Open G rattles like stink

[sarah thomas]

Sorry - wrong forum - been to the shop and cooked sausage and eggs while writing this. Please move to Double bass forum!

Please help. This is the story so far:

20 October. Bought Geraldine from the lovely Keith in Harrogate.
20 November (ish) off to the luthier for fingerboard shoot, new endpin, new bridge and new soundpost.
20 December. Home for Christmas!
6 January New strings

6 February. Open G string suddenly started buzzing like a chainsaw. Fifth stop G on D string has no buzz.

Now, she's an old bass, German flatback, probably not been played with any regularity for years. This is what I've tried so far, to no avail:
Shimmed nut under G string.
Restrung G string so it's well away from the sides of the pegbox.
Extended the endpin.
Tapped on the top of the bridge.
Checked the machine heads.
Put a sock in it - under the tailpiece and then under the tailpiece wire.
Tapped along the bass bar
Looked for open seams and cracks.

Is there anything else I can try before I take her back to the luthier?

Edited February 7, 2013 by sarah thomas

[Mr Bassman]

Try a different string?

[sarah thomas]

Have just tried a different string. Still buzzes. I have a feeling it's something to do with the bridge. Any ideas?

[Mr Bassman]

We can't have your G string buzzing Sarah!

Check the other 3 tuners, any play in the keys?

Have you got a pup attached, is there a cable touching the body or tailpiece?

Are you using a [url="http://www.thomann.de/gb/rdm_humitron_humidifier_bass.htm?gclid=CKzPu5OfpbUCFdLMtAodQBUAXA"]humidifier[/url]?

Does it buzz if you tune the g string to a different note? (don't go too high!)

Edited February 7, 2013 by Mr Bassman

[sarah thomas]

No discernible play in the other tuners. No cables, no pick-ups (she is very loud on her own!)
No humidifier.
Ahah! Tuning the string to a different note: buzzes at F sharp, and G. Buzzes less at G sharp and no buzz I can hear at A.

What next, oh wise one?

[ubassman]

Couple of things spring to mind that you could check and then see what your luthier makes of your observations :-

1/. Is the part of the bridge where the string passes over completely flat or are there chamfered edges in the wood each side of the string? If the flat bit is more than about 2- 3mm you can get buzzing where the string vibrates in contact with the too wide flat bit.

2/. Is the fingerboard original or new? The fact that one month after Geraldine arrived she had to be shot and now the problem is back again seems a bit peculiar? It may be that the quality of the grain of the fingerboard is not that good and is full of burrs and knots and wavy grain - if its a poor quality piece of wood it will need shooting again ...and again ....and maybe again.

This might be a useful bit of background reading [url="http://www.jeffbollbach.com/JB%20II/luthier_rant1.htm"]http://www.jeffbollb...thier_rant1.htm[/url] . The only solution might be to replace the fingerboard with a bit of quality wood.

3/. Check whether there is a dip in the fingerboard ( a good thing ). When you press the string flat against the very end of the fingerboard ( near the bridge) there should be a tapered gap between string and fingerboard ...starting at maybe 1mm at the nut ...with the gap under the string getting bigger and maximum at around the first octave harmonic position of maybe 2 / 3mm, and then tapering to nothing at the point where you are pushing down on the string . It should be a huge, wide , very flattened ' [b]\[size=1]/ [/size][/b]' shaped profile to the fingerboard . I tend to line up my eye with the string and fingerboard at octave position and the look left and then right at what going on.

4/. Put Geraldine on the kitchen table and have a look down the length of the neck by standing at the endpin end of the bass. Its usually possible when you get eye level peering down the string line to see any bumps and ridges. You can confirm with a straight edge ruler looking sideways on at the position and if you get a china graph pencil you can mark up any highspots .

Sounds like its going to be a Luthier job to correct the problem. Hope this helps in some way !

Edited February 10, 2013 by ubassman

[sarah thomas]

Thank you very much. I'll have a look at all those things this evening and report back.

[Mr Bassman]

Is the bridge seated properly?

Sometimes changing strings can pull the bridge towards the fingerboard, or a knock going through a door etc.

[ubassman]

[quote name='Mr Bassman' timestamp='1360499307' post='1971207']
Is the bridge seated properly?

Sometimes changing strings can pull the bridge towards the fingerboard, or a knock going through a door etc.
[/quote]

+1 on that - good call !!

Worth checking that the bridge isn't leaning forward or too far back as it will have the effect of lowering the action. What is too far forward or too far back? As a guide with the feet completely flat, the back face of bridge ( the side nearest the end pin ) should ideally be perpendicular to the top so as to transmit vibrations to the sound post and bass bar . The front face of the bridge will be have an angle at maybe 95 degrees to the top. If the feet don't look like they are flat then ease off your strings and straighten it up - I usually knock the bridge just a little back so that as the strings tighten they pull the bridge into position.

[sarah thomas]

Hello there. Back on the case of the mysterious rattle n buzz this morning -

First, I'd like to make it clear that I bought the bass knowing that some work was needed, and the original fingerboard shoot was part of that first batch of work. It just took me a month to find a double bass luthier who did work for jazzers, like wot I want to be. So -

The bridge seems to be seated properly. I tap it backwards a bit when changing strings too. The feet are so flat against the top that I can't slide a cigarette paper under them. The back of the bridge isn't perpendicular but is very nearly so. 92 degrees maybe. The front has more of an angle - about 95 degrees, as you say. One feels they should add up to 180, but hey.

The groove for the string on the bridge is 1.5 mm at most and everything seeems to fit snugly. In profile, the flat bit at the top of the bridge is about 3mm in the centre, moving out to 4mm at the edges. Maybe it needs rounding? Pete Tyler recommends no less than 4mm, otherwise the angle over the bridge is too sharp, causing the casing of the string to separate and fracture. This seems to be happening to the D string. Gah!

Interesting read on fingerboards. The fingerboard is allegedly pearwood which the luthier thought was okay, better than poor quality ebony at any rate. There is a tapered dip to the fingerboard and when I pressed the string down at the end of the fingerboard, the gap between the fingerboard and the string was widest just before the first octave harmonic, with a measurement of 3mm. So that seems okay! Really interesting to find out about too - thanks.

I thought I'd buy a chinagraph pencil. Crikey. It seems they are now called tile markers. The local hardware shop had never heard of them. B&Q supposedly had them in a tile pack but on closer examination of the pack, the tile markers had all disappeared. Topp Tiles finally came up with the goods. Then I realised that I don't really understand what I'm supposed to do with the marker.

I don't have a kitchen table. I have a drum kit where the table used to be. So Geraldine and I lay down on the floor together and I peered along her string length. I couldn't see any obvious lumps or bumps but I could make out the tapered dip quite nicely so thought I must be getting a fairly accurate impression. I laid her on her side and had another look. Still all looking good. Just to try, I marked the underside of the G string with the tile marker and played it, open and in various positions - noting the position. No marks on the fingerboard.

Anyway, this is all new to me and a real education. Many thanks to you both. I'll see Mike (luthier) on Thursday so hopefully all this information will help wtih a diagnosis.It's certainly helped me to learn a lot more about my bass. Maybe it's that bridge...

[Bilbo]

Sorry, mate, but I would have been at the luthier's by now.

[ubassman]

[quote name='sarah thomas' timestamp='1360312189' post='1968322']
Ahah! Tuning the string to a different note: buzzes at F sharp, and G. Buzzes less at G sharp and no buzz I can hear at A.

[/quote]

....interesting that when the G is tuned to an A the problem goes away . I think that this may be a tension issue ...are the replacement strings much lower tension than before? .

With a lower tension string the amplitude of vibration will be bigger especially around the octave position =buzzing on an open string. BTW what strings are you using - did you replace like for like or did you change brands?

Bit of background on amplitude [url="http://www.frudua.com/guitar_strings_tension.htm"]http://www.frudua.co...ngs_tension.htm[/url]

Edited February 11, 2013 by ubassman

[sarah thomas]

[quote name='Bilbo' timestamp='1360607589' post='1973303']
Sorry, mate, but I would have been at the luthier's by now.
[/quote]
Thursday's the first day we could both do.

[sarah thomas]

....interesting that when the G is tuned to an A the problem goes away . I think that this may be a tension issue ...are the replacement strings much lower tension than before? .

The strings she came with were steel. The A and D were Spirocore reds but I don't know what the others were. The G unravelled quite spectacularly when I took it off. They've been replaced with Innovations Ultra Blacks, so I don';t think they are that much lower.

[3below]

You have shimmed nut under the G. Try putting a small wad of aluminium foil or a small length of electric cable outer insulation split in the nut G string slot. Might indicate if it is the nut height. I experienced a similar bass guitar problem, nut height was the cause.

[sarah thomas]

Small wad of foil - still buzzing. Thanks for the suggestion, though.

[ubassman]

Am I correct in thinking that the buzzing occurs only on an open G string and its the sound of the string hitting the fingerboard rather than the buzz coming from the peg box, tailpiece or elsewhere?

All other things being unchanged ( from when your bass was working perfectly ), seems that the only two variables in the mix are the choice of new string ...or the fingerboard moving being out of shape. Have you got a thicker gauge string you could experiment with ? If a higher tension string solves the problem then you have two choices if you want to revert back to your Blacks :-

1/. Get a luthier to add more camber 'relief' to the fingerboard so that theres more clearance for your Blacks to vibrate. Will involve quite a lot of planing and refinishing.
2/. Raise the height of the strings with a new bridge or get a bridge adjuster fitted to your existing which gives you flexibility to tweak.

If Geraldine has been dormant for a good few years and is now much loved and in a centrally heated home perhaps the fingerboard needs to be re-shaped anyway . Theres a good chance that it may have warped and twisted a bit over the years and the original set up may be out.

Finally good luck and let us know how you get on !!

[Clarky]

To add to the above, both my DBs have developed a small amount of buzz on the board over the winter which I am sure is due to the temperature/humidity change. They both have relatively low tension strings (Spiro Weichs). Its not enough to annoy me and it will (I hope/assume) ease as the weather improves. I wouldn't mind betting this has played at least a small role in what you have encountered, Sarah

[ubassman]

[quote name='Clarky' timestamp='1360753528' post='1975764']
To add to the above, both my DBs have developed a small amount of buzz on the board over the winter which I am sure is due to the temperature/humidity change. They both have relatively low tension strings (Spiro Weichs). Its not enough to annoy me and it will (I hope/assume) ease as the weather improves. I wouldn't mind betting this has played at least a small role in what you have encountered, Sarah
[/quote]

The back on the DB shrinks in winter and can have the effect of pushing the fingerboard closer to the strings ( think squeezing a balloon) . So could just be a seasonal thing for you Sarah and if you want as low a string height as you can get, then a bridge adjuster is the way to go ( or an old fashioned solution which is a summer bridge and a winter bridge !!) . I would still just get a luthier to check that the fingerboard is spot on !

[sarah thomas]

Geraldine is now at the luthier's and the buzz on the open G string is being caused by an unstable repair by the 'f' hole nearest to the E string. She's having the top of the bridge rounded off a bit as well so it doesn't rub on the strings as much. Phew! Mystery solved and not terribly expensive. And to add to the gloriousness of this sunny day, I have received a tax rebate.

[ubassman]

[quote name='sarah thomas' timestamp='1360848359' post='1977310']
the buzz on the open G string is being caused by an unstable repair by the 'f' hole nearest to the E string.
[/quote]

...hopefully nothing to do with the Bass bar !! Glad that theres a firm diagnosis .

[sarah thomas]

All sorted now, with the bridge rounded off a little to stop the strings chafing - £40.

[Mr Bassman]

Was just thinking about your G string

See you've got it sorted

[sarah thomas]

Yep. All ready to get low down and dirty ...