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Bass Intonation/Compensation Help!
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Author:  j.Brown [ Thu Aug 24, 2006 5:15 pm ]
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I am making a 34.5" scale Flattop Bass. Anyone know how much compensation I need? I can only assume it will be slightly more than my 6 string acoustic, right?
Its going to be a 5-string, BTW.
Thanks.

-j.
Author:  j.Brown [ Fri Aug 25, 2006 3:50 am ]
Post subject: 
Anyone?
Author:  Dave-SKG [ Fri Aug 25, 2006 3:59 am ]
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I'll try...Most of the basses I work on are electric although I did recently put a new bridge on a standup ( i know... different animal). Anyway, most of my intonation work has been retro-ing BFTS on them. I notice that the intonation set ups are much more than regular guitars. What I mean is that if I am expecting to see a change of an 1/8th of an inch on a given string on a six string I may see a 1/4" or more on a bass. I know this doesn't help much except that if you use a S.M. saddle locator in conjunction with their Saddle intonator you can probably get what you want...only you will have to slot the bridge after you have attached it to the top. They make an excellent jig for that too. I always slot my bridges after attaching them to the top.

p.s. you could make it fretless...then it wouldn't matter ...I know not funny....
Author:  David Collins [ Fri Aug 25, 2006 4:43 am ]
Post subject: 
5 string 34 1/2" scale - that could be whole lot of tension for a flat top.
What Kind of strings do you plan on using? Dean Markley, DR, Rotosound
and Thomastik all make 5 string phosphor bronze sets, and the
intonation line is going to be very different for each of them. Whether or
not the any lower strings are tapered at the saddle will give you a very
very large difference as well. You may also want to check where the taper
begins for the tuner as well. I think that a 34 1/2" scale will put the taper
or at least the silk wraps coming past the nut on most string sets.

For non-tapered bass strings I would say an average of .100"-.
175" (treble-bass) compensation, or perhaps .125"-.225" range on an
acoustic. If the lower strings are tapered you will probably need a split
saddle to move them forward enough.

I guess the best way to be sure is to get a set of the strings you plan on
using set them up on a 5-string electric where you can adjust the
intonation. Set it up a little higher than electric to approximate the action
on your acoustic, set the intonation and measure how much
compensation you needed. You'll probably be using a 34" scale electric,
but the 1/2" difference won't have any sizable effect in the amount of
compensation. And of course, saving the final bridge slotting for last is
always a good idea.
Author:  j.Brown [ Fri Aug 25, 2006 6:05 am ]
Post subject: 
Dave & David - thanks for the info. The S.M. won't work for my scale length, so I may have to make my own. I'll see how my friend's F Bass is set up. It may be a 34.5 already. Thanks again.
-j.
Author:  TonyKarol [ Sat Aug 26, 2006 1:49 pm ]
Post subject: 
Tell me the gauges and frequencies they are tuned to, and I can run my fretcalc program and give you the readouts for comp. I use it for multis and baris, and it works great.
Author:  A Peebels [ Sat Aug 26, 2006 2:19 pm ]
Post subject: 
I just measured my Taylor AB-1
G string 34"
E string 34 1/4"
Sorry no B string
For an acoustic with no mag pickup You may like Thomasick acousticores. I use them on the Taylor. Once they settle down (takes about a week) they have a really nice acoustic sound.

Al
Author:  A Peebels [ Sat Aug 26, 2006 2:25 pm ]
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Measured my Fender Jazz 5 string
G string 34"
B string 34 3/8"

All I had handy to measure was a yardstick, but these will get you close.

Al
Author:  j.Brown [ Sun Aug 27, 2006 3:02 pm ]
Post subject: 
Tony,
The set I plan on using is a 5 string phosphor bronze going .045 - .105
Any chance I can get that calc?
Thanks!
-j.
Author:  j.Brown [ Sun Aug 27, 2006 3:03 pm ]
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Thanks, Al!
Author:  TonyKarol [ Sun Aug 27, 2006 11:43 pm ]
Post subject: 
Hi J.

I had to fudge some numbers in the calc, because I dont know what things like the weight per inch or actual core gauge of the strings, but it looks like some where from .100 to about .473 are the numbers. I would use a 1/4 inch saddle, 3/16 min, and centre it on these numbers, then you have all the leeway you should need to dial it in. Go to the local shop and measure some some acoutic basses in there for an idea as well if you can. The more you know ...
Author:  Scooter B [ Wed Aug 30, 2006 12:41 pm ]
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Al,

Thanks for the bridge info on the AB-1 Something I won't have to bug you about later
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