Scale Length and String Gauge: How They interconnect?

rumbler · #1 02-16-2008, 01:40 PM

Hey all just wondering.

If I was using a 130 B on a 35 inch scale bass, what gauge would I need to use to get the same tension on a 34 inch scale bass? What type of math of physics calculation is involved in this?

Anyone know the answer to this?

Andrew

knuckle_head · #2 02-16-2008, 03:04 PM

T = (UW x (2 x L x F)²) / 386.4
UW = (T x 386.4) / (2 x L x F)²

T: tension in pounds per linear inch
UW: pounds per linear inch
L: scale length in inches
F: frequency in hertz

A direct answer would be; .135 (within 1/2 pound or so of tension)

rumbler · #3 02-16-2008, 03:12 PM

So what your saying is that I would need a 135 on a 34 inch scale bass to get the same feel of a 130 on a 35 inch scale?

Wow. So would it work as a general rule of thumb to just add .05 to all my strings if I was to use that gauge on a 34 inch scale? or should I calculate each individually? I really suck at math and that equation you just made confuses the hell out of me

(i failed grade 11 and 12 math in high school)

Andrew

knuckle_head · #4 02-16-2008, 03:38 PM

It isn't that simple sadly. The kicker in the formula is that it works off of mass, and a percentage of it at that.

If you consider the relationship between the two scale lengths and the two gauges you have about the same percentage on there relationships; roughly 103.4%

If you multiply the gauges you have now or are happy with on your 35" scale length by 1.034 you ought to be close. I'll warn you that when the gauges get smaller it will give you increments other than .005, and with skinnier strings you are better to go a bit thinner than thicker when you have to fudge it.

DavePlaysBass · #5 02-16-2008, 04:10 PM

When going from 34 to 35, the tension increase is ~6%. Likewise going 35 to 34 is ~6% decrease.

At 34" scale, a DA XL 80 is about 42 lbs. A 6% increase would be around 44.5lb. An DA XL at 34" is about 48.4lbs. This difference is about 15%.

So in this example, the scale length change of 1" has less effect than the string gauge change of 0.05". If you wanted things to be exactly the same, the string would need to be somewhere in between.

So if you step up a gauge (assume 0.05" increase), on a 34", it will be a little tighter that the 35" with the lower gauge. If you leave it the same, it will be a little looser on the 34" (obviously). Unless you think you have too little tension at 35", I would stick with the same gauge on the 34". I think the feel of a large gauge is more than just the tension. Its the actual diameter that feels larger.

rumbler · #6 04-01-2008, 09:00 PM

Wow, I am going to attempt to resurrect this thread!!

I know anthony Jackson uses a 125 on a 36 inch scale! so what would that be on a 34 inch scale to get the same tension? a 140?

Math confuses me so sorry if this is annoying/retarded

cnltb · #7 04-02-2008, 02:01 PM

Quote:

Originally Posted by rumbler

Wow, I am going to attempt to resurrect this thread!!

I know anthony Jackson uses a 125 on a 36 inch scale! so what would that be on a 34 inch scale to get the same tension? a 140?

Math confuses me so sorry if this is annoying/retarded

Is AJ. using 125?
I heard it's 120...

Bass Below · #8 04-02-2008, 02:29 PM

A .125 on a 36" scale is roughly 35 lbs. To accomplish that on a 34" scale, a .135 puts you at roughly 36 lbs.

A .140 would probably give you around 38 lbs. which would be better IMO, but ideally a .145 is my minimum for a B on a 34 incher.

rumbler · #9 04-02-2008, 06:27 PM

Maybe that is why AJ's B string sounds like a sonic meltdown when he plucks it!

jayp883 · #10 04-03-2008, 06:05 PM

Quote:

Originally Posted by knuckle_head

T = (UW x (2 x L x F)²) / 386.4
UW = (T x 386.4) / (2 x L x F)²

T: tension in pounds per linear inch
UW: pounds per linear inch
L: scale length in inches
F: frequency in hertz

A direct answer would be; .135 (within 1/2 pound or so of tension)

dadgum................

spade2you · #11 04-03-2008, 07:09 PM

Quote:

Originally Posted by Bass Below

A .125 on a 36" scale is roughly 35 lbs. To accomplish that on a 34" scale, a .135 puts you at roughly 36 lbs.

A .140 would probably give you around 38 lbs. which would be better IMO, but ideally a .145 is my minimum for a B on a 34 incher.

While the tension may be the same, the end result isn't always the same. Dingwall and Knuckleworks probably wouldn't be using their extended scales if you could simply use a really thick low B. The problem with using thicker strings is that you often lose articulation higher up on the fingerboard, especially if you need to raise the action to avoid floppy sounds.

My Conklin uses a taper core .127 stainless steel string and is 35" scale. I haven't really experimented with low A tunings on it, but the B is everything I could ask for. It sounds thick and articulate while being very useful thoughout the fingerboard. Some 34" scales I've played with a .135 tend to start having overtones near the 9th fret or so, depending on the bass.

Bass Below · #12 04-03-2008, 10:09 PM

Quote:

Originally Posted by spade2you

While the tension may be the same, the end result isn't always the same. Dingwall and Knuckleworks probably wouldn't be using their extended scales if you could simply use a really thick low B. The problem with using thicker strings is that you often lose articulation higher up on the fingerboard, especially if you need to raise the action to avoid floppy sounds.

I know, that's why I bought a Knuckle

spade2you · #13 04-03-2008, 10:19 PM

Quote:

Originally Posted by Bass Below

I know, that's why I bought a Knuckle

I really wish I could try one of those out. I'm a tad hesitant since a 35" scale 6 kinda dwarfs me. I'm takin' enough of a chance ordering a narrow 7 string 37-33".

Bass Below · #14 04-03-2008, 10:29 PM

Quote:

Originally Posted by spade2you

I really wish I could try one of those out. I'm a tad hesitant since a 35" scale 6 kinda dwarfs me. I'm takin' enough of a chance ordering a narrow 7 string 37-33".

If you can hook up with someone near you that has one, definitely try it out. I don't have mine yet, but Skip was awesome enough to lend me his personal Quake for a while and it is truly phenomenal. I'm a short guy with sausage fingers and playing the 39.5" scale was effortless. I adjusted to it before I finished the first song I tried on it. The articulation of notes well below standard B was mind blowing.

spade2you · #15 04-03-2008, 10:44 PM

Quote:

Originally Posted by Bass Below

If you can hook up with someone near you that has one, definitely try it out. I don't have mine yet, but Skip was awesome enough to lend me his personal Quake for a while and it is truly phenomenal. I'm a short guy with sausage fingers and playing the 39.5" scale was effortless. I adjusted to it before I finished the first song I tried on it. The articulation of notes well below standard B was mind blowing.

If I do alright with the fanned 7, I might look at maybe a Quake 5 or so.

As for trying stuff out, I'm lucky enough to try out Mike Z's Curbows. Nebraska is the land o' non-custom basses. People look at my rig and scream witchcraft.

Bass Below · #16 04-03-2008, 10:49 PM

Quote:

Originally Posted by spade2you

If I do alright with the fanned 7, I might look at maybe a Quake 5 or so.

As for trying stuff out, I'm lucky enough to try out Mike Z's Curbows. Nebraska is the land o' non-custom basses. People look at my rig and scream witchcraft.

LOL, well if your travels ever bring to the New York City area, let me know, you can try mine out.