Compensation for wound A string

[Steveareno]

When using a wound A string,would you not need to have a bridge built with proper compensation,i.e. proper string length,i.e. correct intonation?

[George R. Lane]

I just put a set of TI's on my Weber Vintage A and on my Yellowstone and it did not affect the intonation.

[Jim Bevan]

The farther up the neck you go, the more out it'll get.

On my two Rigels that have TIs I have mandola saddles installed -- they're the same size, just plug-and-play!

[foldedpath]

I used TI Starks for a while, and I didn't notice a problem with the wound A's. if you're using TI's, make sure you're using the medium gauge (in their terms "Stark") set.

The farther up the neck you go, the more out it'll get.

Well, technically speaking, what happens is that the intonation on any mandolin is theoretically perfect at the nut, and at the 12th fret. That's why you check bridge position by comparing the fretted note with the harmonic at the 12th fret. It's that area around the 5th to 7th frets that are the most likely to be a little squirrely in intonation on fretted instruments like guitars and mandolins, due to the nature of the 12-tone equal temperament system.

The closer you get to the 12th fret, the more likely the intonation will actually improve (assuming a good bridge position and compensation), instead of getting worse.

(/end pedant mode)

[EdSherry]

Re foldedpath's comments: seems to me that his statement is true only if the bridge is correctly compensated in the first place. As I understand it, the OP's concern is that a "normally" compensated bridge is compensated for a plain (unwound) A string, and switching to a wound A string would change the situation and would (ideally) require an adjustment to the bridge. But maybe I'm missing something.

[Bruce Clausen]

That's right, Ed. A wound string needs to be shorter than a plain string of the same diameter in order to fret accurately. If you've got the wrong string type for the saddle compensation on your instrument, you can tune it up at the open string, but it'll get farther and farther out as you go up towards the 12th fret and beyond. With a wound A string, using a mandola saddle is a brilliant idea that never occurred to me-- thanks, Jim!

It isn't equal temperament that creates the problem. If all your strings were of the same type and diameter (and height), there'd be no compensation problem. But since we use different gauges and types, each string needs a slightly different scale. That's what we're compensating for with our jagged saddles. But the fact that the frets themselves go straight across the neck, instead of imitating (progressively) the pattern of our saddles, means that intonation will always involve a certain amount of compromise.

[foldedpath]

Re foldedpath's comments: seems to me that his statement is true only if the bridge is correctly compensated in the first place.

Right, I'm assuming a good setup with correct bridge location. I was addressing Jim's point about "The farther up the neck you go, the more out it'll get," which is true up to a point (5th-7th fret). Then it gets better as you go higher, which I'm not sure many people realize. And of course it gets worse again as you go past the 12th fret, but who goes there.

As I understand it, the OP's concern is that a "normally" compensated bridge is compensated for a plain (unwound) A string, and switching to a wound A string would change the situation and would (ideally) require an adjustment to the bridge. But maybe I'm missing something.

Yeah, that's just something you'll have to check with each string brand. I didn't find it out far enough, with the wound TI A's on my stock compensated bridge to bother with making a new one, but your mileage may vary. Just check it with a good tuner at the 12th fret (fretted vs. harmonic) and you can see if it's bad enough to justify the work of making a new compensated saddle.

[Ivan Kelsall]

I've used both D'Addario J74's (my usual string) & FT74's on both my Mandolins. The wound "A"s on the FT74's gave no intonation problems at all on either,& i play well over the 12th fret quite a lot. The only reason that i don't use the FT's all the time, is the cost.If there was an intonation problem,i wouldn't even consider them as my 'usual' string.
This question has arisen a few times before & i always think of My Guitar,with it's fixed bridge & thin saddle,& how when i've experimented with varying string gauges,there have been no intonation problems. Guitar string gauges vary more than Mandolin string gauges when going from light to medium to heavy & you'd maybe expect a 'few' intonation problems,
Ivan

[mandobassman]

I've always had intonation problems to some extent with round wound strings on every mandolin I have ever owned. My current Breedlove has the best intonation of any that I have had. Not only did I not have problems with TI's, but my intonation actually improved with them. I would have thought the opposite but for some reason my intonation is almost perfect with the TI heavy.

[Rolfe]

Bruce is right: the string length---nut to saddle---often needs to be shorter. The traditional "Loar" saddle puts the A string way long. When I make my saddles, I have one pattern for regular strings and another pattern for Thomastik strings. The second pattern reduces the "set-back" of the A saddle by about half.