Double Bass String Theory: Choking the bass?!

Dutch Williams

Dutch Williams

Apr 14, 2021
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#1
Do higher tension strings CHOKE the top of the bass allowing it to “speak” less? I read somewhere lower tension strings (like guts) let the top “speak” or “breathe” more (?). I’m honestly not concerned with it from a functional standpoint just more interesting to toss around conceptually/theoretically. Let the educated heads speak!
 
#2
It depends on the DB. Some DBs love high tension, some love low tension.

I have a pet theory that if your sound post is tighter between the top and back, you're better with lower tension strings, and if your sound post is looser between the top and back, you're better off with higher tension strings. But that's just a theory and it's really hard to prove unless you have an adjustable length sound post, a variety of strings to test with, a lot of DBs to test on, and a lot of time on your hands.
 
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#3
I always thought it's vice versa. The string vibrates, this makes the bridge to vibrate, the vibrating bridge then makes the top desk to vibrate, the sound post makes the bottom desk to vibrate in phase (the same way) as the front desk. It seems logical that the stronger the string is, the more powerfully the string vibrates, the more powerfully would the front desk vibrate, because it's getting stronger impulses.

However, the vibration of the front desk is by no means simple thing. Also, the vibration of string differs quite a lot type to type. It's easily imaginable that if these two things are not well alligned, seemingly unlogical things might happen.

For illustration on the string differences: I measured round and flat string on the same bass guitar once:
precision-Flats-vs-Rounds.png
X is frequency, Y is loudness. You can see that the rounds (=orange) vibrate much more strongly in higher frequencies. But in the lows and mids, the bigger flexibility of rounds makes the string vibrate not only on the desired harmonics (=peaks), but also in between (the orange narrows are much less steep than the blue ones). The flats (=blue) have much less highs, but also much less 'rumble' between peaks. The sound of flats is weaker, but it plays only 'what it should play', resulting in (perhaps) clearer pitch and timbre perception. You have to decide yourself what is better: strong vibration all through the spectrum, or clear vibration only where it should - this is on everybody's taste.

This is of course not double bass related. But you can see that the strenght and flexibility of string affects the sound in a complex way. I believe the difference between guts and steels would be similar (guts would be closer to flats as the thicker string would be less flexible). I would measure it too, but I would need a university grant to pay for strings and luthier to do the right setup. Perhaps the breathing quality of guts, as you describe it, might come from the clearer definition of tone.
 
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#4
Dutch Williams said:
Do higher tension strings CHOKE the top of the bass allowing it to “speak” less? I read somewhere lower tension strings (like guts) let the top “speak” or “breathe” more (?)
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Double bass is a complex system and as soon as we want to make an accurate calculation, we will find ourselves in difficult conditions. But this does not mean that there is no theory. The strings and bass are a single oscillatory system and cannot be considered separately. For every bass, there are the most suitable strings, but keep in mind that there is no general idea of the sound. The sound that is received on optimal strings may be liked by some, but not by others. It's a matter of taste.
Low tension strings push the natural resonance frequencies of the bass downward and increase the amplitude of the vibration. We can say that the bass will "breathe" more freely, but you need to understand that this does not mean a better sound. If the top is tight and heavy, then this means impedance mismatch, masking of overtones, etc. For a light and thin top, weak strings are good, and heavy strings will "squeeze" the bass, since they will pull it harder, shift natural frequencies up and decrease amplitude ( in theory). All this changes the timbre, attenuation, volume and other characteristics and allows you to "find" the desired sound. Bad in theory can be good in perception.
 
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#6
It has to do with clamping the top.
The shape of the top is already a clamping (pressure) in one direction: out. The top can vibrate more freely when the outward and inward pressure is similar (and not too large).

Since these pressures depend on the construction of the bass, there is no easy answer how much pressure on the top is needed to get an optimal sound.

Beyond the string tension also the string angle at the bridge influences the pressure on the top. This can be varied by the angle and overstand of the neck and the position of a (raised) saddle.
 
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#7
dhergert said:
It depends on the DB. Some DBs love high tension, some love low tension.

I have a pet theory that if your sound post is tighter between the top and back, you're better with lower tension strings, and if your sound post is looser between the top and back, you're better off with higher tension strings. But that's just a theory and it's really hard to prove unless you have an adjustable length sound post, a variety of strings to test with, a lot of DBs to test on, and a lot of time on your hands.
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I agree.

Also, I feel a tight sound post can choke the sound even with strings that match the bass well. My ‘60s carved bass, which I’ve gigged for decades, often has told me this. Winters the sound post can be tight and this bass can sound less punchy. The bass has medium Spiros.

I recall a winter gig where we played unamplified. It was a jazz trio with trumpet and acoustic guitar. The first hour was in a warm large room. My bass had the symptoms of a tight sound post. No depth, punch or growl and I could not hear my notes well. It sounded like a lower quality laminate bass. I could of used my smaller amp.

The second set, a while later, was in the same building but on the concert hall stage. By then the bass had warmed and loosened up. It’s sound was very different. Warm and punchy and I could hear my notes. I did not need an amp.
 
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#8
I'll play devil's advocate and muddy the waters further: Some players like high tension strings. I'm one of them. If a string bottoms out when you really hit it, it's automatically not for me. If a string takes too much time to speak on the front end, it's not for me.

But this stuff is all subjective. I have three friends who are well known high level pros, all of whom like lighter setups than I do. All three sound amazing with those setups. None of them like to play my main bass, but all are complimentary about the sound and feel I get with that setup. One of them was fond of saying things like "how you get that sound out of that barbed wire, I will never understand...but keep doing what you're doing!"

My take is that one person's "choked" is another person's "punchy", and that one person's "hollow and unfocused" is another person's "resonant". I'm sure that there are some physical limits to what a top can take on one end and a minimum amount of energy needed to get the top moving on the other, but in my experience most decent basses have a lot of room in between those two extremes and the rest is dealer's choice/player's preference. As always, I could be wrong, and EEMWSOCB.
 
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#9
Don't listen to @Chris Fitzgerald, he drinks in the morning. Sure, there are preferences and I think that people who prefer Spirocore Starks, for example, have built up to that over time. New DB players coming from BG usually prefer lower tension strings. How you play with your right hand is a major factor in how you want your strings to respond.

But, there are basses that need more tension to speak. There are other basses whose tops will not vibrate beyond a certain point. I have a bass that I think physically would fail under a certain amount of tension. If I were shopping for a new bass, this is one of the main things I would be evaluating. I'd be looking for on that sounded and felt like I wanted it to under Spirocore Mittels. I've played basses like that, for mine to sound and feel the same, I have to go down in tension.

Set up can and does make a difference, up to a point. For normal, healthy basses, with enough setup, probably anything is possible. For older basses with tons of "character" often you have to work with what the bass wants and can handle.

But read a ton of our lengthy threads on specific strings and see how differently they are one bass to the next. Sometimes even literally the same string. e.g. - I try some strings, opine on them, maybe make a recording and then mail them to you and you're opinion of that string is totally different. Someone also recently commented on something that up until that point I was the only one who I had ever heard claim this - that the character of a D string changed based on which G string was installed next to it. The cumulative and neighboring tension effects not only the string, but other strings as well.

As has been said, they are really complex instruments, especially older ones. Find what works and try to stick with it.
 
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#10
TroyK said:
Don't listen to @Chris Fitzgerald, he drinks in the morning. Sure, there are preferences and I think that people who prefer Spirocore Starks, for example, have built up to that over time. New DB players coming from BG usually prefer lower tension strings. How you play with your right hand is a major factor in how you want your strings to respond.

But, there are basses that need more tension to speak. There are other basses whose tops will not vibrate beyond a certain point. I have a bass that I think physically would fail under a certain amount of tension. If I were shopping for a new bass, this is one of the main things I would be evaluating. I'd be looking for on that sounded and felt like I wanted it to under Spirocore Mittels. I've played basses like that, for mine to sound and feel the same, I have to go down in tension.

Set up can and does make a difference, up to a point. For normal, healthy basses, with enough setup, probably anything is possible. For older basses with tons of "character" often you have to work with what the bass wants and can handle.

But read a ton of our lengthy threads on specific strings and see how differently they are one bass to the next. Sometimes even literally the same string. e.g. - I try some strings, opine on them, maybe make a recording and then mail them to you and you're opinion of that string is totally different. Someone also recently commented on something that up until that point I was the only one who I had ever heard claim this - that the character of a D string changed based on which G string was installed next to it. The cumulative and neighboring tension effects not only the string, but other strings as well.

As has been said, they are really complex instruments, especially older ones. Find what works and try to stick with it.
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totally feel this ... its the finding thats so beautiful .... im romanticizing sticking with one set up of strings ... im a super aggro pizz player (Mingus). that to me is the beauty of the instrument. spiro mittel E and A, pirazzi slap D and G for now .... UNTIL NEXT WEEK MWAHAHAHAH :cool:
 
#17
Don Kasper said:
Hey! Are those from "Gilligan's Island?"
Skipperrrrrrr!!!!
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Well worn Sperry Topsiders that have never seen socks. And, yes, I do wear these to the gig. (You don't suppose that's why I don't get more call-backs, do you?)
 
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