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Kenny202

Yamaha CPX 900 high action

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Bought a Yamaha CPX900 yesterday. Got it home and thought pretty easy to lower the action. I shaved the bottom of the saddle a bit. Tightened up the truss rod a bit and to me anyway still seems a bit high. Mind you I like a very low action on an acoustic similar to an electric. Played around with it all day and best I could get it. I can't take any more off the saddle or the strings will be going over the bridge wood. There is no noticeable belly bulge but I put a straight edge across the top of the guitar behind the bridge and it is not 100% flat. The bridge isn't tilted forward or anything like it is under strain. Looks flat on the top of the guitar. Just sort of raised slightly where the bridge sits. I guess you would fit a coin under each side of the straight edge at the edge of the guitar. I took it to a local luthier and he said this model guitar is not meant to have a 100% flat top and he thought the action was pretty normal. He put a light and mirror in the sound hole and said bracing was sound. I reckon there is about 3mm at the 12th fret on the low E string. The lowest I can get the action is with the truss rod tightened so the neck is slightly concave believe it or not. I have 11-50 strings on it. I tried 10's but weren't a lot different. Come to think of it I have only ever had one acoustic guitar with a super low action in the past, an early Japanese Takamine. Was like silk to play. Neck so straight. About 1mm strings off the frets all the way up the neck and no buzz etc.

Am I being unrealistic. I know a better tone is probably achieved with a higher action but I wish I could lower it more. I have played around with the truss rod to lower as much as I can without buzzing and taken as much as I can off the saddle. I guess the Luthier should know however I am not 100% confident this guitar is meant to have a slight arch.

What do you guys think? Been doing my own set ups for years, mostly electrics but this one has me stumped.

 

 

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Posted (edited)

Yes, you are being unrealistic. The action of an acoustic guitars needs to be higher than on an electric guitar.

You say had an action of 1 mm on a previous guitar? - that's just silly.

 

Edited by garthman

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The few Takamines I've played had very stiff (laminated) tops and sounded pretty dead acoustically.    If you're planning to plug in, that's not a bad thing, and it will help take the top distortion out of the picture and perhaps allow you to get ultra-low action.

But, yeah, that top looks fine, and your action for a nice solid-tiop acoustic sounds great.    Too low, and it may start buzzing depending on weather conditions.   Thin real wood moves.

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First, it's normal for the top of an acoustic guitar to be domed. Don't worry about it. Second, the truss rod isn't for adjusting action, whether it's on an acoustic or an electric. The truss rod sets relief, the curvature of the neck. Put a capo at the first fret and hold one of the E strings down at the neck/body joint. Slide a feeler gauge between the string and the 7th fret. There should be a gap of 0.005" or a tad more. If there's significantly less gap, loosen the truss rod; if there's quite a bit more, which is unlikely, tighten it. Adjust the truss rod until you get the correct gap and then leave it alone. Action is adjusted at the saddle. There's one more possibility. Take a straightedge and lay it along the frets on edge. It should just hit the top of the bridge. If it falls much below the top, your guitar needs a "neck reset," which is expensive and really not worth it on a cheap guitar.

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Kenny, I just wrote a rather long article on how to do basic setups over at another forum.   It would be worth your while to read thru it

https://www.tdpri.com/threads/basic-setup.952636/

I will add that my personal setup specs are pretty much the same for an acoustic and an electric, but other differences in the guitars make them play and feel differently.   In particular, most of us will play 9's or 10's on an electric and while an acoustic can be set up with 10's, for most guitars that is just too light.   10's have about 100 pounds of total tension, 12's (which are considered light for an acoustic) are around 165 pounds.   So even tho I will have the same relief, first and 12th fret actions those guitars will play very differently.   In addition, many electric players will tolerate the little bit of buzz that comes with super low action, an acoustic player won't.   We play electrics and acoustics differently (areas of the neck, bends).   And frequently acoustics have some issues going on at the body joint which need to be dealt with that you won't see on an electric.

So yes, you can set an acoustic with very low action if the frets are perfect but you still might not like what you have.    Read the posting.

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Have you done anything with the nut? Might be able to tease a bit of lowering there.

Very very rare to get action like electric. Maybe just consider acoustic as some sort of home gym for your fingers, get them stronger. Benefit is your electric playing will seem even more effortless, at least as far as fretting goes

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On 8/22/2019 at 4:58 PM, Freeman Keller said:

Kenny, I just wrote a rather long article on how to do basic setups over at another forum.   It would be worth your while to read thru it

https://www.tdpri.com/threads/basic-setup.952636/

 

Thanks for that Freeman.

I actually have a Yamaha CPX900 from the local high school that I'm cleaning up and re-stringing for the next semester coming up. I strung it with 13-56 (which I use on my acoustics) and am having the same issues.

I just picked up a second hand Epiphone DR90 (low end made in china) to have for my students who don't bring their own guitars. It has the same issue with 13-56 but it sounds much better with the heavier strings.

I will make use of your setup tips.

One question though... you mention that acoustics should have a "dome top." How do you determine whether it is the proper dome or a problem with the bridge being pulled up?

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24 minutes ago, onelife said:

Thanks for that Freeman.

I actually have a Yamaha CPX900 from the local high school that I'm cleaning up and re-stringing for the next semester coming up. I strung it with 13-56 (which I use on my acoustics) and am having the same issues.

I just picked up a second hand Epiphone DR90 (low end made in china) to have for my students who don't bring their own guitars. It has the same issue with 13-56 but it sounds much better with the heavier strings.

I will make use of your setup tips.

One question though... you mention that acoustics should have a "dome top." How do you determine whether it is the proper dome or a problem with the bridge being pulled up?

Since I also mentioned that acoustics should have a domed top I'm going to chime in. Freeman can always speak for himself. What you're describing with "the bridge being pulled up" (or at least what I think you're describing) is called "belly bulge." It's usually accompanied by a tilted bridge. If you look at the bridge from the side edge it should be level with the top of the guitar and the top of the dome should be pretty much under the bridge. On a guitar with "belly bulge," the bridge will be sitting at an angle on the "slope" of the dome and the top of the dome will be on the side of the bridge away from the neck.

Incidentally, a goodly number of guitars made today are designed for "light" (12-53 or so) strings, especially relatively inexpensive ones. Going up to 13's places extra stress on the guitar.

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7 minutes ago, DeepEnd said:

Since I also mentioned that acoustics should have a domed top I'm going to chime in. Freeman can always speak for himself. What you're describing with "the bridge being pulled up" (or at least what I think you're describing) is called "belly bulge." It's usually accompanied by a tilted bridge. If you look at the bridge from the side edge it should be level with the top of the guitar and the top of the dome should be pretty much under the bridge. On a guitar with "belly bulge," the bridge will be sitting at an angle on the "slope" of the dome and the top of the dome will be on the side of the bridge away from the neck.

Incidentally, a goodly number of guitars made today are designed for "light" (12-53 or so) strings, especially relatively inexpensive ones. Going up to 13's places extra stress on the guitar.

thanks for that - i see what you mean about the tilt

yeah, the string gauge thing - it's always been an issue for me   13-56 sounds so much better but does put a lot of strain on the structure - sometimes i'll tune down a full step or even a step and a half and use a capo just so i can use the bigger strings

my 'cheap' Yamaha F-310 handles 13-56  well and sounds fantastic for such an inexpensive guitar

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