older acoustic guitar intonation problem

[Arthur Sweeney]

Hello,

I’ve noticed that with my Brazos acoustic
guitar (model BA-50);

I tune the guitar as normal, using

a good chromatic tuner, but then

play a certain chord, and it sounds

a bit out of tune.

So, open strings tune fine, but

some fretted strings go sharp.

 Do you know how, when you check

the tuning by hitting the low E string

on the fifth fret, and then the string below

it open (A), they should sound the same (be in tune)?

Well, I will tune the guitar to perfect tune with the tuner,

then go check it with that trick, and some pairs of strings

will be right on, and others will not.

So, I am assuming the intonation is off, but how do you

alter that on an acoustic? Electrics have screws to turn, etc,

but acoustics seem unalterable.

Any idea?

Also, the action on the guitar is a bit high, not sure

if that is related or not.

The guitar is from the late 1980's. I do not believe

it is worth much, so I'd rather not sink alot of money

into it if possible, although I really do like the guitar.

Thank you,

-Arthur

[Mark McLean]

Yes, you do have an intonation problem.  If you play the harmonic note at the 12th and compare it to the fretted note at the 12th (on any string) I bet the fretted note is a bit sharp?  The high action is part of the issue because the distance that you need to push the string down in order to fret a note changes (shortens) the length of the string and alters (sharper) the pitch a little bit.  If you lower the action a bit it is likely to improve.  How high is the action, and how tall is the saddle?  Do you have room to drop the action?

The other way to adjust intonation is to alter the shape of the saddle so that the break point of the strings is slightly further towards the end of the guitar (just like with the adjustment of an electric - but not so convenient).  The reason why the saddle is sloped across the strings is to provide greater compensation to the bass strings than the treble ones.  I would sugest that you fix the action first and see how the intonation works out.  If it is still a problem the saddle will need some reshaping. 

Finally, why is the action high?  Is the bridge rotating or lifting, top bellying up, neck angle poor?  These are the usual problems of a cheap guitar reaching middle age. 

Mark

[Arthur Sweeney]

Hi

I played the harmonic on the 12th fret, low E string, and it

was in perfect tune. I then played the fretted 12th, low E, and

it was now sharp. You were correct.

 

[Arthur Sweeney]

Thanks Mark for the info. I cannot easily answer many of your questions. I need to go home tonight
and take a real good look at the guitar first. As for the high action, I would think shaving-down the saddle
is in order, as this is the usual quick fix, but it looks like there is not much saddle height left to do this.
The top of the guitar does not seem bowed, and the bridge is not lifting. I cannot recall if the neck is
straight, last time I checked, it seemed OK, but I am never sure when I look at necks. I have no luthier
training at all, so many times I am not even sure what to look for, or cannot easily notice when something
is amiss.

[Mike Kolb]

Arthur, it sounds like it might be a case of needing a neck reset. Try this....with the neck as straight as you can get it, lay a good straight-edge on the frets so that the end of the straight-edge just touches the bridge.  If the straight-edge intersects with the top of the bridge (not the saddle), then the problem likely lies elsewhere.  But if the straight-edge intersects considerably below the top of the bridge, then a neck reset is inevitable.  

If the guitar is a cheapie, it probably isn't worth the cost of the work. But Mark's right... first lower the action any way you can and see if the intonation improves. 

[Mark McLean]

Arthur - I will try to be gentle as I say this. 

Do what Mike said.  Put a straight edge along the frets and see if it points to the top of the bridge, or (likely to be the case) a position a bit south of there.  If the latter is the case you have a few options:

1.  Accept that this guitar will never again have playable action.  Set it up for slide playing and get a new one as your main guitar. 

2.  If the high action seems to be because the bridge is a bit elevated (increased arch in the top behind the bridge, dip in the top betwen the bridge and the soundhole) you can rescue it by installing a "Bridge Doctor".  See the Stewart McDonald site to buy one of these.  They have been the saviour of many a poor guitar.  

3.  If you really love this guitar and you want to give it a new lease on life, get a good luthier to do a neck reset.  Say goodbye to $500 bucks and enjoy your favourite guitar for another decade. 

Sorry, but this is the reality of life for the owners of 1980s cheap guitars. 

Mark

[Arthur Sweeney]

wow, a $500 repair for a $100 guitar, logic will not allow me to proceed.
Too bad too, I really like my old Brazos, you can't find them anywhere,
and it was my first guitar, so it has a small amount of sentimental value.
But, I cannot afford such a repair., Oh well, it will make good firewood I guess!
*sigh*

[Neil Fradenburgh]

Get thee to a Luthier...the advice you are getting here is the best of the best, however, no one can really give you an answer withouth having the guitar in hand. Don't go with the kindling option without having a professional look at it and give you a quote/estimate.

[Mark Pollock]

Very true, there may be a simpler issue, such as a needed truss rod adjustment. I also notice that too many guitars have saddles that don't actually match the radius of the fretboard, giving horrible action and playability. I'm sure this is an effect of buying a saddle off the rack without actually adjusting it to conform to the guitar.

 

You could always do the rather cheap alternative of cutting the heel and bolting it down again, the cheapo reset. It's not pretty, but effective. (I'm not finding instructions for this one, anybody?)

 

 

[Arthur Sweeney]

Bingo!

I took it to a local luthier, and he gave the truss rod a good turn,

and that was all it took. The action was high, caused by a bow in

the neck. The truss rod adjustment fixed the bow, and lowered the

action. Now with the action not crazy high like it was, the intonation

is correct. The action was so high, it was causing notes to go sharp

up the neck when fretted.

Thanks again to all for your advice.

Frets.net rules!!

 

[Mark Pollock]

Glad to hear it - nothing quite like that massive sigh of relief when it turns out that the worst case scenario is NOT what you are facing. Enjoy!

[Arthur Sweeney]

Well, I spoke too soon. Seems the luthier over-adjusted the neck a bit,

and while the action is low now, there is alot of fret buzz, so, I have to take

it back to him for further adjustment. At least he did not charge me.

So, the saga continues...

*sigh*

 

[Neil Fradenburgh]

Hmmm...since you were ready to trash it, so to speak, why not let it settle out a bit?  Leave it tuned to pitch and give it a rest (or play the heck out of it) and see where it lands in a few days.  i am not an expert, but I have a computer and a few guitars.