String Whistle on Reso

Jerry Overstreet · From: Louisville Ky

Todd or Greg...other experienced builders/mechanics please.

Neither expert nor novice. Done a few upgrades on spider bridge resos but haven't come across this problem 'til now.

Chinese spruce/mahogany squareneck delivered with mahogany soundwell, ebony over maple bridge inserts, and what appear to be Ping 3/plate tuners.

Upgrades include Quaterman and bone nut, leveled and sanded stock cast spider. Not a #14 unit, but seems to be an acceptable and usable clone. Scale and intonation checked pretty thoroughly with no discernible discrepancies.

Problem is, I'm getting a nasty whistle or type of ghost overtone when passing the bar over frets 2, 5, & 8 in particular and most noticeable on the first string. Tension screw has no effect nor does swapping out a variety of string nuts and strings.

Sounds pretty good otherwise, but a little weak on volume.

Suggestions welcome. Thanks for taking time to read and reply to my query. JO.

Jim Bates · From: Alvin, Texas, USA

Try some simple experiments to try and isolate problem: weave some felt or cloth strips through the strings between the nut and the tuners and notice any change, if any; try the same weaving of cloth through the strings between the bridge and the tailpiece; see if any of the ball ends of strings are maybe touching top of coverplate, especially when you rest your hands on the strings; check for loose tuner buttons or gears.

I have a similar sound on my Tut Taylor on the first string around the 11th fret. This seems to be more related to a natural resonant frequency of the whole sound box (body).

Thanx,
Jim

Todd Clinesmith · From: Lone Rock Free State Oregon

Hi Jerry,
Is the spider alligned and centered ?
As Jim said it may be certain frequencies causing this. Do the ghost notes come out playing the same notes on the second string?
If not I think you may have a burr in a slot on the high string of the bridge. You can take a appropriate nut file and very lightly clean the slot up.... or try using a string. I would not try remoing any material just kinda roll the nut file lightly in the slot.
Let me know what you find out
Todd

Alan Brookes · From: Brummy living in Southern California

When I first read the title I imagined someone was fitting a whistle to a Dobro. Embarassed

Jerry Overstreet · From: Louisville Ky

Thanks guys. Jim, I've tried most of the things you suggest...may be worth another look though.

Todd, the zing is there on probably all the strings at the same frets but is only really annoying on the first string, so I'd have to guess it's something to do with particular intervals of the length of scale v. frequency.

I've been reluctant to mess with the bridge insert, but I'll try your suggestion.

I've had it apart a few times and tried to make sure the spider is centered north/south and east/west as near as I can tell.

I'll take another look at you guys' suggestions and report any progress. Thanx again. JO.

Todd Clinesmith · From: Lone Rock Free State Oregon

What gauge string do you have on the high string?
I like a 17, some folks like 18's too. 16's were /are still the standard gauge but that seems to be changing these days.
Anyways try a fatter gauge string before taking a look at the bridge.
Todd

Charley Wilder · From: Dover, New Hampshire, USA

The tailpiece laying on the cover plate can at times cause problems. Usually a rattle but it might be worth checking if you haven't already.

John Billings · From: Ohio, USA

CW said, "The tailpiece laying on the cover plate"
Whenever I have this problem, I go to the drugstore and pick up some Dr. Scholl's Moleskin. Sorta felty stuff with a sticky back. Cut to shape and stick it on.

Jim Bates · From: Alvin, Texas, USA

You may just be geting 'wolf tones' or natural resonace frequencies of the whole setup. It's very possible. If so, all of our suggestions will not solve it.

Thanx,
Jim

Eugene Cole · From: near Washington Grove, MD, USA

One this to try (diagnostically) is to tune the guitar down a full step and see if the wolf tones migrate up a couple of frets. If they did migrate then you probably have instrument which has some awkward resonant frequencies which will rule out (for the most part) the standard setup issues.

Let us know your results and we can refine our suggestions.
_________________
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Sierra U14 8+5 my copedent, 1972 MSA D10 8+4, and nothing in the Bank. 8^)

Jerry Overstreet · From: Louisville Ky

Thanks everyone. Detuning to D seems to mask the volume of the whistle somewhat, however the problems remain at the same frets. Always at the same frets on all the strings in lesser degree from first string to sixth successively.

A small tweak of the tension screw seems to have lessened the effect some, but it's a minor improvement.

I think the next step is to try different bridge inserts, perhaps solid maple or another set of ebony capped ones.

I'm probably gonna swap the spider for the #14 at some point but hadn't planned on it right away.

Could be it's just the nature of the beast and it's the best it's ever gonna do.

More later as things develop.

Incidentally Todd, this is #3 string on the 1st....all 16's from different mfgs. I will try the larger gauge first before another disassembly.
Thanxalot everybody.

James Harrison · From: New Brockton, Alabama, USA

Jerry: Did you have these wierd sounds before you started the modifications? I have some wierd pierceing tones on some notes on the first and second strings when I am plugged in using a Piezo Pickup, but not when I use a Magnetic Pickup. I just wondered if it might be one of the mods that caused the wierd tones.
James

Jerry Overstreet · From: Louisville Ky

Hi James...ya' know, I only played it for a short time before changing the cone, but I'm sure there was an issue with the first string in particular. I don't recall if it was the exact thing, but I know I didn't like it.

I'd be doubtful if anything could be caused by the Quarterman given my past experience with them. The first bone nut I installed was a preslotted one from Beard. I made another one myself from a blank with a little different string spacing. No difference whatsoever.
I still haven't disassembled it further as of now, but I plan to give the bridge inserts another look. They just look so good and appear to be ebony over maple, so I didn't change them out.

Given the source of mfg., I don't expect a great sounding instrument, but everything looks and feels so nice I'm hard pressed to condemn it. It's a pretty nice sounding and playing, nicely finished budget axe, but I think there's a small detail that I'm missing. We'll see Exclamation

Gregg McKenna · From: South Windsor, Connecticut, USA

Some good advice from the others.

If you still have the problem, pop the string out of the bridge slot (up onto the wood) and see if it disappears. If so, you know it's in your bridge slot. If ok, try the same to the nut.

I've actually seen/heard of similar problems caused by the tuners (such as loose bushings). Most of the time,it affects the 1st string. Very Happy

Bob Hickish · From: Port Ludlow, Washington, USA, R.I.P.

Jerry

Several years ago I has that going on with my
"Dobro" brand Dobro . it happened around fret
5 through 8 , drove me nuts . what I discovered
was the string was not snug over the tail piece
ridge . by flexing the string up or down it would
go away . as i remember I reshaped the tail ridge
upward . if you have a high angle brake over the
bridge , you may need to lift the tail piece up .

Maybe this is what has happened to your dobro Question

Good luck
Hick

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