• TalkBass has been independent since 1998. Add your voice.
    Create a free account to reply to discussions, view embedded media, and browse with fewer display ads.
    Join free Log in
    Want zero display ads or expanded classifieds tools? Compare plans.

Double Bass How much does scale length effect tone?

Will_White

Will_White

Jul 1, 2011
4,171
5,797
Salem, OR
#1
Since the DB side of Talkbass doesn't have a Luthier's corner and I don't think I'd get the responses I need from the other side I thought I would start a thread over here. I am designing an upright style bass for playing arco acoustically. I have a 34" scale upright style bass I built for the BG luthiers corner 100$ bass challenge and I have it set up to get good pizz volume, I still need to tweak a couple things but its coming along. It has a couple things that I can't change, namely scale, body width, that make it dificult to play arco so I'm going to build another with a tighter fingerboard radius, and an arched body. It's going to have a body that's slightly taller then a standard double bass and not as wide so it has a similar volume to a 3/4 upright. What I'm not sure about is if it would work well with a scale length between a 1/2 and 1/4 upright of 37-38"
 
#3
The answer to the question in your thread title is that scale length affects tone a lot. Beyond that I'm not sure of the question. Will a shorter scale still make a bass sound? Yes. Will a 36" bass sound as rich as a 41" bass? No. Will a tall thin body sound the same as a classically proportioned one? No, but you might like it all the same.
 
  • Like
Reactions: Tom Lane
#4
Steven Ayres said:
The answer to the question in your thread title is that scale length affects tone a lot. Beyond that I'm not sure of the question. Will a shorter scale still make a bass sound? Yes. Will a 36" bass sound as rich as a 41" bass? No. Will a tall thin body sound the same as a classically proportioned one? No, but you might like it all the same.
Click to expand...
While I trust that it's what you meant, I think it's worthwhile to add "all other things being equal" to your responses. For example, "Will a 36" bass sound as rich as a 41" bass?" All other things being equal, no. Under that assumption, I agree with what you said. Of course, there are basses with a shorter scale that sound richer than ones with a longer scale. As we know, all other things are rarely equal. Sometimes the variance across basses swamps that produced by a change in one factor. That often makes it difficult to generalize.
 
  • Like
Reactions: Tom Lane
#5
Scale length is only one factor in creating string tension. Neck angle is another. Overstand is another. Tailpiece geometry is another. String tension -- duh! -- is another.

String tension is only one factor in creating a sound. There's string material, body material, fingerboard planing, body shape and other factors. Each matters a lot.
 
  • Like
Reactions: Tom Lane
#6
longfinger said:
In the thread just below this one ".. 4th/5th tuning .." , Post #4 you can see and hear a video of a double bass with 38" string length using new special strings (tuned in 5ths). Check it out and follow the links.
Click to expand...

You might notice that the low C string is on the weak side compared to the others. Could be the string length, could be the string, could be...
 
#8
Will_White said:
So if you were to make a list of things that helped acoustic volume and projection what would it be?
Click to expand...
An amplifier and a good cabinet!:D The output is very much acoustic. Okay, okay, seriously... here's my list:

1) Technique! Pulling out a big sound is very much about the hands and the arms.

All other things being equal, and in no particular order:
2) Moderate to high string height
3) Good choice of string for the particular bass
4) Larger body-- vibrating string length will go along with this
5) Carefully performed setup

None of these will matter much without a good design from the start.
 
  • Like
Reactions: Sam Sherry, Tom Lane and DC Bass
#11
Tom Lane said:
Thinking about this a bit... I notice that my Eminence lacks the "depth" that my upright has. Words fail me here, so maybe you guys can help me out explaining the difference in tone? Amplified, with the treble and mids turned down and the bass boosted, depending on the amp, I think it sounds pretty similar to an an amplified upright with a pickup but the tone seems to be missing the aforementioned "depth". I have the original foil Realist on mine. None of my BLs have complained but it's less satisfying to me, less "rich", "complex"? Is that all overtones? The string length is within 1/2 inch of my upright and I've had the same strings on both at times so it's mostly the narrow body? Acoustically, I've heard the Eminence derisively called a "bass dulcimer" which... is a pretty cutting, but maybe accurate, comment because without amplification, it's pretty quiet and, again, words fail me, but "nasal"? And, last my NS Omni with a FBG string-length and solid body sounds different yet then a FBG with a similar scale length.

On the flip side, bass guitars have a much shorter string length and whether fretted or fretless, I can usually tell the difference in tone between them and an upright with a pickup. And the Kala Uke-basses have a remarkable tone for such a short scale product with a tiny acoustic sound box, so the weird strings make a big difference?

I suppose, I'm supporting the previous responses that string length is just one factor of many, but, on the other hand, it does seem that physics are largely limiting the possibilities.
Click to expand...

I think you've identified a fundamental problem-- pun fully intended!

Unless I'm missing something, string length and body size are, in practice, confounded variables. For example, one essentially never encounters a large body size with a short mensure. Body size and, thus, cavity volume and shape directly determine resonance frequencies. All other things being equal (AOTBE), a larger body will better support propagation of low frequencies. That's physics. Now, does it matter what string length is producing those frequencies when attached to the body? I think to the extent it does, it's largely related to the fact that, on a larger body, the string must be longer so that it reaches the bridge placed at its optimal position. Back to the confound-- you simply don't put a short string on a long body and have it vibrate at the appropriate place. I suppose the experiment to do would be to install a false nut, swap on a shorter string, tune appropriately and test that arrangement. Hmm... what shorter string? Now one has to trade tension against mass-per unit length (or, even better, see here) to arrive at the desired frequency.

The spectral profile of a plucked DB string is such that the second harmonic (first overtone) has the greatest energy. So, take the E string. The fundamental is at 41 Hz and the greatest energy lies at 82 Hz. Now, what I don't know and what seems not so easy to determine (at least for me) is how the spectral profile changes with different trades among tension, mass-per-unit-length, and scale length. Different combinations of those can all yield a string tuned to 41 Hz. For different combinations, what will be the relative energy in the first and second harmonic? I don't know.

The differences you report are, indeed, related to the overtone structure but my saying that doesn't help much because that's basically, by definition. What I've tried to point out is that the final overtone structure is related to a number of factors (e.g., frequencies supported by the body and all of the string factors that are traded to yield a desired fundamental frequency). I think this helps to explain the variety of results you cited across different forms of basses. In other words, it ain't so simple. Maybe someone else can jump in here and clarify things. :)
 
  • Like
Reactions: davpal, Tom Lane and james condino

Latest posts

Top Bottom
Back