buzz

Action/Style/Fret-Buzz: The Other Side of the Coin

Action/Style/Fret-Buzz: The Other Side of the Coin

I’ve often hammered home the idea that players need to understand that a guitar needs to the setup for their style to prevent fret buzz. ‘As low as it can go’ isn’t as simple as it sounds and the player plays a massive part in whether a guitar buzzes.

But sometimes the guitar is to blame. And I should talk about that too…

Hum and Guitar String Ground

Hum and Guitar String Ground

So here's the problem: 

You’ve got your guitar plugged in. You’re not playing it and there’s a noise. A hum. It’s not terribly pleasant. 

Thing is, you touch the strings and it’s gone.

The response: It's ok. It's not a problem. That’s all as it should be. Guitars pick up interference and that comes out the amp as a hum. When you touch the strings, it's supposed to get quieter. 

Because, 'grounding'.

Bridge Ground and Mystery Ground Issues

It was a pretty noisy guitar.

There was a nasty hum that didn’t quieten down when I touched the strings. This is generally a good indicator that there’s grounding problem.

The quick test: Touching the metal of the jack on the (plugged in) cable quietened things. This means that somewhere inside the guitar, we’ve got a disconnected ground wire—if everything were working properly, there would be a signal path from the strings to the ground of the output jack.

A quick primer/reminder: The ground wires in a guitar help to ‘shield’ it from unwanted interference from the environment. The exposed metal parts of a guitar or bass are generally all wired to a common point. This includes the strings. Inside the guitar, there’s usually a wire from the bridge or tailpiece that runs to ground.

When you touch the strings (which you would normally do when you’re playing), you ground yourself through the guitar’s wiring and so you cease being a big meat-antenna, picking up interference, which is then picked up by your pickups.

Because this guitar quietened when I touched the output jack but not the strings, I knew that the path to ground had been interrupted somewhere.

Fixing the Bridge Ground

A quick look inside revealed what seemed to be the problem (more in a minute). I could see a wire from the back of a pot (common ground point) disappearing into a hole that pointed towards the guitar tailpiece stud. A gentle tug on this gave no resistance, however, and the wire pulled right out.

Problem found. Have to run a new ground wire to that stud.

Removing the stud bushing from the body isn't too much hassle (but be careful if you ever have to do this yourself). I fished in a new wire, stripped it back so it contacted the metal of the stud-bushing and reinserted the bushing. Then, I soldered the other end to the ground point on the back of the pot.

A quick check with my continuity tester showed that all was well—good connection between the bushing and ground—so I strung up and plugged in and…

Exactly the same problem.

What the heck? I was all set to treat myself to a nice cup of tea. What’s going on?

I pulled out my multi meter again and, sure enough there was no ‘continuity’ between the strings and ground (that ‘I’ on the meter indicates there is—for all intents and purposes—Infinite resistance).

NOTE: In case you’d like some basics on conductivity and resistance.

No 'path' between the strings and the ground point

Fixing the Ground ’Continuity’ Problem

I had a suspicion of the issue so I decided to work my way back with the meter.

The internals all looked fine. Perfect continuity between the output jack’s ground and the pot with the bridge ground wire. From outside, I could just probe the bushing and that was fine too.

Then the trail went dead. Suspicions growing.

This particular guitar has a black powder-coating finish on the metal hardware. I have a feeling that this coating is preventing a good ‘connection’ between the metal parts. Check on the conductivity/resistance article for more on this. Without a good connection, there is no ‘signal path’ from the strings to ground.

Remove the strings again. Time for some ‘scraping’.

What I’m trying to do is to get a sound, ‘metal-to-metal’ connection for the bushing, stud, tailpiece and strings. Working in the parts that won’t show, I remove some of the powder coating. I use sandpaper or just scrape if it’s easier.

I want to see some shiny metal on the threads of the stud and the internal ‘post’ that holds the tailpiece. Same on the slot in the tailpiece (you can see the difference in the photos below)

Removing coating from the tailpiece stud threads and post

The post recess is coated too. It's gotta go.

The coating is cleared and bare metal is exposed. Great.

Lastly, and most fiddly, I scraped a little coating off the holes where the string ball-ends contact the tailpiece.

String things up again and check with the meter… 0.00Ω. That means there’s a clear path with no resistance from strings to ground.

All good. No resistance means a perfect path to ground from the strings.

Plugging in reveals a much quieter guitar. Splendid. 

Repairing Truss Rod Rattle

This Music Man fretless has a nasty rattle. It rears its head on a number of notes/positions around the board. This particular rattle isn't to do with the string buzzing off the frets (or the board in this case). Here, the rattle is caused by the truss rod itself vibrating. 

Inside the neck, there's a channel routed in the wood. The truss rod sits in that channel and, usually all is well. Sometimes, though, there's a small gap—a little play in the tolerances that allows the rod a space to move. That can occasionally lead to a rattling truss rod. 

In some cases, simply 'snugging' the truss rod a little more tight is enough to sort things out. Not always, though. 

Now, it's worth mentioning that this can be a very tricky problem to resolve. How to proceed is sometimes not clear and, what's discussed here isn't necessarily the solution to all buzzing truss rods. Experience can give you a head-start in making the right call so, if you're in any doubt, seek out some trusted advice. 

The Solution

'Solution'. Get it? I make a glue solution. Get it? Oh, never mind. 

In this case, what I'm trying to do is to fill some of the gaps around the truss rod with something other than air. I've watered down some Titebond glue. Watering it down not only makes it flow more easily (there'd be no chance of getting it where I want it at its usual viscosity), but dilutes its strength too—we definitely don't want a glued truss rod. 

The diluted glue will, hopefully, flow down the channel and fill some of those spaces. When it cures, it won't be strong enough to actually 'glue' the rod to the neck but will remain in place (albeit probably in a crushed form once the rod is tightened) and continue to fill the gaps. 

Rear Access

If this was a fretted instrument, there's a good chance I'd have worked from the fingerboard side—maybe removing a fret or a position marker to drill a hole for access. This would be neater and would let me get closer to the centre of the channel (where I want to be). 

Here, though, I've got an unadorned, fretless, fingerboard. Gotta go around the back. 

I drilled an access hole at the heel, carefully, until I hit the rod. As an aside, I've spotted that there's already a hole closer to the end of the neck. I chose to ignore it because it meant even farther for my glue to flow and because it was a bit close to the adjustment, 'business end' (no sense risking gumming anything up). 

The diluted glue is, slowly, so very slowly, dribbled in. I'm not planning on filling up the entire channel here, I just want to make sure to get a reasonable amount of glue around the rod (primarily at the middle section). I'm obviously holding the neck vertically to allow gravity lend a hand and I've slackened off the rod into a neutral position before starting.

Plugging the hole

Plugging the hole

When I think I've got enough, I stop. Then I lay the neck flat on its back. The hope (and when you're working blind like this, there's a good portion of hope involved) is that the glue will pool and cure as planned.

Since the glue in the channel isn't exposed to a lot of air, I play it safe and leave it a few days before working on this again. I want to make sure all of that glue has cured. A rap on the neck seems promising so I reassemble the bass and have a go. 

Success. Plug that hole and we're done. 

I'm off for a celebratory cuppa.  ;-)

NOTE: It's worth stating that, this particular solution can be tricky. You don't want to glue the truss rod into place and you don't want to just inject 'mostly-water'. The consistency of the diluted glue is important. You need a Goldilocks zone—not too thick or too thin. Likewise, if it's not successful first time, earlier glue might block the way for a second attempt. If you're not sure, take the repair to someone who is. 

Fret Buzz: Is it REALLY a Bad Thing?

I need to talk about fret buzz. This is a bit difficult for a repair guy to do because, as I get into this, it can sound like I’m trying to dodge responsibility for shoddy work. That’s not the case—I actually feel pretty strongly about not doing that. The thing is though, it’s important for a player to be realistic about his or her needs and expectations when it comes to setup. Nowhere is this more of an issue than with fret buzz.

Here's a bold, but true, statement: The guitar is an imperfect instrument.

In order to generate noise it’s necessary to make a string vibrate up and down. Unless you’re fingering at the very end of the neck, under that vibrating string is a length of fingerboard, usually with a number of frets installed in it. It’s not like a harp, where you pluck a string and it rings beautifully and unimpeded—your guitar or bass has a bunch of wood and metal just dying to interfere with that vibrating sting.

Careful fret levelling and good setup can get an instrument playing cleanly. However, bear in mind that your playing style and technique, and the choices you make around action and strings, will have a major bearing on how cleanly that guitar plays.

Fret buzz MIGHT be a problem. Or it might not. Think critically and be consider the compromises either way.

Fret buzz MIGHT be a problem. Or it might not. Think critically and be consider the compromises either way.

Is buzz bad?

Yes.

Most of the time.

However, if you’ve got a low action on your electric guitar or bass and you tell me you can hear a buzz when you play it unamplified, I’m going to ask you if that buzz can be heard when you play it through the amp, in a normal setting.

Buzzes on electric instruments that can’t be heard through the amp are often the price of that low action you like. In an ideal world, it wouldn’t be there but it’s not an ideal world (see note above on harps). If you want to play your electric guitar unamplified, it might need to be set up differently. Remember that there’s a reason most acoustic instruments are not set up with actions as low as their electric cousins.

Consider action

Is your action appropriate for your style of playing? We’ve talked about this before—if you’re a hard player, you can’t expect to play with the same action as a really light picker. Bigger string vibrations need more room to move and a higher action is the answer.

Consider string gauge

Super light stings wobble about more on a particular instrument. A heavier gauge might give you a cleaner result. Playing the heaviest strings you’re comfortable with is always good advice.

The elephant in the room: technique

Ooooh. This is the difficult bit.

I’m (very, very) far from being the best player in the world. However, I’ve worked on these things enough that, at least, I’m pretty good when it comes to fingering/fretting notes cleanly. There have been times when I’ll play a guitar that someone’s brought in for buzzing problems and it’ll play just fine.

That’s tricky. Nobody likes to think something might be their fault (I certainly don’t) and nobody wants to be the guy to tell someone that it’s their fault (I certainly don’t). But sometimes it is.

Fingering position and pressure are likely culprits. You want to be right behind the fret with a firm enough pressure to ensure good string-contact with the fret. If chords are buzzing, play the same notes individually—is the buzz still there? Sorry that I’m teaching grandmas to suck eggs here. However, if someone else can cleanly play your buzzing guitar, you might need to consider adjusting your technique or your expectations for your setup.

On to Hardware…

Of course, there are hardware problems that can cause fret buzz. A couple of the more common:

Hardware issues: High/Low Frets

For a guitar to play cleanly, each fret should be neither higher or lower than its neighbours. If a fret is high, playing notes behind it may cause the string to vibrate off that fret. If you’ve a low fret, then the fret directly in front of it is (relatively speaking) a high fret.

High or low frets can be caused by poor fret installation and levelling. It’s also possible for frets to loosen and to sneak up out of the fretboard over time.

If your guitar buzzes in one or a few small areas but plays cleanly elsewhere, high or low frets may be the reason. For instance, if you’re playing each note up the board and all play cleanly until, say, 9th fret. The 10th has a little buzz and the 11th sounds awful but the 12th plays cleanly again. You might have a high 12th fret.

It’s not always so cut and dry as this, of course, and it can be useful to use a short ruler to try ‘rock’ across a few frets. You can buy a ‘fret rocker’ (which has a number of different-length sides to fit across differently spaced frets) from Stew Mac or eBay, or you can cut a 6" steel rule into different lengths. If you span three frets and your tool ‘rocks’, one of those frets is higher or lower than its pals.

Hardware issues: Nut Slots

If you get a buzz when you play an open string, there’s a good chance the string slot in the nut is too low. It’s also possible the you need a little more relief or your first fret is too high. Odds are good it’s the nut, though.

Hardware Issues: Relief

Incorrectly set relief (the bow your neck pulls into under string tension) can lead to fret buzz.

At a high level, too much relief can be a cause of some buzz higher up the neck. Too little relief might cause some buzz all over if you don't play lightly. A back-bowed neck will generally buzz in the lower positions and play more cleanly higher up.

This is all very general. If you haven’t downloaded your copy of Truss Rods Made Easy, pop off and do so. You’ll find more information on relief issues in there.

Hardware Issues: Humps and Bumps

The neck itself can sometimes be less than level. Humps and warps can happen. The result is that some sections are higher than their neighbours and that has to be addressed. A fret level or fingerboard level/refret is often the answer.

The bottom line

Potential hardware issues aside, a good setup for you may well be the result of some compromises. You might have to play with a lighter touch if you want a low action. Or, you might need to play a higher action to accommodate your style. You might need to live with some unamplified buzz.

Before you ask your repair person to lower your action, really, really think about it.

The most perfect, flawless, fret-job in the world will buzz if the setup isn’t right for the player’s style and technique. Be realistic about what’s right for you and don’t worry too much about unamplified buzz.

Or buy a harp.

Repairing Loose Acoustic Guitar Braces

Visible gap on loose acoustic guitar brace

Glued inside the top and back of your acoustic guitar are braces. These are wooden support beams* that provide strength to what are, otherwise, relatively thin pieces of wood. 

Sometimes a brace can become loose. This could be because the guitar gets a knock but, often, some or all of the glue can just fail for a variety of reasons. 

A loose brace can be a pain. If part of the guitar isn't properly supported, it can pull and warp in unpleasant ways. That's generally not good. In addition, one symptom of a loose brace (and frequently the one that leads to its being discovered) is a nasty buzz or even a rattle when some or all notes are played. Often this buzz is located around a certain note (a tone or so either side) as the loose brace vibrates in sympathy. 

These can be an incredibly frustrating thing to track down. Sometimes you'll get lucky and be able to see the gap between brace and top/back (like in the photo at the top—the shadow beneath is clear) but, more often, you'll end up, up to your elbow in the sound-hole, poking at joints with a feeler gauge, trying to find a tiny gap. It's a real pain. 

When it's found, the gap should be cleaned and the old (failed) glue removed. Then, fresh glue is worked underneath the brace and the repair is clamped up to cure. This sounds straightforward until you try doing it, at the limit of your reach, blind (or, with an obscured reflected image in an inspection mirror).

Loose acoustic guitar brace

Find loose guitar brace

Not so with this one, though. These are back braces and they're relatively easy to get at. This particular guitar did actually get a knock and has had a previous repair for a back/side separation. I can't be certain that these braces were knocked loose at that time but it seems likely. Maybe not, though—benefit of the doubt for the previous repairer.

You can clearly see the feeler gauge poking under the braces in the photos. The blue tape is something I've put in, by the way. It keeps the mess down when working glue under the brace. 

Once there's a good smearing of glue in there (and it needs to be worked well under to get a good joint), a bit of a wipe up, and then it's clamped (see below). The little scissor-jack thing is a god-send for these jobs—it gives decent clamping pressure and I can wind it up from outside the sound-hole. 

On this particular instrument, this has to be repeated a few times as I found four loose ends. But not any more more. All re-glued and sorted. 

Glueing and clamping loose back brace on acoustic guitar

*I think 'beam' is the correct structural term for guitar braces but any engineers can feel free to correct me. Beam tends to make most people think of massive steel joists, however, while guitar bracing tends to be a little smaller. And wooden.