Fixing action on acoustic bass

[Chipsonfire]

Hey all, I've recently come to notice that my G string's action is waaaaay too low, and it wasn't before. The problem is in the bridge/saddle area; it's set way too low there and causes buzzing on pretty much every note on the string. How can I fix this? I did a search but couldn't find any info on acoustics.

Btw, its a Dean Playmate 4 string, no cutaway, if that helps any. I've had it for a few months and only recently started noticing this.

[202dy]

Spring has sprung. It is likely that your ABG is responding to the change in the weather.

Before anyone can give you some advice that might be accurate more data is needed. At a minimum, if you could post measurements for string height at the twelfth fret bass and treble sides respectively and relief at the seventh fret. Refer to the sticky at the top of the page for instructions if you do not know how. This is the only way to obtain an accurate diagnosis when the instrument is present. It is the minimum needed to diagnose issues on the internet.

[Pilgrim]

The way I dealt with the opposite problem (action too high) was to slack the strings, remove the original saddle and measure it for width and height. I ordered a couple of blank saddles (Tusq material) from Stew-Mac and made a lower replacement, leaving the original alone.

You could probably do the same - just making the saddle a bit higher in the area where it's low. But I agree, make sure the saddle is the problem and that the bridge isn't pulling loose or the top of the instrument pushing down. You also need to check the neck to make sure it's set well.

[Chipsonfire]

Originally Posted by 202dy

Spring has sprung. It is likely that your ABG is responding to the change in the weather.

Before anyone can give you some advice that might be accurate more data is needed. At a minimum, if you could post measurements for string height at the twelfth fret bass and treble sides respectively and relief at the seventh fret. Refer to the sticky at the top of the page for instructions if you do not know how. This is the only way to obtain an accurate diagnosis when the instrument is present. It is the minimum needed to diagnose issues on the internet.

After checking string height and relief, it seems I do need a bit more relief in the neck (I have almost none). But that's still not the problem. The string height bass side is 1.5-2mm-ish (I don't have a very accurate way to measure) while treble side its less than 1mm. You can see at the bridge that it is much lower than the other strings. I'd take a pic but all I have is a camera phone I have to go to a meeting with my design group, but will be back a bit later.

[202dy]

Given that there is little relief, the estimated ratios of bass to treble string height seem to be acceptable. Adding some relief will probably take care of the problem. Loosen the truss rod, let it settle and post your findings.

BTW, go to the local cool hardware store that has been in business forever and has everything or the mega home store on the highway. Both will have a small, steel rule that is graduated it 64ths of a inch. They cost about six dollars. It is pretty much the standard tool used in luthiery shops across the USA. It is also good for cleaning dirt next to the frets. A set of feeler gauges is also a good investment to be used for measuring relief. And come in handy when you have to gap the spark plug for the lawnmower.

[Pilgrim]

If the curve on the saddle is good and all strings have similar clearance, a shim under the bridge might work. Auto machine shops can sell you brass shim stock in thicknesses of thousandths of an inch. Easy to cut to size with scissors and lay into the slot the saddle mounts in.

I haven't done this, but I know that various manufacturers do use shims under acoustic saddles, so I'm theorizing that extremely thin brass stock would work.

[Chipsonfire]

Originally Posted by 202dy

Given that there is little relief, the estimated ratios of bass to treble string height seem to be acceptable. Adding some relief will probably take care of the problem. Loosen the truss rod, let it settle and post your findings.

Originally Posted by Pilgrim

If the curve on the saddle is good and all strings have similar clearance, a shim under the bridge might work. Auto machine shops can sell you brass shim stock in thicknesses of thousandths of an inch. Easy to cut to size with scissors and lay into the slot the saddle mounts in.

Well, I need to loosen the truss rod anyway, so I'll go ahead and do that, but I don't think that is the problem. The curvature of the strings is not the same throughout. The E, A and D strings seem to be curving nicely together, but the G (when looking at it from the side down at the bridge) is well below them. The top of the G is almost underneath the bottom of the D in height.

[Chipsonfire]

So after messing with the truss rod, and looking closely at my bass, I think I found the problem. The neck itself is warped. For lack of a better term, its wavy. It has normal relief until about the 17th fret, where it bends out the other way. I hope that makes sense. The G string is also digging in the cheap plastic saddle on the bridge and seems like it has moved to the side a bit, which would help account for it being lower than the other strings. Any advice, or am I SOL?

[202dy]

Originally Posted by Chipsonfire

So after messing with the truss rod, and looking closely at my bass, I think I found the problem. The neck itself is warped. For lack of a better term, its wavy. It has normal relief until about the 17th fret, where it bends out the other way. I hope that makes sense. The G string is also digging in the cheap plastic saddle on the bridge and seems like it has moved to the side a bit, which would help account for it being lower than the other strings. Any advice, or am I SOL?

Anything can be fixed. You are not out of luck.

It does not necessarily sound like that there is a problem with the neck. It does not sound warped. Obviously the saddle should be replaced. Shimming an acoustic electric saddle can be difficult to accomplish well. However, if you desire an accurate diagnosis it is time for you to gather together the tools to take the measurements so that can happen.