Commando Jack Posted January 10, 2011 Share Posted January 10, 2011 Hi everyone, I've done a search on the forums and found nothing relating to this issue so here goes: I'm having issues with the intonation on my bass. The bass is set up so that it is perfectly in tune both when the open strings and 12th frets are played (which is usually sufficient when I'm setting my guitars up). However, when played around the middle frets, the notes are quite sharp. The worst offender is the 5th fret, where the strings are audibly out of tune and have had me running to the tuner between songs over the last couple of gigs. Now, the guitar is a cheapy korean P copy, but the neck has been replaced and I have seen this problem in a mate's more expensive bass that was professionally set up. Does anyone know the reason for this intonation problem and whether it can be fixed? This bass has served me well except for this and I'm not really ready to hear that I should buy another bass! Any thoughts? Quote Link to comment Share on other sites More sharing options...
Doddy Posted January 10, 2011 Share Posted January 10, 2011 Is the 12th fret harmonic the same as the 12th fret fretted? Quote Link to comment Share on other sites More sharing options...
LawrenceH Posted January 10, 2011 Share Posted January 10, 2011 [quote name='Doddy' post='1084906' date='Jan 10 2011, 09:56 PM']Is the 12th fret harmonic the same as the 12th fret fretted?[/quote] Either the fret positions are off due to poor QC, your playing is somehow bending the string around these frets or the action/truss rod are out of alignment. This last one is what I'd suggest! Check the neck relief and the action height at both bridge and nut. Quote Link to comment Share on other sites More sharing options...
Bloodaxe Posted January 11, 2011 Share Posted January 11, 2011 (edited) [quote name='Commando Jack' post='1084904' date='Jan 10 2011, 09:54 PM']...the neck has been replaced...[/quote] This is where I'd point the finger. Set the intonation on the 12th fret, then take a tape measure & check that the distance from the 12th fret to the centreline of the saddles is the same as (or very close to) the distance from the nut to the 12th fret. From what you've said, the odds are it won't be & you'll need to move the bridge until the two dimensions are equal. Edited January 11, 2011 by Bloodaxe Quote Link to comment Share on other sites More sharing options...
Grand Wazoo Posted January 11, 2011 Share Posted January 11, 2011 Have a good read through this link, by the time you've read it all you'll be an expert. [url="http://www.jerzydrozdbasses.com/akcndfr54jdhrei567/Ultimate_Guide_ver100.pdf"]http://www.jerzydrozdbasses.com/akcndfr54j...uide_ver100.pdf[/url] Quote Link to comment Share on other sites More sharing options...
Commando Jack Posted January 11, 2011 Author Share Posted January 11, 2011 Thanks for the replies folks, I'll get right on it and let you's know what it was! Quote Link to comment Share on other sites More sharing options...
MoonBassAlpha Posted January 11, 2011 Share Posted January 11, 2011 I'd look closely at how the nut is cut. If the string(s) are resting at the back of the nut not the fret side, you will be able to intonate at the octave correctly but the frets below will seem sharp, especially in the lower positions. Quote Link to comment Share on other sites More sharing options...
lettsguitars Posted January 11, 2011 Share Posted January 11, 2011 you're right as far as open and 12th. that should be enough for perfect intonation (although there is no such thing) if you're out in between you've got some serious issues. as someone said, check neck relief. too much relief (up bow) and you're intonation will be sharp. adjust the rod so you have a slight relief and adjust saddles so that from the 12th up is pretty much flat. no way of knowing without seeing the neck. Quote Link to comment Share on other sites More sharing options...
lettsguitars Posted January 11, 2011 Share Posted January 11, 2011 [quote name='MoonBassAlpha' post='1086237' date='Jan 11 2011, 11:23 PM']I'd look closely at how the nut is cut. If the string(s) are resting at the back of the nut not the fret side, you will be able to intonate at the octave correctly but the frets below will seem sharp, especially in the lower positions.[/quote] a totally valid observation. Quote Link to comment Share on other sites More sharing options...
Commando Jack Posted January 19, 2011 Author Share Posted January 19, 2011 Ok so over the weekend I sat down with the bass and checked a few things out on the bass: - The open, 12th fretted and 12th fret harmonic were all in perfect harmony with each other, but lower end frets were all sharp. - resetting the neck seemed to help a good bit, and reduced the sharpness at the 5th fret a good deal. However the tuning still wasn't quite there and still noticably sharp. - I took a close look at the nut and the two worst offenders (E and A) did have noticable gaps between the strings and the nut. The neck came with the nut pre-cut, so I think this might be where the final part of the problem lies. Needless to say the bass will be visiting a luthier this week! Thanks again for all the help and suggestions, and I'd add that Grand Wazoo's link was incredibly useful and should be made into a sticky if it hasn't already! Quote Link to comment Share on other sites More sharing options...
TheGreek Posted January 25, 2011 Share Posted January 25, 2011 [quote name='Grand Wazoo' post='1085155' date='Jan 11 2011, 08:55 AM']Have a good read through this link, by the time you've read it all you'll be an expert. [url="http://www.jerzydrozdbasses.com/akcndfr54jdhrei567/Ultimate_Guide_ver100.pdf"]http://www.jerzydrozdbasses.com/akcndfr54j...uide_ver100.pdf[/url][/quote] I had a quick look at this - impressive stuff - copied the PDF for future reference..hopefully i'll never need it... Quote Link to comment Share on other sites More sharing options...
redstriper Posted January 25, 2011 Share Posted January 25, 2011 [quote name='Bloodaxe' post='1085124' date='Jan 11 2011, 07:54 AM']This is where I'd point the finger. Set the intonation on the 12th fret, then take a tape measure & check that the distance from the 12th fret to the centreline of the saddles is the same as (or very close to) the distance from the nut to the 12th fret. From what you've said, the odds are it won't be & you'll need to move the bridge until the two dimensions are equal.[/quote] I tried this, but the saddles are all different distances from the 12th fret - which one should I use, or should I just take an average? Quote Link to comment Share on other sites More sharing options...
LawrenceH Posted January 25, 2011 Share Posted January 25, 2011 [quote name='redstriper' post='1102549' date='Jan 25 2011, 06:52 PM']I tried this, but the saddles are all different distances from the 12th fret - which one should I use, or should I just take an average?[/quote] Ignore this! The different string thicknesses etc mean that the effective vibrating length of each string varies, hence we have individual adjustable saddles in the first place. Do it by adjusting each saddle for matched tuning at the 12th fret versus open string, if that doesn't work then something else about the neck needs adjusting. Check out some of the links from this page if you're confused. Quote Link to comment Share on other sites More sharing options...
Bloodaxe Posted January 26, 2011 Share Posted January 26, 2011 [quote name='redstriper' post='1102549' date='Jan 25 2011, 06:52 PM']I tried this, but the saddles are all different distances from the 12th fret - which one should I use, or should I just take an average?[/quote] [quote name='LawrenceH' post='1102567' date='Jan 25 2011, 07:02 PM']Ignore this! The different string thicknesses etc mean that the effective vibrating length of each string varies, hence we have individual adjustable saddles in the first place. Do it by adjusting each saddle for matched tuning at the 12th fret versus open string, if that doesn't work then something else about the neck needs adjusting. Check out some of the links from this page if you're confused.[/quote] True, for a given value of true, Lawrence. I suggested this as [list=1] [*]The OP stated the neck had been replaced, and [*]It was a mistake I made as a rank noob about 25 years ago when trying to resurrect a bass my brother had built at college back in the early 70s. The original neck was banana'd so I bought a replacement from the local guit shop along with all the hardware. Fitted the neck, screwed the bridge on around some existing holes & voila! intonation nightmare! Turned out that the original neck had an oddball scale length against the replacement's 34". Cured by moving the bridge about 1/2". [/list] However... as subsequent posts strongly suggest the OP seems to have a nut that's been cut partially arse-about-face, I would ignore my own advice in this particular situation. FWIW, for checking the bridge location I'd draw a horizontal line through the bridge centre & locate that at the appropriate position (so 17" from fret 12 for a 34" scale). As the thicker strings tend to intonate behind this notional centreline & the thinner in front of it, there [i]should[/i] then be sufficient room for adjustment. Pete. Quote Link to comment Share on other sites More sharing options...
geoffbyrne Posted January 26, 2011 Share Posted January 26, 2011 You haven't put a 19 fret neck on a 20 fret body, have you? G. Quote Link to comment Share on other sites More sharing options...
iconic Posted January 27, 2011 Share Posted January 27, 2011 [quote name='Grand Wazoo' post='1085155' date='Jan 11 2011, 08:55 AM']Have a good read through this link, by the time you've read it all you'll be an expert. [url="http://www.jerzydrozdbasses.com/akcndfr54jdhrei567/Ultimate_Guide_ver100.pdf"]http://www.jerzydrozdbasses.com/akcndfr54j...uide_ver100.pdf[/url][/quote] brilliant guide thanks Quote Link to comment Share on other sites More sharing options...
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