Short Scale Action

[rustyg61]

How much difference should there be between the action at the 12th fret & at the 24th fret? I have a SCSD & my G string is .07 at the 12th fret & .09 at the 24th. This seems like a big jump from the 12th to the 24th. The neck is fairly straight with the right amount of relief, but the strings are noticeably higher as you get beyond the 12th fret. The action feels great on the 1st 12 frets with little to no string buzz. I have a 35 Schecter 5 string & the action is very close to the same at the 12th & 24th frets.

[bigredbass]

Rusty, I'm confused:  How are you measuring this?  Is this the numbers you're getting with the strings standing free, no pushing to the frets?
 
J o e y

[rustyg61]

I'm using the Stew Mac String Action Gauge -
 
http://www.stewmac.com/shop/Tools/Measuring_tools/String_Action_Gauge.html
 
The strings are free standing with me holding the bass in playing position, not pushing down on the strings.

[bigredbass]

OK.  I must be missing something.  
 
The string, floating above the fingerboard is .07 clearance in the middle of the neck, and .09 clearance over the last fret.  The string is a straight line and their is less clearance in the middle.  
 
Is it just me or is this saying it's higher in the middle of the fingerboard, not lower?  How is this straight with the right amount of relief?  I'm getting slower in my old age, but I swear it seems like if these numbers were reversed you'd be in the ball park.  It sounds like it's bowed up in the middle ever so slightly.  If you crank the truss rods a bit, you'll put relief into it and reverse what you'
re telling me, if I'm understanding these numbers correctly.
 
To really check this, capo at the first fret, hold thse strings against the fret where the neck meets the body, and check your clearance under the 9th or 10th fret.  Then we'll know what your relief really is.  Typically, with the strings free-standing in a playing position, I'd only check my clearance over the last fret for height/clearance.
 
J o e y

[rustyg61]

It is .070 at the 12th fret & .090 at the 24th fret. .090 is higher than .070, so my strings are noticeably higher off the fretboard as you get beyond the 12th fret. I am measuring from the bottom of the string to the fret. I have done the relief check with the capo & have about a medium pick thickness between the string & the fret in the middle of the neck. On my 5 string, I have a .070 on the G string at the 12th fret & at the 24th fret the action is only the thickness of the lines on the Stew Mac Gauge higher than .07. Here is a picture of my gauge so you can see what I'm talking about.
 

[lbpesq]

Joey:
 
I interpret this the opposite way as you do.  My perception is that his strings are closer to the fretboard in the middle of the neck,(12th fret), than at the end of the neck, (24th fret).  It seems to me this is exactly how it should be.
 
Bill, tgo

[rustyg61]

Bill, you are correct, my action is lower in the middle of the neck than at the end of the neck. My question is how much higher should it be at the end of the neck than in the middle because my 5 string 35 Scheckter is almost the same at both points on the neck.

[keith_h]

If your neck is straight or has a back bow I would expect to see what you are seeing. If you had some forward relief I would expect the middle to have a larger distance from fret to string than the end of the neck. The locations for this would depend upon where your are measuring the relief at. It is also possible that a high or low fret at you measuring location could result in what you are seeing.  
 
Keith

[rustyg61]

Keith, I put a straight edge on my neck & I have .08 relief at the 10th fret & .12 relief at frets 5,6, & 7. This is measured with a feeler gauge, not the same scale as the StewMac gauge. There is little to no relief above the 12th fret. Do you think I need more relief overall? I know it's harder to get low action on a short scale than a long scale, but I was hoping some short scale owners would respond & tell me what their measurements are so I can see if mine is right or if I can make it more uniform in the upper register.
 
Thanks for your input!

[oddmetersam]

OKay, I'll shamelessly put my dunce cap on and raise my hand for clarification. Hopefully, I'm not the only one confused by all this, but even if I am, I'm willing to reveal my own ignorance since I've just changed to a light gauge of d'addarios and my bass is buzzing like crazy. Somehow, I think this dovetails with this discussion. But if not, sorry!
 
1) If I'm holding my bass in playing position, backbow means the MIDDLE of the neck is bulging towards or away from me?
 
2) Obviously, forward bow is the opposite, but which way (clockwise vs. counter-clockwise) should you gently and subtly turn the truss rods to decrease or increase the respective neck conditions? I'm sure most of you already know all this, but if you actually read most people's instructions, they are not explicit enough.
 
The movie Philadelphia was on TV last night and Denzel Washington kept saying, pretend I'm a 9-year old (or 4 or 2) when asking for clients to start at the very beginning of their stories. If that's good enough for DW it's good enough for me. LOL!
 
Thanks.

[oddmetersam]

OKay, I'll shamelessly put my dunce cap on and raise my hand for clarification. Hopefully, I'm not the only one confused by all this, but even if I am, I'm willing to reveal my own ignorance since I've just changed to a light gauge of d'addarios and my bass is buzzing like crazy. Somehow, I think this dovetails with this discussion. But if not, sorry!
 
1) If I'm holding my bass in playing position, backbow means the MIDDLE of the neck is bulging towards or away from me?
 
2) Obviously, forward bow is the opposite, but which way (clockwise vs. counter-clockwise) should you gently and subtly turn the truss rods to decrease or increase the respective neck conditions? I'm sure most of you already know all this, but if you actually read most people's instructions, they are not explicit enough.
 
The movie Philadelphia was on TV last night and Denzel Washington kept saying, pretend I'm a 9-year old (or 4 or 2) when asking for clients to start at the very beginning of their stories. If that's good enough for DW it's good enough for me. LOL!
 
Thanks.

[rustyg61]

Sam, I'm no expert, which is why I'm soliciting help here too, but I can tell you that back bow means your neck is bending backwards towards you as you hold it in playing position, & forward bow means your neck is bending away from you.  If you just went to lighter gauge strings they will have less tension on them than your old strings so most likely that allowed your neck to bow backwards which will result in your strings being lower & that is why you have buzz. Try loosening your truss nuts 1/4 turn & retune & see if that helps. You may have to go more than 1/4 turn, but I've found with my SCSD it's best to do 1/4 turn increments & let it set overnight & see where it settles. When you loosen the truss nuts the neck bows away from you making the action higher & when you tighten the truss nuts the neck bows towards you making the action lower. Generally you need a little bit of forward bow, also known as relief to keep the strings from buzzing.

[bigredbass]

Sheesh, I should never look at numbers after midnight after work . . . .
 
OK, NOW I get it.
 
Just lower the bridge to where you think it feels like your five-string.  (I'm guessing somewhere around a 16th to an 8th of an inch) If you get a little buzz in the middle, crank in a bit more tension on the truss rods.  There is some point close by where you're going to get all you're going to get out of it with your style and strings you're using.  Of course, the reverse is true:  Do this and if it begins to buzz at both ends, you may need to add a bit of relief (lossen the rods) to fix.
 
I just went to new strings (Nickel Xl's, 50-135, I like bigger G's and D's) and touched up the action on the Elan.  With the B string, I'm sitting on about 2mm (I don't know the conversion to decimal English fractions)clearance over the 24th fret, and it would not play right until it was almost dead straight.
 
Essentially, with the adjustable nut and bridge, I'm running about the same clearance over the first fret (nut slot height) as I am clearance over the 24th fret, and using the relief to fine-tune the action height (this is the way Anthony Jackson has his Foderas set up), and I basically shoot for dead-straight then let enough relief back in to kill the buzzes.  And of course its' higher on the bass side than the treble by just a little.
 
With reasonable guages, the method is the same for any scale.
 
Why am I back on here at 10 till midnight again?  Somebody better proof-read me once more . . . . . but these guys already have proof readers:
 
http://www.garywillis.com/pages/bass/bassmanual/setupmanual.html
 
. . . . and the long-form gift from Jerzy Drozd:
 
http://www.jerzydrozdbasses.com/akcndfr54jdhrei567/Ultimate_Guide_ver100.pdf
 
I'm going to bed now . . . .
 
J o e y

[cozmik_cowboy]

....back bow means your neck is bending backwards towards you as you hold it in playing position, & forward bow means your neck is bending away from you.
 
That would be the headstock, Sam.  In backbow, the middle of the neck bulges toward the strings, in forward bow, toward you.  
Tightening the truss rod will bring the head toward you and the middle toward the strings   Loosening - adding relief - will, of course, move the head away from you & the middle toward you.  
 Your righty-tighty is looking from the end with the adjustment nut.  
Holding your Alembic in playing position, turn the nuts down - toward the G on a standard-tuned 4-string - to tighten, and up - toward the E - to loosen.
On a Gibbie-style headstock-accessable truss rod, this would be accomplished in the opposite fashion; up to tighten & down to loosen.
Hope that makes sense.
 
Peter

[keith_h]

Rusty,
Sounds like you are asking more about relief profiles. Specific measurements will be hard to use due to differences in relief settings and some variance in the hand made necks.  
 
Both of my short scale basses have the classic taper. I use a Fender heavy pick for setting relief at the 7th fret. Not sure what the thickness is but it seems to be a good starting point for me the tweak from.  
 
On my Brown Bass I set the distance to 1mm (~3/64) between the 24th fret and E string. A little less on the G side. I took some measurements in the 10th-14th fret range and found all of them to be greater than the 24th fret measurement(all were less than 1/2mm difference). They all had a decrease in difference as you move away from the center point.  
 
On my Series 1, which I have never been able to get down as low as the BB, I set to 1.25mm-1.5mm (~1/16-5/64) at the 24th fret. Same results on measurements compared to 24th fret.  
 
I did notice a difference in the neck profiles as far as the relief goes. On my BB the most relief seems to be around the 11th-12th fret where as on the Series 1 it appears to be around the 10th-11th fret. This might explain the setup differences I have. I'm just doing rough measurements so the center point could move a bit if I took more time and used a more accurate measure.  
 
I did some setup comparisons to member Alan's short scale once and found them to be similar to what I have on the BB. His short scale is a comfort taper.  
 
I've sent you an e-mail.  
 
Keith