Cheers Friends,
I finished my building on my first 4 string cigar box guitar :D
Really glad about the sound, I used Humbucker and Piezos (thanks to wayfinder and david l.) see this discussion (http://www.cigarboxnation.com/forum/topics/soldering-2-humbucker-2-piezo-2-potis-and-one-switch).
Now i plugged in my first one and enjoyed the sound, but first of all i heard that the intonation was totally wrong. I tuned my 4 strings to G D G H (open G).. So.. first of all I thought let's check (again!) the scale length and the frets.. all good! (just some mm, but at all it's pretty close.. the scale is 60cm, 12th fret is by 30cm. Okay, so .. let's check the bridge position and adjustment.. okay all good.. 60cm at all from nut to bridge.. hm.. searched on cigarboxnation and found this discussion 'bout the same topic:
Looked at my string height and .. here we go.. the first string height was bout 4mm (nut) to 14mm (bridge). So i brought the string to bout 2mm and at the back bout 10mm.. just a little bit better.. but not good at all. I decided to set it up to 4mm and 14mm and play it as a bottleneck, for the first day, because it sound pretty good and it makes fun, too.
But I'm really into changing the guitar, or know where my fault was to avoid it on the next one and use this one as a bottleneck.
I think that one problem could be! First of all I wanted to set the humbuckers and the bridge directly on my neck (bout 5mm under the fretboard).. now i did it on top of my cigar box. It seemed to be better, instead of cutting holes in the top for the cover of the humbucker and the bridge. Now after all, it makes sense because the string are bout 5-7mm higher on the side of the bridge, so this could cause the intonation problems.
Do you got some other things to check ? Do you thing the 5-7mm can cause this problem? Would you recommend to bring the bridge and the covers of the humbucker on top of my neck wood?
Here are some pictures for a better understanding:
Thanks in advance.
Regards Greg
Replies
Picture #1 and #2 look like the saddles are all in a line and at the edge of the plate. So I assume your fretted notes go sharp as you go up the fingerboard.
Sorry Shawn has it backwards, if the open string is in tune and the 12th fret is sharp, turn the end-screw clockwise as you look at it, (screw it in, righty-tighty) to move the saddle away from the nut. this increases the distance from the 12th fret to the saddle and makes it less sharp.
Retune the open string, test the 12th fret, and if still sharp, turn it in some more....repeat until open and 12th are both in tune.
when all the strings and 12th frets are in tune, there should be an obvious slant to the saddle positions..
Sean makes a very good point, a pic side on will say a lot more, especially with a plain background, your neck pup must be touching or near touching the strings by the photo, if so it might be an issue.
Enclosed some pictures for you. If you need some more, or measurements please tell me.
Thank u :)
Try some simple things.
Capo on the first fret, check the intonation. A capo there will basically isolate any problems caused by nut distance to fret 1. So take that bit out of the problem and have a check.
Play a middle note harmonic while the capo is on and do a comparison with that fret note. It's often wize to fix bridge compensation this way as you are setting intonation for the fretboard. Get this sweet and it will highlight any nut problems when you remove the capo and recheck full string harmonic intonation. String height plays a huge part in this so bring the height down before you set anything perminant.
Bridge compensation is very dependant on string thickness and if it is wound or not and how high the action is. So the slant people put on the bridge is individualistic to that guitar and string sizes. It has to be heard, not measured.
Looking at your photos I think your strings are sitting too high. When you press the string down it tightens it and raises the note slightly. You did say it was set up for slide just now so this might not be the problem after you lower the strings.
You can't really tell for sure from photos but I would hazard that string height coupled with your nut being slightly too far away from fret 1 will both play hazzards when you set bridge intonation. Do the capo thing.
Thank you Fomhorach, i think you're right! I have to work on the height of the strings, as well as 1-2 milimeters on the first fret. Does it really make such a big difference because of 1-2 milimeters?
The capo thing worked pretty good.. the tones get better, but not close enough. I don't know if i should take everything down (humbucker / bridge) or put a new fretboard on it. But if 1-2 milimeters change the notes that much, i have to find a way to make the fretboard precise.
Your strings look like the action in close to being right but without a full side shot it's hard to know.
also is the neck flush with the box if so that's one problem it should be about 1/4 higher than box or your strings will hit the pickups when you fret it in the upper range of the neck( lower towards the body).
Intonation is set by the saddle adjustment screw on the back side of the bridge.
First get the guitar tuned up to pitch then fret say the G string at the 12th fret.
If the note is flat screw the adjustment screw into the saddle to make the string leangth longer, and if it's sharp adjust the saddle towards the nut to make it shorter.
Do this to each string till they all play the same note open and fretted at the 12th fret.
You will need to retune the string each time an adjustment is made.
When they all ring true open and fretted you now have your guitar intonated. It will be worth the time it takes and just remember it's the final step to a great playing guitar.
Thank you Shawn, hopefully I'll can show you some more in the future.
yeah the neck flush is one problem.. maybe I can set down the mechanic and hope that it will be enough space with the box top. I adjusted the screws on the bridge, but for example i got a B on the low string, on fret 12 it was a C -20dB now it is a C -50dB, but still not a B :)
I think it could be the strings that are too high on the bridge and the nut. :/