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Double Bass Traeger's Soundpost Thoughts

#61
OMG-LOL said:
Ok, lesse if I can remember... Two slices of cheese, bread in the middle, butter on the inside, no. Butter, cheese, bread, no. Bread, butter, cheese....

TARTER SAUCE!!!!! :bawl:
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***.jpg




Uh, more about Traeger, anyone? :)
 
#64
Chasarms said:
In light of this piece of knowledge, I would ask that we temporarily set aside discussions of luthiery and other relevant endeavors to address a more pressing question:

How come the "non-stick" pan that I paid $65 for won't let go of my grilled cheese?
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Off topic: Whatever oil or fat that was used was heated to the point of decomposition into carbon;- the long way of saying, "You burned it, dude." Heavier oils will burn at higher temperatures. Use a heavier oil for your grilled cheese making or a lower temperature. :)
 
#65
T-LOL said:
Where on earth did you find that? Am I the first to be so honored?
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By me, yes. :D Somebody posted that up in BG-land, and it amused me so much I swore I'd slap it on the first non-sequitur I found...which just happened to be your post. That's pic's a doozy, innit?

(Ahem) Now, more about Traeger, soundposts, and the argument between scientific precision vs. intutive craft. :eyebrow:
 
#68
Silversorcerer said:
Has anyone participating here, other than myself, tested the post position on the top and back while bowing a note to compare the strength of the vibration at the post position to that of the surrounding wood? Is anyone willing to risk independently replicating my findings?
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To what end? What were your findings?
 
#69
"With respect to vibration, a node is a point that remains still with vibration radiating around it, like the nodal points that are determined by harmonics on the string. So if you think of the top and back as 3 dimensional strings, the soundpost produces a node on them that vibrates less than the surrounding surface. It follows that the amplitude of vibration increases farther from the post, but there could be other nodes as well, but the soundpost would be the determining one, the soul. I tried placing my finger on the soundpost spot and plucking the strings and yes, I could feel that the sound post spot doesn't vibrate as much as the surrounding wood."

-Quoting myself from a previous post in this thread on page 2;- sorry;- we're on p. 4 now. Several independent replications of these results would indicate that the soundpost functions as a node (pivot point, or fulcrum), and as such the post is relatively still compared to the movements of the top and back and rather than transferring vibrational energy from one to the other, the post actually synchronizes the wave forms of the two. It could not be proven with this finding, but it could be reasoned further, that stiffer tops and backs would benefit from stiffer posts (the idea of impedance matching of posts to tops/backs). This would tend to support Traeger's contentions about the function of the post and be in agreement with the separate findings in a German scientific investigation to which he refers. It likewise would render the idea of the post as a driving pistion and frequency filter questionable. I hope I have been clear.
 
#70
Silversorcerer said:
Has anyone participating here, other than myself, tested the post position on the top and back while bowing a note to compare the strength of the vibration at the post position to that of the surrounding wood? Is anyone willing to risk independently replicating my findings?
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First of all I just want to say that Arnold is either on or on his way out of town for a while. So he's not likely to respond to any of this-not that he would anyway he just might be fed up.
Second of all, what the HELL are you talking about? I have to know- are you just conducting one big ENGINEERED troll and have I bit? Is anyone willing to risk replicating your findings? That's a very condescending thing to ask in this room. If you are asking it in the same room as a person with the type of chops Arnold has, unless you are an as to yet unknown luthier wunderkind ya might better ask if you have licked his boots clean in a proper and respectful way. I have been a professional luthier [bass only] for 20 years now and have more than a few folks other than my mother who swear by my work. I have seen plenty of work done by people with ocilloscopes and spectragraghs and whatever and I for one am not impressed. Most can't even properly fit a soundpost much less determine its optimal impedance. But I am not the only one. The guys out there who are making the violins that'll impress em in 2200 just smile when they hear this kind of talk. But they could be wrong and I guess so could I. I mean after all you put your finger on your bass and now you are in league and accord with the great Charles Traegar and the infallible Germans. That's your finger science. I find myself wanting to use my finger in a typically [mine]unscientifically way.
On the subject of the post wood. Do you really think that the Kay guys were on to something? I'm sorry, I like Kays for what they are and some of them are killer for jazz no doubt- but these are not well ENGINEERED instruments at all. For a number of reasons. If you have ever examined an original post you will see that it is a much harder wood than spruce and it has a deep slot cut into it from midway up to the top. Maybe the slot is a tone slot, designed to match the A0 of the post to the B0 of the top. Not really, it was done for speed in the setting of the post and a spruce post cut in this same way would likely split. The cheap ass wood that Kay used was near impossible to split. That's why they used it. Of course if you don't believe that you can easily fit it into your impedance theory.
 
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#71
I don't fault the SILVER SLIPPER for a little scientific jawboning. I don't really see as how anybody has made any claims yet that could amount to a theory (or an insult, for that matter, but I'm one to talk given some of my recent carryings-on.) Just a whole lot of disagreement about how to describe things and what makes sense to spend time thinking about.

Practical, day after day bass-makers and tweakers are standing on some pretty strong legs when they arch an eyebrow at some of the ways science folk carry on.

As for your soundpost thinking, SS, there's this little image showing the shape of soundwave emanation from a violin:

[Invalid or Expired Link Removed]

Can't remember where I found or saw this but you'll have to trust me: I'm not an idiot when it comes to research and this came from some science-oriented violin site.

Seems clear to me that the sound emanates from the bass bar. The soundpost acts as a column, tying everything together into a system that allows the bass bar movement to occur. I'm a total rookie, but given what I see here and how I understand things to work, I suspect that soundpost placement has a much greater impact on the performance of the system than soundpost composition or even soundpost shape. Soundpost fit is for efficient coupling but also -- probably more importantly -- for not screwing up your back or top plates.

When I put my finger on top of the soundpost, I don't feel any (or much, anyway) vibration. I don't expect there to be any.
 
#72
Responding to Damon: Nice illustration. The sound wave patterns clearly emanate from the moving bass bar side. Not exactly the same vibration pattern that I am talking about, but the illustrated pattern does not conflict with the idea of the post as a node in the top and back plates, rather it supports it because if the whole top were moving the center of the emanating waves would not be so concentrated.

Jeff B., I don't really know how to respond to you. You seem rather angry. Let me try to clarify: I was trying to make the point that the post places a node on the top and the back and that in this way it influences the vibration patterns in both the top and the back in the same way;- that previous independent investigation has shown this to be true, and there is a simple way to test it with just about any bass fitted with a soundpost. This is central to the discussion of Charles Traeger's ideas about the soundpost's function, which is the subject of this thread. Some people who have not read the book have posited their own ideas which may or may not be in conflict with Traeger's and/or my own. Ideas can be tested, as the illustration Damon has included show, as the paper Trager sites shows and as my rather simple touch the post while bowing shows. One probably doesn't need to be a luthier wunderkind to do it. And the point you are trying to make is?????

I think we are all in general agreement that I have no, or at least very little, practical luthiery experience (well, I did once carve from a spruce 1x2 and install an "emergency" soundpost for a bass that inadvertently left the shop on a Friday sans post so that it could be used without damage for a weekend gig. I searched for and found the proper dimensions for the soundpost on the web and probably had it approximately right. There were pencil marks in the bass so I didn't fuss with it too much and on Monday it went back to the shop). I have made no claims otherwise. I am not calling your credentials as a luthier or anyone's into question.

I don't really think a slotted spruce post would split (the Kay question now) unless it was improperly fitted;- as Nick pointed out, spruce is strong for its low density. Have you tested this idea? When Kay made those basses were spruce dowels relatively more expensive than hardwood? Can you back this up or is it just an extension of some disdain for factory instruments that leads to your characterization of those posts as cheap or inferior? Up until the late 80's spruce was relatively inexpensive wood. You could get it in 1x2's from the hardware store right next to the Douglas fir (which is not generally available these days either) and the pine. Can you support your contention that it was price and not design that was behind the reasoning at the Kay factory? Remember, this was in the 1960's and before. "Cheap" student classical guitars built in the USA by the hundred thousands featured solid spruce tops, solid mahogany ribs and backs as well as a low price point. I have one made by the Harmony Guitar Company of Chicago, Illinois in 1964;- great materials, modest factory workmanship. Good wood was plentiful and cheap then.

As for me setting some elaborate trap (paranoia strikes deep), my original ideas were expressed before I received the Traeger book in my entry on March 24th, at 12:36 PM. It is quite inconceiveable that I could foresee what others would post here, what I would find in Traeger's book, or how this thread would develop.

As for those who may have painted themselves into a corner, well don't try to hand me the brush now, I have my own corner to finish painting... :hiding:
 
#73
SLIVER SUPPLIER, don't go down the spruce route very far.

Straight-grained spruce splits if you look at it funny. It swells. It warps. If I am a manufacturer interested in production and making money, if I can get rid of that delicate and relatively expensive soundpost by using a hardwood dowel the likes of which can be had at Home Despot, well, why wouldn't I?

Jeff's Kay hypothesis makes total sense to me.
 
#74
If Home Depot had been around in the 60's, one might have been able to get spruce dowels there. My point was that wood in general was pretty cheap then. Perhaps slotted spruce might split. I wouldn't really know because I haven't tested it, either. The case for spruce being more expensive to use in a factory situation in those years seems weak given it's relative plentitude at the time and some factor other than cost would be more plausible, but rather than speculate further as to what that was, it just seems well enough to say that it was definitely something, and today it is not known what;- we are all guessing. The past has no possibilities, just knowns or unknowns. We do know spruce was cheap then, we don't really know why they used something else.

The spruce 1x2 piece I had was quite old, but it did come off a hardware store shelf (Ace, not H.D.) and I think I originally purchased it because it was the cheaper way to go, hardwood 1x2's being a bit pricey for my purposes then. The larger lengths were used as braces in a bookcase which I still have. That was in about 1982, I think. Anyway, it's not some huge issue. There is one fellow (Cabin dweller, I think) that uses a metal soundpost. I guess he doesn't want it to split either!! And getting the grain perpendicular must be a real challenge as well!

That being said, I am officially signing off from this thread as the law of diminishing returns seems to have set in. If anyone wants to P.M. about it, that is fine. I have done as much damage to my reputation here as "luthier wunderkind" can do in week, and am completely content with the outcome. Cheers, All, and happy Monday morning! :)
 
#75
Yeah, SS, I know what you mean.

The cheap factory spruce you're thinking of isn't the same quarter-sawn violin-grade spruce traditionally used in luthiery. I live in the land of spruce and I can assure you that, when it's cheap, it's really cheap. Soft, knotty, resinous, more warped than the Starship Enterprise.

Violin spruce is the Royalty of Spruces.
 
#76
If you wedge a support under something- your bass top, your kid's seesaw, the floor of your house, you will undoubtedly limit vibration at that point. The lever, the fulcrum, not NASA-level concepts.

Let's put Kay basses in historical perspective:
They were production line instruments, machine-built during depression, wartime and post wartime eras, for the most part. This was largely before the invention of the electric bass, so any bass player in a dixieland, swing, bluegrass, blues, jazz, dance or early rock 'n' roll band played double bass. Kay made entry level student instruments, some in small fractional sizes, and their top of the line models appear to have been aimed at the working musician, who scrambled to make a living with his instrument. Kays were robust instruments that could survive the ravages of the classroom and the road without disintegrating. Many dimensions and design features seem to have been decided upon with more consideration for ease of manufacture than sound quality. Most of them were built before the arrival of steel strings for double bass. I think it's more good fortune than good design and engineering that many sound as good as they do.

In his book, Traeger talks about replacing the hardwood soundpost in a particularly good sounding old Kay with a seasoned spruce post. He says the sound died, and came to life again after refitting the old hardwood post.
 
#78
Yes, the standard of documentation is rather low there, isn't it? I can dig out the reference but I ain't gonna -- too much work. I've had hard drive crashes, laptop changes etc since I did a bunch of research on these topics a couple of years ago and this image sits among some of what I have left.

My thoughts on how the sound-making mechanism works don't come from only the diagram. Traeger talks about bass bar movement when he discusses the issue, but he's not the first I've heard describe it that way. When I simply think of how the system is put together (plates, sound post, bridge) I don't see as how the idea of the bridge kinda "pumping" the bass bar is unreasonable. The sound post, doing it's nodal column function thing, facilitates that pumping action. The top plate would be more "flaccid" without it.

Oh my god: nodal column function? Facilitating pumping action? Flaccid without it? Have I got something else on my mind?

It's weird to be talking about "optimizing" when our common picture of how the bass mechanism really works is so... uncommon.
 

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