Bass VI Strings on an Acoustic Guitar

[Oscar Stern]

I've wanted to put a set of Fender 24-100 Gauge Strings (24, 34, 44, 65, 80, 100) on my Jasmine S-35 Acoustic Guitar so I could make it into an Acoustic Bass VI that has lots of volume on a small body. What I did was to crush down the ends of the strings to have them fit into the tuners.

 

[HaphAsSard]

I've wanted to put a set of Fender 24-100 Gauge Strings (24, 34, 44, 65, 80, 100) on my Jasmine S-35 Acoustic Guitar so I could make it into an Acoustic Bass VI that has lots of volume on a small body. What I did was to crush down the ends of the strings to have them fit into the tuners.

Cool! How's intonation at the 12th fret? Do you feel it could use a compensated saddle (something like assembling a makeshift one, made of six retracted b-string segments from common acoustic-guidar bridge saddles), or an overall bridge repositioning? or is it close enough?

 

[Oscar Stern]

Cool! How's intonation at the 12th fret? Do you feel it could use a compensated saddle (something like assembling a makeshift one, made of six retracted b-string segments from common acoustic-guidar bridge saddles), or an overall bridge repositioning? or is it close enough?

It intonates very well,

 

[Deleted member 271037]

It intonates very well,

Even if it intonates well (which I have to admit I find rather doubtful, because it should at least be 100% impossible if you're using the stock, compensated saddle) I would be extremely worried about the string tension. An acoustic guitar isn't made for the tension you get with Bass VI strings tuned to (presumably) E-standard on a 25"(ish) instrument!

If it works, by all means enjoy it. But don't be surprised if the bracing/top/bridge/neck/neck joint of your guitar can't handle the tension over time. It might not be a slow gradual process either, but something rather more dramatic where strings and pieces of wood will shoot through the air...

But then again, I haven't actually calculated the tension. Maybe it will work better than I think. I guess the shorter scale might lower the tension enough with those strings. Do the strings play nicely? I would have expected them to be a bit floppy with that scale?

 

[HaphAsSard]

But don't be surprised if the bracing/top/bridge/neck/neck joint of your guitar can't handle the tension over time. It might not be a slow gradual process either, but something rather more dramatic where strings and pieces of wood will shoot through the air...

Nah.

But then again, I haven't actually calculated the tension. Maybe it will work better than I think. I guess the shorter scale might lower the tension enough with those strings.

Yah.

You don't even have to guess too hard.
For an instrument to be tuned an octave down while having the same tension as it currently has, gauges need to be doubled. This holds true, for plain steel strings, with any pair of notes an octave apart and any pair of gauges, one double the other. You can verify it with any string tension calculator. Wound strings, of course, complicate the picture, because there's no way of knowing if two strings, let's say a .042" and a .084", have the same exact internal construction, only scaled-up. However, playing with the aforementioned calculator shows that the truth is never too far from the aforesaid rule of thumb.
Let's take, by way of example, a very common acoustic-guitar string set, not even a heavy one. Let's say
12p-16p-24w-32-42-53.
Sure, there are lighter ones out there, but also heavier, as said (13-56, and even 14-59). A decently-made dreadnought should take a 12-53 in stride, non?
Well, in order for a player to have that dreadnought tuned from E1 to e3, a suitably-gauged set in the same ballpark tensionwise would be as follows:
24p*- 32p** - 48 - 64 - 84 - 106.
* (which exists, and is roughly equivalent to a 26w)
** (which doesn't, but if it did its tension would be about that of a wound 035)

Now, gauges for the Fender Super 250B6 set are
24w - 34 - 44 - 65 - 80 - 100.
Even assuming bronze-wound strings to have the same tension as nickel-plated steel strings of same gauge (the former are slightly more massive), the only string from the Bass VI set with the potential to be tighter than the corresponding scaled-up guitar set would be the 065 D, and only by a RCH, if at all.
_ _ _

Next, let's see harder, or lightly-extrapolated data if you will.
The D'Addario EJ16 (acoustic guitar, phosphor bronze, gauges 12-53 as detailed above) has the following tensions in pounds:
23.36, 23.31, 30.06, 29.93, 28.93, 24.95, for a total of 160.54 lbs.
The top half of the Fender VI set has gauges identical to the D'Addario EXL156, so one should expect tensions not to be spectacularly different from the latter's, i.e. 27.48, 30.1 and 30.62 lbs at 30" scale ->
19.85, 21.75, 22.12 lbs at 25.5" scale.***
We're already several pounds behind, as in: lower than an acoustic guitar is commonly subjected to.
Finally, in order to have a reasonable guess of tensions from the 65-80-100 subset of the Fender Super 250B6, let's look at the D'Addario EXL170S (nickel-plated steel, short-scale bass). Tensions at 30" scale for those three strings are 37.72, 31.25 and 27.09 lbs, respectively, which become
27.18, 22.58, 19.58 lbs at 25.5" scale.***
*** [to get tension values at a scale other than a given one, multiply each value at the old scale by the ratio of scale lengths, squared, with the desired scale at the numerator. in this case, (25.5/30)^2 = .85^2 = .7225]

To sum it up -
- tensions of a bog-standard acoustic guitar set installed on a normal-scale acoustic guitar:
23.36, 23.31, 30.06, 29.93, 28.93, 24.95 (total 160.54) lbs
- probable tensions of a bass-VI set, in its intended bass-VI tuning but on the same acoustic guitar:
19.85, 21.75, 22.12, 27.18, 22.58, 19.58 (total 133.06) lbs.

QED.

Nor should the result be a surprise. Let's repeat the mantra: fat strings are only heavy-tension, compared to thin ones, if you tune them to the same pitches. If you do not, all bets are off: it all depends on the exact pitches and scale.

 

[Oscar Stern]

Even if it intonates well (which I have to admit I find rather doubtful, because it should at least be 100% impossible if you're using the stock, compensated saddle) I would be extremely worried about the string tension. An acoustic guitar isn't made for the tension you get with Bass VI strings tuned to (presumably) E-standard on a 25"(ish) instrument!

If it works, by all means enjoy it. But don't be surprised if the bracing/top/bridge/neck/neck joint of your guitar can't handle the tension over time. It might not be a slow gradual process either, but something rather more dramatic where strings and pieces of wood will shoot through the air...

But then again, I haven't actually calculated the tension. Maybe it will work better than I think. I guess the shorter scale might lower the tension enough with those strings. Do the strings play nicely? I would have expected them to be a bit floppy with that scale?

They're an Octave lower than regular Strings so the tension is fairly low.

 

[Deleted member 271037]

They're an Octave lower than regular Strings so the tension is fairly low.

Excellent!. Based on HaphAsSards numbers your guitar should be fine.

They're not too floppy either? It's often a VERY fine line when doing stuff like this...

 

[Oscar Stern]

Excellent!. Based on HaphAsSards numbers your guitar should be fine.

They're not too floppy either? It's often a VERY fine line when doing stuff like this...

No problemo, my Guitar will be OK.