I'm replacing the saddle on a 12 string guitar. Should it be slotted to accurately space the strings or left smooth like a 6 string?
Smooth like a 6 string. The bridge pin hole spacing pretty much keeps things in place on that end.
Unless it has (hopefully not) a trapeze tailpiece, like a Harmony or Gibson B-45-12. But then there would probably be more "pressing" issues than a notched saddle.
Thank you both for your replies. It's a Sigma guitar made by C.F. Martin in Korea.
I have never seen a 12 string that was playable without having the saddle notched.
Also , smooth like a 6 string is misleading , since many 12 string players prefer a set-up in which the tops of the strings are in the same plane, which obviously rules out a "smooth " saddle.
It's all about player preference, and individual string gauge preferences come into the equation as well.
If a player likes to play tuned down a couple of tones, ala Leo Kottke, he will want a heavier gauge string, and that throws everything back into the melting pot.
So all in all it is impossible to generalize and say that the bridgepin hole spacing will take care of things.
Unless, of course, you are actually making a guitar for a customer who knows exactly what gauges of string he wants, and what distance he wants between each pair, and you have a CNC milling machine ( or at least a table with a digital read out) which will drill the bridgepin holes out to the required accuracy.
Hmmmm ... the plot thickens ...
I'll go ahead and disagree with you, Murray, in that an acoustic 12 string is an instrument that is a compromise, at best, with compromised intonation and string height. I find that the differing string heights in the bass register allow me to dig in more and catch the string pair with the tone I prefer - I can prefer the treble or bass string as needed, thanks to the different angles. (I would immediately agree that the angle is enhanced or degraded by the spacing of the strings and pin holes, though.)
I can see how some people would prefer the tops in the same radius (not plane, of course), so then my question is, how does having the tops of the strings in the same radius affect intonation and playability? I'm not sure I want to be pressing down treble strings even further than I already have to, which I assume to be the tradeoff when those treble strings are raised. (FWIW, I'm playing a Guild D212, neck reset for great angle, and heavy John Pearse strings tuned to C#.)
My 2 cents.
I wonder why Martin, Taylor, Breedlove, Collings and scores of other QUALITY makers don't use notched saddles.
Oh yes, notched saddles are just WRONG on a 12 string or a 6 string acoustics.
It compromises the string break angle and unless you "round over" each notch, you're going to get a less than optimum tone. Actually, customer notched saddles are one of most frequent reasons that I have to cut a new smooth topped saddle. The results have ALWAYS resulted in a better sounding & playing instrument.
If players have trouble with the strings 'holding their spacing", they should give a good hard look at their technique.
So my opinion: ALWAYS use a smooth well profiled saddle on acoustic guitars.
The tops of the strings would not remain 'even' once the guitar is fretted or capoed. Would not all of the frets would have to be 'wiggly' to achieve this? Sorry for the high-tech terminology.
In the immortal words of Strother Martin , in Cool Hand Luke ..."what we got here is a failure t'communicate" ...
I am not suggesting for one minute that cutting 6 V's in a saddle should be normal practice.
OTOH, nor do I subscribe to the opinion that it is written on tablets of stone that the top of a saddle MUST be a smooth continuous curve.
Getting the notches out of the way first ...obviously no builder worth his salt is going to commence a build with the intention of spacing the string by means of notching the saddle.
However, when a customer has acquired a guitar, maybe a second hand buy with which he is happy, except for the fact that the string spacing at the bridge doesn't entirely suit his style, then there is absolutely no problem with cutting a minute notch on the bridgepin side of the saddle to accommodate his preferred string spacing. And this would apply to 6 string and 12 string instruments.
I concede that sometimes this is impractical ...on guitars with pyramid bridges, where the breakover angle in the bass strings is almost vertical, then it would be a problem. If you have a shallower breakover angle, then it is almost always doable. I would stress that the only justification for notching a saddle is to alter the string spacing ...I mean you wouldn't lower the action by such means ...LOL ...as if ...
The whole point is that the objective should be to make the guitar as playable as possible for each individual customer, and to be honest, the suggestion that any guitar tech should ever presume to tell a customer that the way round a problem is for them to improve their playing technique makes my gut squirm.
Maybe, just maybe, the string spacing that all the builders of QUALITY guitars use might just not suit every player.
To get very slightly off topic, Huss and Dalton stick rigidly to the company policy of spacing the strings at the nut using equidistant string centers, whereas every other major manufacturer follows the Martin example of equidistant string spacing .
Now, although personally I detest equidistant string centers, the fact is that there are actually some players who prefer this. So they get their nuts replaced ...nothing wrong with that.
So, by the same token, there is nothing wrong with altering the string spacing at the bridge by discreetly notching the back of the saddle ...it's not like you are going to go hell for the sin ...
I will comment on the "smooth continuous curve" in a separate post ...
"the suggestion that any guitar tech should ever presume to tell a customer that the way round a problem is for them to improve their playing technique makes my gut squirm."
Technique observation or knowledge of the customer's technique is a critical part of the evaluation process, and is often the actual cause of the problem.
I'm sorry if I and thousands of other guitar technicians who are practicing professional musicians make your gut squirm. We truly are. Might I suggest an antacid? :(
Pepto and a large glass of water should take care of it, just remember to sip the water. :)
Thanks for saying that - I regularly give my customers advice about their playing style when it's part of the pathology of the fix - same as I advise customers who are "death grippers" that their accelerated fret wear is avoidable by changing their muscle memory via changing their left hand technique etc etc - sometime I give advice simply because a poor hacker needs a break or is clueless - it's a bit like your doctor advising you to change your lifestyle to avoid continuing illness - all part of a professional service I would have thought.