part of the reason I prefer to play those old Dekley
(To have mentioned it; my Dekley S10 was in the around 5 cents drop category before I modified and "stabilized" it in the early -90s.)

Correct Georg, those examples make it obvious that only some of the drop is in the cabinet itself. Other causative areas include the changer axle, movement of the changer itself, nut movement/deflection, cross-shaft movement/deflection, and the keyhead. Little problems become additive, each part in the system contributing a small amount to the equation. Still, in most all cases, I think what is called "cabinet drop" doesn't affect actual playing. It does serve as a worry-point, though, for those who put too much emphasis on digital tuner readings.

“Not everything that can be counted counts, and not everything that counts can be counted.”

William Cameron

[Georg Sørtun]

Correct Georg, those examples make it obvious that only some of the drop is in the cabinet itself. Other causative areas include the changer axle, movement of the changer itself, nut movement/deflection, cross-shaft movement/deflection, and the keyhead. Little problems become additive, each part in the system contributing a small amount to the equation. Still, in most all cases, I think what is called "cabinet drop" doesn't affect actual playing. It does serve as a worry-point, though, for those who put too much emphasis on digital tuner readings.

Right. "Bodydrop" may be a misnomer, but we all know what it means

As one who tune the chosen reference note – the high "A" w/B-pedal down – with the help of a tuningfork, and all else by ear, I'm not the least worried about what I cannot hear. However, as my ears won't tolerate more than about 2.5 cents relative detuning for long, I find a number of PSGs next to unplayable. I need a stable platform so I intentionally can play in and out of tune, and not be forced to compensate while I'm busy playing.
Enforcing JI on sweetened tunings along with ET tuned instruments and make it sound right, is hard enough on both the instruments and me. Don't need the added distractions that comes with playing inferior instruments, whether it is "bodydrop" or other issues at play.

That I can produce measurements is simply because the necessary instrumentation – high resolution frequency counters, generators, scopes and whatnot – is part of my professional toolset … totally unrelated to being a hobby-musician.
There is even a StroboPLUS HD tuner laying around somewhere, that I have used on rare occasions when I either have misplaced my tuningfork or when higher accuracy isn't called for.

[Chuck Lemasters]

My Rains guitar seemed to have noticeably more cabinet drop than the Carter. After reading this thread, I decided to check screws for tightness, flipped the guitar over, everything was OK. I sat the guitar back up and checked the allen head screws that hold the changer, found the two screws on the treble side loose. So loose I thought at first they were stripped. Tightened them and voila! Problem solved. The tuner shows a slight amount of detuning on the fourth sting E with pedals A&B down, but not enough to worry about. Another benefit of being on the forum. Thanks guys!

[Steve Spitz]

I’m hoping someone with greater mechanical aptitude than me will chime in here with a simple caveat:

Before you flip over that steel and tighten every screw you can find, make sure the screws you choose to tighten actually affect the stability of the tuning equation, without tightening anything that only reduces the guitars ability to resonate.

Some screws that hold a neck on, for example, if overtightened, will reduce the guitars ability to resonate. Ive learned this the hard way. If someone can learn from my mistake, I’m happy to mention it.

[Dick Wood]

Has anyone ever put some blocks under the pedal bar to see if that slows,stops or has any effect when you step on the pedals?

[Georg Sørtun]

Has anyone ever put some blocks under the pedal bar to see if that slows,stops or has any effect when you step on the pedals?

The pedal bar gets pulled upwards – towards the body – when you push pedals. Thus, putting anything under it has no effect on "bodydrop".

[Georg Sørtun]

Some screws that hold a neck on, for example, if overtightened, will reduce the guitars ability to resonate. Ive learned this the hard way. If someone can learn from my mistake, I’m happy to mention it.

Right … good you mentioned it.

Especially some PSGs with metal necks (but some with wood necks too) get their sound and sustain in part from having the neck and body vibrate against each other. They may have the neck tighten well to the body at one end – usually the changer, and more loosely towards the other end to allow for vibrations. Tightening all screws along the neck "just to be on the safe side", will literally kill this effect and make these instruments sound dead.

Focus on screws that hold the changer and keyhead firmly against the body – mainly those towards the end-plates, as these are the screws that take up all string-tension.