Replies to This Discussion

Permalink Reply by Crow on June 5, 2010 at 4:19am

@wes
i'm playing with only the necessary force. i'm a real finesse kind of player, and have a light touch. if i use any less pressue, the strings buzz under my slide.

i've built both fretted and slide instruments, and the build method always remain true, with the same results. the bridge must always be "sweetened" once it is strung up

i have a very sensitive ear, and always scrutinize the fret placement, the bridge, the trueness of tone all the way up the neck, on every instrument i play.. guys at the guitar store hate me... LOL

...and let's not forget, i don't play only one string at a time, one note at a time... i strum all three strings all the time, so the strings see a lot more action and require a little different treatment in slide technique and a heavier hand. the middle string is forced to recieve the median pressure which is dictated by the pressure needed by the strings on either side of it...

didn't mean to get technical. i'm sure you know what i mean LOL

what style do yo play?

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Permalink Reply by Wes "I'm Baaaaack" Yates on June 5, 2010 at 7:01am

Crow, No offense intended I'm sure. I've just never seemed to experience string tightening when I play slide. Didn't know why you did. Was just something to consider.

When I teach folks to play slide, I usually tell them to stick out a finger. I lay mine across theirs and say 'this is a good start. Not any more pressure." I play slide on fretted and unfretted, flatpick and fingerpick, so...

-WY

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Permalink Reply by Larry McInnes on June 5, 2010 at 11:18am

I think Einstein and probably Mr. Spock both said that the simplest scenario is most likely the truest. I like the idea of moving the nut back 1/32" since it's the easiest solution, that coupled with lowering the nut and bridge height a bit. Have to start somewhere, right? Thanks again guys for your willingness to share your brilliance.

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Permalink Reply by Andrew Fowle on June 5, 2010 at 2:37pm

I've never built anything before, and I'm attempting to design an instrument that is fretless, but has fret markers. I found a fret calculator* that lets you pick your scale length, how many notes per octave you want (most folks here would want 12) and whether or not you wish to include compensation for having frets. I figured if I used this calculator, chose no compensation, and stuck like glue to to the figures it gave me for that scale length, it would be smooth sailing. I hadn't thought for a second about the nut height or the bridge height!!

The only info I've found about what heights to set the nut and the bridge has been relative to fret heights. Given that I won't be using frets, I'm still in the dark on this one. Any thoughts?


*http://windworld.com/features/tools-resources/exmis-fret-placement-...

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Permalink Reply by Crow on June 5, 2010 at 10:14pm

the only thought i give to nut and bridge height (i build mine for slide as well) is "will the strings be high enough to play without my slide hitting the neck?
just build it, and start to play. the areas that need improvement will be clear soon enough. the first few builds are always learning experiences for us

...my videos may be of some help....

good luck!

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Permalink Reply by Wes "I'm Baaaaack" Yates on June 6, 2010 at 2:45am

Cool baby! So lets say you muck it all up.... EEEEEEeeppppps!. No problem. Add on 1/32" shim to the end of the fretboard and call it a 'design element' so the nut is back to where you started. Make another nut or again, shim that too. Make another bridge. Voila! So long as you use(d) your fret calc and placed the frets in the right spots, you're golden.

Good luck.

-WY

Larry McInnes said:

I think Einstein and probably Mr. Spock both said that the simplest scenario is most likely the truest. I like the idea of moving the nut back 1/32" since it's the easiest solution, that coupled with lowering the nut and bridge height a bit. Have to start somewhere, right? Thanks again guys for your willingness to share your brilliance.

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Permalink Reply by BenBob on June 6, 2010 at 7:43am

Larry, did you fix your intonation at the 12th fret first? You said the notes were getting sharper as you played up the neck, and nearly 1/2 step sharp at the 12th fret... symptomatic of the bridge needing better placement, not a nut issue.

The talk of nut compensation is somewhat related, but the symptom of nut issues is that it plays perfectly at the 12th fret, but is sharp when close to the nut.

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Permalink Reply by Murray on June 6, 2010 at 10:42am

I'm not sure I'm taking the nut setback and bridge position compensation answers with the same lack of bias, due to problems I've had...so I'm thinking about this...on my previous mods/builds (non-CBG), the neck and body belonged together (made for each other), so the action and bridge were the only options.

Thinking about this a bit... (and I admit I haven't read that link yet, but I will!)
If the nut position is altered on the neck, it has changed the scale length slightly, hasn't it, and equally for all strings? The strings need compensation in different amounts due to having different thicknesses (and tensions?).
A bridge/tailpiece like on a Telecaster or Strat (for lack of words to describe them by type), allows the scale length to be altered for each string and secondly the height is adjustable for action, once the neck has a reasonably correct curvature/flatness (I forget what that's called - bias?).

If the action is too high, as worded elsewhere, either the string is bent more than desirable when depressed to the fingerboard, or with an archtop-type bridge separate from the tailpiece, the string takes an increasingly triangular shape the higher the action is...the straightest distance being between two points, the '2 logs' of the triangle make the string longer and it needs more tension to bring it to the correct pitch. (still thinking out loud here, OK, not claiming undeniable truths...). I can't clearly say what I think the effect of too-high action would be on the increasing sharpness, but obviously a slide needs higher action on a fretted instrument, and that is the solution...one doesn't need other design changes to play slide...

I have a hard time with the statement (I've read it myself) that the tension is greater at one part of the string than another...I've read it in the context of discussing string bending tension required for low and high tones on the same string....fretting (or fingering) notes at two different positions on the same string doesn't seem like it should change the string tension that significantly...is it that much harder to 'fret' the octave than the 5th? I would expect it to be if there is a large tension difference...well, actually a half step sharp is 2^12 or about 6% high in pitch so I would think only a 6% tension change when tuning...but the slight difference in action doesn't seem to be equal to the change in scale position.

If the intonation error gets worse the shorter the string is made, I think that's because the error is a smaller percentage of string length closer to the nut and a larger percentage higher up the neck.

Back to that question about open vs. octave and harmonic intonation. It better be right 'fretted' at the octave and open harmonic at the same position or there's no fixing it further up!

I may have my perspective skewed, but I'm really leaning toward a scale length error, like inadequate compensation. I think I understand how changing the nut position can affect compensation because the strings all do need some, but I think that's a tradeoff. I would think that nut repositioning compensation will give a different 'signature' to the intonation than bridge position compensation (at least to the extent that 'commercial' bridges have more flexibility, and I keep having this nagging fear that moving the nut changes the accuracy of the fret position (or markers in the absense of frets). An archtop bridge has offset fulcrum points for each string, and a 'Tele' type allows each to be adjustable. Do 'acoustic-type' bridges ever get mounted at a slight angle, not exactly perpendicular (90 degrees) to the strings to alter each string's length? This would be a proportional change depending on the angle, increasingly or decreasingly affecting adjacent strings depending which way the bridge was rotated. John Crocker's (I think) stove drip pan resonator has a floating bridge in a (round) block of wood in the center of the drip pan. He said it can be rotated for intonation...which I didn't 'get' initially...but I think it works as I've thought through visually (not out loud) above...

Here's an anal-retentive approach to intonation some guy shared with me - he works in a scientific field:

The practice of setting intonation at the octave by comparing the open or natural harmonic and the 'fretted' octave is a practical compromise...it cannot and does not correct intonation at all frets. This gets me thinking that a fretless instrument with the bridge positioned properly for octave intonation is FREE of intonation problems due to fret placement because there are no frets..hmm, that's a real no-brainer, isn't it. Then the player's ear's are responsible for all evil that results.

Anyway, back to his approach. He checks every fret (he buys assembled guitars, with frets) with a tuner, and notes where the intonation is worst for that particular string on that guitar. He then adjusts the bridge compensation for the worst fret, rather than assuming the 12th generally works for everything. Some are high and some are low. Compensating for the worst fretted intonation kind of 'splits' the errors so they are averaged...he called it a form of 'curve fitting'.

I hope this was at least interesting if not helpful, and not a waste of everyone's pixels :O)

Murray

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Permalink Reply by Crow on June 6, 2010 at 11:30am

@murray
wow

that took a while to read, and clearly theres a lot of thought put in to this

and while i appreciate the effort put in to your post, you are still talking to a bunch of guys who mostly just "put a stick on a box and play it" LOL.. what i enjoy the most about building these instruments is the simplicity. i'm very happy with my results without too much effort. i'll never be a proper luthier and the more i make simple instruments the more i am satisfied with them it's always awesome to see guys like you that really think farther in to it, it develops a greater insight in to the principles behind what we're doing, it helps us understand our results better.

i like your addition of the idea about "compensating for the worst fret", it reminds me of a tuning method i learned which accomplished the same thing on problematic guitars, i call it the "D" method, for the best results on a guitar without having to mess with the nut and bridge, etc...

the D method:
-tune the D string, open note, to a tuner
-tune all other strings, fretted to the D note on that string, to the open D string

this works well because each string is compensated, and when playing, each string is tuned to reach a "proper" pitch at a different place on the fretboard, and in this way, when playing up and down the neck, some strings are moving more "out" of tune, and the others are getting closer "in" tune.

it works much better than the standard "tune to the fifth fret (4th for B) method", because in this state, they're all effected by the 5th fret of the string before it in tuning, which builds a cumulative error from one string to the next, and by the time you get to the last string, the final note may be way off.

heh. sorry, i made a long post too.

but i figured your post deserved a decent response.

have a great day guys!!! (and try the D method sometime on a problematic 6 string "real guitar".. it may be magic for you!!)

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Permalink Reply by Murray on June 6, 2010 at 11:34am

...and you'll have six guitars done, and play them well, but I'll have parts for 12 but none built, and not be sure which end of the guitar goes in my mouth (used to play saxophones).

:O)

Muray

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Permalink Reply by Crow on June 6, 2010 at 12:54pm

@murray
LMFAO

the player sits down with his cigar box guitar, carefully whets his lips, and raises the neck to his mouth... thpppthhtpththtpppppTHTHTHTPPP!


hahah that would be quite funny!

i may have to remember that for my next show...LOL

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Permalink Reply by Wes "I'm Baaaaack" Yates on June 6, 2010 at 4:03pm

Well Murray, I can see your points, and to address all of them is unnecessary here, but here's one thing to consider--fret the octave (12th) and you see the force needed to fret the note is less than the force needed to fret at the first or second and so forth. Not too much different and I believe that is why the nut action is lower at the first few frets than is at the 12th-20nth fret. I believe the string tension between your finger at the lower frets and the nut is greater because of that extra bend/force needed to fret the note.

You could also be right in the scale vs fret calc. Tho I think Larry might have use the correct scale. I dunno. I still would check the bridge and nut.

-WY

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