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Double Bass The Traeger Bass Book Is Here

#41
Doug Ring said:
Sorry to hijack a little, but that clear simple explanation of A0/B0 matching has me worried for a friend now!

He has realised that the neck on his Kay is too thin and gives him right hand pains, especially now he has arthritis. He was going to get a luthier to add strips to the back of the neck to flesh it out a little. But from what you've said, Ken, that could upset the A0/B0 balance and therefore the sound of the bass, right?
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Yea right, but it could also improve the resonance by matching resonances that were mismatched to begin with.

The concern of injury makes AO/BO matching a distant concern. Keep this whole concept in proper prospective... this (matching) is a refinement technique that may change playability and sound only to a certain degree, although Traeger does at times indicate a sort of go-no-go, stating things like "the bass went dead" and phrases such as this. For example, when Glen More accidentially knocks the head off his lion bass, the bass sounds much much better, Trageger states that Moore just leaves it off for a while since the bass is better that way. This is an indication that the BO resonance is better matched with AO when the neck is lightened.
 
#46
arnoldschnitzer said:
What does "better" mean?
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Arnold, maybe you didn't understand my post. Maybe I did not put quotes in where they belonged. Traeger writes in the book that Glen Moore likes the sound of HIS bass better with the lion head off. Traeger does not go into specifics as to what better means.

Do you have an opinion on AO/BO or other resonance matching as a shop technique?
 
#47
I'm going out on a limb and what I'm going to say is probably an oversimplification of what is involved.
That said, "matching" means matching a value that is measurable. In this case it is a resonance frequency, or a harmonic of that fequency, analogous in some ways to tuning two instruments to a matching pitch. Since the mass of the neck, fingerboad, and machines together determines the value of the BO resonance, it is possible for the total mass to be too much or too little for the BO value to match the AO value. You can read "match" as AO=BO for practical purposes and generally there is no easy way to adjust the AO in a finished double bass, so the BO is adjusted by adding or subtracting mass to/from the neck, fingerboard and machine area.

In some cases improvements can be made by adding mass, in others by subtracting as long as the result is matching resonance frequencies. The closer they are to a perfect match, the better the neck, fingerboard, etc. vibrates constructively (in harmony) with the body. The idea is that one part of the instrument is not damping the vibration of the other part. I suppose you could get too much of a good thing and have a very sing-songy instrument, but that is where taste comes in. A better "match" is one closer to "equal".

I hope that is a fairly accurate synopsis of the goals of resonance matching. It makes perfect sense for it to be a desirable quality in an instrument. And it should almost act like a supercharger on an engine, or an electronic feedback loop. Some of the vibration absorbed by the neck will be reflected back to the string if the the neck and body are tuned. If not the engergy will be diffused and perhaps even return as a distructive wave.
 
#48
Ken McKay said:
Do you have an opinion on AO/BO or other resonance matching as a shop technique?
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All I know is that of all the great bass makers I am personally aware of, none employs this technique. IMHO, it is a case of trying to quantify the un-quantifiable. Making a fine bass is a mixture of craft, intuition, logic and magic.
To elaborate on my quip above, "what does better mean"; One person smiles when the tension is low, while another frowns. One bassist digs a tone where the bottom is pronounced and everything else rolls off, while another wants to hear the overtones. One calls a fat bottom "luscious", while another hears it as "muddy". Every player has his/her own idea of what sound they want to emanate from their instrument. That's why I always ask, before trying to adjust a bass tonally, "What would you like to change about the tone or response?". Mr. Traeger's famous opening remark is, "I guarantee your bass will sound better when you leave than it does now". What is "better"?
 
#49
What does better mean wasn't the question here, Arnold. The question was what is AO-BO matching. I think you are changing the subject from the objective to the subjective.

AO-BO matching is objective, measurable, and observable. That is objective quantitative scientific reality. Whether the instrument sounds "better" after any change, measurable scientifically or not, is a matter of taste and that is subjective. We can discuss subjective qualities all day long and accomplish nothing of note in instrument design. If we study quantifiable effects, we can add them to our tool kit in designing and making instruments more to our liking, or not. AO-BO matching is a certain definable thing. What it sounds like to you, me, or anyone else is an undefinable thing. :rolleyes:

As far as anything being due in part to magic, well, let me say that magic is what we called misunderstood natural cause and effect phenomena before we had science that could establish a mechanism for the link between cause and effect. Science is still largely an "explained" magic in a sense.

We do understand vibration physics quite well by now, though. Bridges (not the ones on basses, but the ones that cars cross rivers on) are designed so that the mass is distributed in a way so as not to set up resonances with common wind speeds. It is a way to keep the bridge from collapsing during sustained winds. The same physics applies to anything that vibrates for any reason.

I suspect that some luthiers incorporate AO-BO matching in construction without knowing it. Particularly if someone discovered the mass relationship and incorporated it into the designs of the early master instruments. Since most modern instruments are copied carefully in materials and proportion, we should come up with similar, albeit inexact, AO/BO ratios. Keep in mind that the early masters didn't need to know why it worked, just that it did. During that age, anything discovered like that was due to "God's perfect design" or perhaps magic. Now we develop scientific models to explain and measure the same phenomena. The fact that the resonance is close to matching on many instruments indicates that some luthiers knew about it and used it. It is just better understood after another 300 years of polishing our measuring tools.
 
#53
PROTRACTED POSTERER said:
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I suspect that some luthiers incorporate AO-BO matching in construction without knowing it........................ ................ ................... ........................... .............. ........................... ......
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It's possible. I'm pretty sure Arnold's BO is unintentional. Jeff? Ya think?


Then again, I'm not the only one around here who plays one of Arnold's basses and loves it. If he says he built them without a thought given to AO-BO matching, then that's good enough for me. :)
 
#54
[/QUOTE] That's why I always ask, before trying to adjust a bass tonally, "What would you like to change about the tone or response?". Mr. Traeger's famous opening remark is, "I guarantee your bass will sound better when you leave than it does now". What is "better"?[/QUOTE]

Got it Arnold, you should write a book too, I'll be one of the first to buy it!!!! :D

Seriously, the bass community needs direction, and real dialogue here. I know it gets boring for the experts like You, and Nicoli and Jeff Bollbach. And you certainly can't pass on the knowedge here in the forum. So... disagree with the book, but if you have any extra time, do give a little explanation and maybe a tidbit from your shop.

I must add also that any time I have asked a direct question I have gotten a good direct answer from all of the "experts" here.
 
#56
If people were cooking food before it was discovered that cooking made food safe by killing micro-organisms, then it is plausible that instrument makers performed the final whittling of the scroll / neck / fingerboard until a resonance matching was achieved (particularly if the result is audible or noticeable in the way an instrument plays) before resonance was understood in any scientific way. No one had to understand the physics of the process to employ the mechanics then and (perhaps unfortunately) no-one need understand why it works for it to work now. People have been cooking food since the stone age whereas the germ theory of disease is barely 150 years old. It is quite common for the use of technology to exceed the explanation of technology by many years.

Actually it is good that there is some controversy and dialogue about this process because that is ultimately how an understanding of it will be reached. It may contribute only slightly to creating better instruments, but any tidbit gained is a victory for all the makers down the road.

And I, like others, would buy books in addition to Traeger's, in hopes to increase my skill and knowledge about these instruments. In Traeger's defense, if he knows anything about AO-BO, it was responsible for him to include a discussion of it in his book regardless of whether the phenomenon is generally accepted as valid or not by others. His book would be incomplete without it.

If Arnold S. or Nick L. wrote a book, I wouldn't expect them to write about aspects that they think are trivial and I would buy it and read it to find out what they do think is important. Perhaps their book(s) would be complete without a discussion of A0/BO.

There will always be new understanding of old phenomenon, and losing knowledge is easier than gaining knowledge. Sometimes (like in the case of Gregor Mendel), a whole lifetime of scientific endeavor remains obscure until years after the researcher's death. In America, the patents and "rocket science" of John Goddard were filed away for more than 15 years before Germany built the V rocket bombs. Americans were wondering where the Germans got the idea and the patents were on file in Washington D.C., ignored (except by the German scientists).

Perhaps somewhere in the recesses of some European Library there is an obscure Latin paper that discusses the effect (who knows what it would have been called then) of AO/BO resonance matching. Perhaps not. But we do know what it is now as well as how to measure and describe it and I'm glad Traeger was not too timid to include a discussion of it of it in his book, however poorly understood or rarely implemented the process is in practice.
 
#57
That said, if your friend wants to fatten the neck of his Kay, I'd suggest he have a luthier add a wedge shaped shim between the neck and the fingerboard.
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This is good advice, Eric, thanks. I'll pass that on to my friend. It sounds a lot more workable than building up a profile on the back of the neck and changing the whole feel of a bass he's played for 50 years.

The concern of injury makes AO/BO matching a distant concern
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And that's a fair point too, Ken. He does play amped most of the time, so that would enable any changes to the sound to be compensated for.
 
#58
Chris Fitzgerald said:
It's possible. I'm pretty sure Arnold's BO is unintentional. Jeff? Ya think?
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My BO is AOK.

Silversorcerer, calm down! No one is maligning science. I'm alive because of it. Ken asked who is doing AO/BO and I responded that I don't know anyone. That said, if someone came into my shop with the equipment, did a demo and convinced me it offered a significant benefit, I'd consider doing it myself. You have built zero basses. Is it really polite to lecture me about advances in science and luthiery? I have an opinion to which I am entitled. This does not mean I want us to go back to living in the dark ages. And yes, I do believe "magic" is involved. Isn't music magic; how it can evoke an emotional response without physically touching a person?
 

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