Viola C String Slapping

November 29, 2025, 9:44 AM · I recently acquired a wonderful, resonant viola by William Whedbee. It had Evah Pirazzi greens when I bought it; I noticed a slapping sound in the C string when moving between the open C and open G. I tried Evah Pirazzi Golds to see if there would be any improvement, but it seems to have gotten worse. The good news is that this change makes me believe that the type of string can help.
Could it be a string tension issue? If so, do I need a string of higher tension or lower tension? Would a particular kind of string work better? I could try them all--gut strings, different gauges, etc.--but I welcome a shortcut if anyone has knowledge or experience here.

Replies (12)

Ben Furman

Edited: November 29, 2025, 10:02 AM · It sounds like the bridge arch may be too low. A higher-tension C string could help or, counterintuitively, a higher-tension A string might limit excessive bridge movement.

Does the action seem low?

Tom Holzman

November 29, 2025, 10:08 AM · You should probably take this problem to your luthier. S/he can hear the sound you are complaining about and recommend a fix.

David Burgess

November 29, 2025, 12:26 PM · There may not be enough scoop (concavity) in the fingerboard. It may need to be planed/reshaped.

Stephen Symchych

November 29, 2025, 4:01 PM · Time to call in the pros.

Then, come back so we can all tell you what strings you will like best.

Matt Arnold

November 29, 2025, 4:09 PM · Thanks, all! The action seems about perfect--the action was too high on my old viola which made my fingers hurt, but this one feels very comfortable. I will contact the folks in the know at the shop to find out what's going on and will report back.

Ben Furman

November 29, 2025, 5:33 PM · Very funny, Stephen….

David is spot on as usual!

Nickie McNichols

November 29, 2025, 6:45 PM · Ben, I concur.

Paul Deck

November 30, 2025, 7:07 AM · If you're hell-bent on trying something yourself, you could try putting a parchment on your bridge for the C string to raise it up a tiny bit. If that helps, then you're going to luthier anyway, so that they can confirm it's the right sort of fix, to do it properly if so, and to do something else if not.

Jake Watson

November 30, 2025, 7:30 AM · This may be a really ignorant question to ask (but a legit one), but what is meant by "action"?

Don Noon

Edited: November 30, 2025, 9:09 AM · "Action" is height of the strings over the fingerboard.

It would be good to know what is slapping where. I find it a bit odd that it mostly happens in transitioning from open C to open G... which might imply that the strings are hitting each other, which might imply that the string spacing is too close. Does the C slap if you lift the bow off of the string, or just transitioning to the G?

Usually the problem is the string hitting the fingerboard, which can be a number of things. Action too low is one, too little scoop (action too low in a critical spot) is another, or possibly the crosswise curve of the fingerboard is too flat. Or there could be ripples in the fingerboard, but that's normally a fingered string issue, not so much an open string.

Adrian Heath

November 30, 2025, 10:25 AM · On my rather narrow JTL viola, I can make my open G and C collide in loud double-stops, with a fearful rattling sound!

Matt Arnold

December 1, 2025, 1:37 PM · Don - It's very hard for me to discern where along the string the slap is occurring. I cannot seem to produce the sound on the C string alone--only when transitioning between strings--but the C and G strings don't seem to touch each other, even when vibrating at the loudest dynamic I can muster. And yet when I'm playing the barest pianissimo, that little buzz zings up through the string as soon as the bow touches the G string. I've tried playing the viola like a cello to have a different birds-eye perspective and I can't seem to replicate the sound.

Viola C String Slapping

Replies (12)

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