|
Post by Matt on Dec 18, 2010 0:21:54 GMT
Hi all,
I recently slightly lowered adjusting the truss rod on my acoustic guitar (gently, 1/4 turn at a time, settled for 2 1/4 turns in the end). It's been a couple of weeks and so I can't say I noticed this immediately, but I've now noticed that the intonation is slightly out across all the strings, they're sharp at the 12th fret. It's not by a huge amount, but it's quite noticable when I fret around the 10th fret.
Could this be a consequence of the truss rod adjustment, and is there anything I can do other than try turning the truss rod back? The only other thing I can think of is that the strings are maybe couple of months old, and it's been brought to a warm house from a persistently cold one. I'm also playing in open G, and presumably the guitar was set up for standard tuning (and I've messed with the action, as I said) Is it time for me to surrender it to a professional?
Cheers
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Dec 18, 2010 8:10:48 GMT
Altering the relief on the neck by tweaking the trussrod shouldn't affect the intonation. If you have significantly lowered the action, then I'd expect this to actually make the guitar play slightly flat if anything, as the strings will be bent less when fretting at the top of the fretboard.
By using a dropped tuning, the strings will be at a lower tension and may be more prone to being pulled sharp when fretting up at the top of the fretboard.
In theory, the change in the temperature and humidity could have had some overall effect on the guitar in terms of expansion/contraction and subsequent change in the relationship of nut to bridge and frets, , but this isn't something I've had any experience of...maybe other people will chip in on this point.
It's difficult to be sure what's caused this, as you've done 3 things - altered the tuning, changed the environment where the guitar is being kept, and tweaked the trussrod. Whatever you do in future, just try and change one thing at at time and check to see if it's had any effect, then you've got a fighting chance of determining what's causing the problem, or at least reverting to the previous set-up.
Lastly, and I know this will sound daft, but don't dismiss the possibility that you really weren't aware of the imperfect intonation before you fiddled with it, and that you've actually become super-critical after the adjustment. If you are really unhappy with it, I'd go back a step at a time to see if I could sort it - put it back into standard tuning, if that doesn't do anything, then put the trussrod back to how it was and check again.
|
|
|
Post by pete1951 on Dec 18, 2010 10:54:41 GMT
If it played in tune with these same strings on and with the action a little higher, it may well be the strings. Put on one new string and check again. strings get worn by playing and rust will build up unevenly, changing intonation
|
|
|
Post by Matt on Dec 29, 2010 0:15:18 GMT
Hi,
This is a bit of a change of topic, but still relates to my truss rod adjustment.
Has anyone else noticed cracks in the finish on the neck of their guitar after truss rod adjustment? I've got a small point crack below the 13th fret, about the same size as the fret markers on the side of the fretboard, and then a crack running down the bottom of the edge of the fretboard between the 1st and 3rd frets, all on the top side.
I'm not particularly bothered, as guitars always pick up scars unless they're unused in a cabinet (got a few dings pretty much straight off on the shoulder under the neck from poorly coordinated sliding), but I am curious to know if this is common, and I should warn anyone I ever suggest a truss rod adjustment to!
|
|
|
Post by robn on Dec 29, 2010 17:33:18 GMT
2 1/4 turns on a truss rod to dial out relief is quite a lot? It must have been like a banana before you started Ideally, you wouldn't use the truss rod to set the action on a guitar. There is a perfect truss rod setting for each guitar, normally just a shade of relief in the neck, that gives the best playability for the musicians playing style and the string tension. The truss rod is adjustable to cope with changes in string gauges (or tunings) but generally most of us will never need to touch the truss rod in our guitars. Occasionally, the rod has not been set correctly at the time of purchase and the neck is slowly pulled into a bow. Once the relief in the neck has been set by the truss rod, then the action height should be set by cutting the nut, then the saddle. It is very difficult to set the truss rod simply by eye due to the perspective of looking down a neck. Intonation problems - start by changing the strings. Cracks at fretboard to neck joint - I'd really have to see the guitar but it does sound like the truss rod is fighting to get out of the neck. As I said 2 1/2 turns would normally take a neck from a convex to a concave bow (although some double action truss rods go through a "slack" phase for a turn or so before working in the other direction) Robin
|
|
|
Post by Matt on Dec 30, 2010 0:33:20 GMT
The neck did have a visible forward bow before I started, I'll try and post some pictures tomorrow. The neck looks to my eye to be flat now. The intonation also seems to have improved with a fresh set of strings. If it looks to you like the truss rod is trying to escape I think I'll probably gently ease it back slightly to relieve any unnecessary strain I've put on it
|
|
|
Post by robn on Dec 30, 2010 9:05:06 GMT
As a rough rule of thumb for acoustic guitars (you may want electrics a little straighter than this) capo at the first fret in standard tuning then fret each string at the body joint (12th or 14th fret). There should be just a very small gap under the strings from frets 5 to 9. If you are getting buzzes when playing at frets 2 to 5 then the neck is too flat.
If you still have a little relief in the neck then I'm sure that your guitar will be fine as you will have it in the position that the truss rod was designed to hold.
If the action still feels too stiff when there is some relief in the neck then the culprit is most likely the nut slots. The bridge is the last port of call as it actually has the least effect on the feel of the guitar.
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Dec 30, 2010 11:57:02 GMT
Can you clarify whether you mean 2 times 1/4 turn or 2 and a 1.4 turns
|
|
|
Post by Matt on Dec 30, 2010 12:04:35 GMT
1/4 turn, twice over, so a 1/2 turn in total, rather than 9 x 1/4 turn! Looking back I probably should've been more clear, thanks for pointing that out.
Edit: I tried to write this in the post below but it didn't come out (maybe hidden behind pictures?). Robin, I did the checks you suggested, no buzzes and there were small gaps above the frets where you said there should be with the 1st fret capoed etc.
|
|
|
Post by Matt on Dec 30, 2010 12:29:51 GMT
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Dec 30, 2010 14:01:18 GMT
I've never ever had any cracks after adjusting a trussrod - that looks the trussrod may be trying to force the fretboard off the neck. How much resistance was there when you tightened the trussrod? Did you do the adjustment with the strings removed or slacked right off? I know it can be difficult to gauge how much force you are applying, but I'm always very cautious about this for fear of stripping the rod or causing other damage. A 1/2 turn doesn't sound much at all, but if it was already exerting a lot of force it might have been enough to damage the neck.
Did you put a straight edge down the neck before you started and to see what state it was in, and during the process to see what effect you were having?
|
|
|
Post by Matt on Dec 30, 2010 14:14:13 GMT
The truss rod was reasonably stiff, but didn't require forcing. I left the strings on and tuned up in open G. I didn't use a straight edge to check, just did it by eye as I only wanted to make a maximum of a 1/2 turn, with the view that if this didn't adjust it to my liking I'd take it to someone better qualified. There was a visible forward bow on the neck before I made the adjustment, almost like a slight bend around the 10th/12th fret. The difference in playability is now that it's very nice for fingerpicking, and a touch low for sliding, which is ideal as I have a Lightning on the way soon (hopefully!) for slide business.
This may be me being hopeful/optimistic, but i looks to me like the crack is only in the finish, and is above where the fretboard is actually glued to the neck, hopefully suggesting that it's not separating. I wonder if it's possible that a slight change in the curavture of the beck has caused a shear force in the finish, causing the crack that way? There are no marks on the other side of the fretboard.
|
|
|
Post by gaucho on Dec 30, 2010 14:31:19 GMT
What guitar is that? Is it Parlor sized?
|
|
|
Post by Matt on Dec 30, 2010 14:43:44 GMT
It's a Recording King ROS-16 (specs here: www.recordingking.com/guitars_ros16.html ), they describe it as a OOO-shape body, which I would count as a parlous guitar, although someone may correct me! It's very nice, and feels well built. Hope I've not knackered it by tinkering! I'd save up and buy another if it was stolen or broken.
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Dec 30, 2010 17:38:15 GMT
It's all a bit late now, but the trussrod isn't really designed to adjust the action, but rather to counteract the pull of the strings and fine-tune the relief in the neck to stop fret buzzes. Adjusting the trussrod is part of setting-up a guitar, but there's more to getting the action just right than cranking the trussrod...that's why I asked about the straight-edge as it might have given a better indication of what the problem was. It does sound a bit strange that you say it looked like it was bending forward around the 10/12th fret, as usually a neck that needs a bit of relief taking out of it usually displays a fairly even gentle curve along its length rather than at one point in particular. Bends in the neck where it joins the body are typical of a guitar that needs a neck re-set, so this sounds a bit odd on a new guitar.
Looks like that crack in the lacquer may well caused by the fretboard being pushed up by the trussrod: modern glues are stronger than the wood itself, so it's quite possible to actually split the timber before the glue joint gives up. I reckon it's unlikely that the lacquer would crack like that just by general deflection of the neck, it looks like it's had some localised trauma of some sort. It's a bit strange it happening at that point though, as I wouldn't expect there to be much upward force exerted by the rod there, but I don't know how the truss rod on this guitar is installed or anchored.
|
|