Double Bass 5 to 4 string ?

[Bob Branstetter]

My question was an honest inquiry about AO/BO matching's affect on wolf reduction. Many luthiers (myself included) continue the search for the "holy grail" of wolf elimination, and I posed a simple question to you, an avowed believer. Frankly, if you said it was a cure, I would likely try it out. My question did not warrant your harsh and unfriendly response.

I'm sorry if you felt my response was inappropriate. If my memory serves me correctly, you asked the very same exact question when this was under discussion a couple of years back. I remember well where that discussion went and as I have said previously, I have no intention of rehashing all of that. If you want to find a cure for wolfs, it will not be found in A0-B0 matching. However, you just might find what you are looking for in How to IMPROVE the RESONANCE CONDITIONS of Musical Instruments by VIBRATION-DEDAMPING, Elimination of Wolf Notes, Other Adjustments by Prof. Gerhard A. v. Reumont, Translated from the German by Lothar Tews. (And before anyone asks, I will not rehash that one either.)

I don't want to give the impression of being "harsh and unfriendly", I simply do not have any desire to enter into a discussion of something which has already been discussed to death in a previous encounter. Yes, I am an avowed believer in A0-B0 (for Ken - that's "A Zero - B Zero" ) and will gladly answer any questions addressed to me in either PM or email, but it is not something that I wish to debate again on TB as long as there are people who are willing to condemn it without any first hand experience. I am not accusing Arnold of anything. I have the greatest respect for Arnold Schnitzer as both a person and a luthier, but I made a personal decision when I decided to return to TalkBass that there would be some things that I will not discuss on any terms other than my own. That is the way it is going to be. If you don't like it, that is not my problem.

 

[Silversorcerer]

More like a brake job, new tires, and a wash and wax

This could be done with great results without even taking the top of.....trust me.....yes one may think the bar is larger and the arching thicker but it would add the ridgidity to the top that those instruments usually lack....thus resulting in possibly a better sounding bass. And chances are the top and bar are standard as they give with a 4 just with a retro neck.

Eric what is the width of the bridge from outside foot to outside foot in mm?

Obviously you and I drive different vehicles and play different 5-string instruments as well. The thicker and deeper bass bar in my (5-string) extends to within a half inch of the neck block and within an inch of the end block, but I guess the Eastmans are different? And the width of the upper bout on mine is greater than that of the 4-string model from the same maker, but again the Eastmans might be different. And then there is that extra length at the pegbox, which shouldn't cause any problems other than looking like a vacant lot in a row of brownstones. The neck on mine is not significantly thicker than a 4 string, but it is a good bit wider.

I think your car analogy is more like a new strings, new soundpost and general clean-up than it is a true conversion and seems to indicate that there are no significant structural differences between a 4 and 5 string instrument, or that the 5 string Eastman is not properly constructed and should have been a 4 string instrument to start with. If the internal structural and dimensional differences that I noted don't matter, then why are these present? Please explain.

 

[uptonbass]

Its really not as big deal as you may think, the other direction yes but even on your bass, trust me it would pass well. Have you done one?

 

[Silversorcerer]

Actually, no Gary, I haven't and I probably wouldn't in any case. Why wouldn't I? Because even though as you said:

This could be done with great results without even taking the top of.....trust me.....yes one may think the bar is larger and the arching thicker but it would add the ridgidity to the top that those instruments usually lack....thus resulting in possibly a better sounding bass.

It could also possibly not result in a better sounding bass. It could result in one that has too stiff a top and less resonance than a properly built 4-string instrument. That is unless, as your statement implies, the 4 string Eastmans lack adequate rigidity ("usually" of course, but you don't say always). And secondly because even though:

chances are the top and bar are standard as they give with a 4 just with a retro neck.

The nature of the top and bar are historical facts and chance (or perhaps risk is a better word) is a property only of the future. The top and bar are either stiffer than on a 4 string or not, and we don't know at this point with certainty.

Let's review what we know. The bass was made as a 5-string. Because that is a historical fact there are no possibilties about it's construction because that is already done, there are only unknowns which could only be resolved by inspection and taking careful measurements. Your best guesses are stated in the language of uncertainty;- "possibly a better sounding bass" and "chances are, ...." Maybe conversion is a good idea and maybe it's not. Since there is considerable labor in slimming down the neck and this is not reversible, wouldn't it be safer and less risky just to sell the 5-string to someone who wants that and get a 4-string instead???

 

[Paul Warburton]

PM sent.....

 

[uptonbass]

Silver, sorry man but I am just not going to get into this with you any further. I can't write or gab as well as you but I may remind you what I do all day long....every day. I wont go on about my reputation or experience or ask you what your experience is founded on.

Stop trying to read between the lines in what I have written.

 

[drurb]

Silver, sorry man but I am just not going to get into this with you any further. I can't write or gab as well as you but I may remind you what I do all day long....every day. I wont go on about my reputation or experience or ask you what your experience is founded on.

Stop trying to read between the lines in what I have written.

Actually, all Silver needs to do is read carefully. You stated clearly across two posts that for both the Eastman and for Silver's 5-er which apparently has a thicker, deeper bar and wider bout, that, in your opinion, the conversion you suggest would work quite well.

Yes, you said, for the Eastman, it could "possibly" result in a better sounding bass. It is clear that your opinion is that it could be better and, perhaps, the same but not worse.

Yes, you said that "chances are" that the top and bar are standard. You also made it clear that if they are not (as in Silver's 5-er) that it would still work fine.

So here's what we know. Your opinion, as a luthier, is that whether or not the construction of the bass in question was modified for being a 5-er, the conversion would be just fine. There seems to be little uncertainty in your posts with regard to your opinion.

Now, it is just a matter of whether folks here would trust your judgment as a professional luthier or Silver's.

I know where I'd place my bet.

 

[Silversorcerer]

I think what is more important is whether those reading would trust the structural integrity of pegbox cheeks that rest outside the width of a thinned down neck.

 

[drurb]

This thread is getting weird at the least.

Agreed-- too much noise.

 

[Silversorcerer]

You think this could be a problem?

This thread is getting weird at the least.

If the pegbox mortice width is greater than the width of the neck at the nut, this a structural compromise waiting to fail. This critical juncture between the neck and pegbox cheeks is much more solid, resistant to spitting and strain, if the mortice width is somewhat narrower than the neck width such that the neck directly supports a portion of the width of the pegbox cheeks. On DB's built as 5 strings, both the the pegbox mortice and the neck are wider than on DB's built as 4 strings. If one simply narrows the 5 string DB's neck to 4 string width, the cheeks of the pegbox will rest on wood that is unsupported by the neck width, and this compromises the structure of the pegbox right at the point where it bears the most force. It is an engineering physical fact, not just an opinion or a thought.

 

[drurb]

If one simply narrows the 5 string DB's neck to 4 string width, the cheeks of the pegbox will rest on wood that is unsupported by the neck width, and this compromises the structure of the pegbox right at the point where it bears the most force. It is an engineering physical fact, not just an opinion or a thought.

You speak of "engineering physical fact." I think Ken has addressed the specifics adequately and detailed how problems can be avoided. Let us assume, however, that the neck is, in fact, thinned under the pegbox. Just because the force is now distributed over a smaller area (a physical fact) does not mean that it will fail or even come close to doing so. That is an extrapolation made without justification. Surely, it is not the case that any thinning no matter how small will cause failure. The issue then, is how much will produce a problem. Ken offered, "A mm or two will not hurt any structure unless there are other problems already."

In order to answer the question analytically, one must know exactly what are the various forces. In reality, the question will not be answered analytically at all. In practice, we rely upon the expertise and experience of luthiers who are familiar with the construction and stresses of the instrument. From all indications, those experts are saying, "No problem."

 

[Paul Warburton]

What about basses like my five Bohmann...he maintained a decent sized neck by laying the FB over the B side to accommodate the extra B string?

 

[Silversorcerer]

Ken, the extent of the compromise will depend on how close to the bone or over one goes with the reduction of the neck width, and this obviously will vary according to the specific bass, but in any case the same piece of wood is weaker when it is thinner.

On most of the basses I've seen, there is some portion (sometimes only a few mm.) of the pegbox cheek width that is directly above and supported by the width of the neck. This is a structurally important relationship. If those few mm are removed, either from the insides of the cheeks or the outsides of the neck, then instead of the neck width acting as structural support for the cheeks it becomes a fulcrum with all of the stress force of the string tension acting on the bottom corners of the pegbox. There are two structural compromises at work. The first is the thinning of the neck and the second is the introduction of a levering force if enough wood is removed such that the pegbox cheeks are entirely outside of the neck width. The second compromise is the worst of the two. The failure may not be immediate, but the assembly will withstand less of a bump on the scroll without breaking than it would before the alteration, and over time the levering force on the wood will weaken that area of the neck and pegbox even if it doesn't get bumped because the wood there is constantly under a stress that it otherwise would not bear.

In the specific case of my 5-string (neck width at nut below cheeks = 2 5/32" pegbox mortise width = 1 31/32" so we have 3/16" or about 5 mm of safety overlap total) if the neck were reduced by 2.5mm on each side, which is still not enough to really make it a normal width for a 4-string, that would be too much and the cheeks would be bearing down with leverage.

Picture the pegbox cheeks resting upon the outside edges of a solid block, then picture them resting on both ends of a see-saw. The see-saw plank is bearing levering forces, but the block is just bearing direct force. Obviously the plank will give way before the block.

I will make an educated guess about this type of conversion: I'm guessing that given the rarity of 5-string basses in the USA that were built as 5-string basses that there are few even very experienced luthiers who have done this type of conversion more than a few times. I'm also guessing that the 4 to 5 conversion, even though seemingly more complex, is also more common. And this pegbox/neck relationship is not a consideration when going in that direction unless one widens the pegbox mortise. I'll also guess that most of the 5 to 4 conversions where the neck is thinned to the extent of introducing the levering force hold up pretty well for a while, but eventually will result in cheeks that shear off of the neck even with the sides of the neck or even with the insides of the cheeks.

 

[Silversorcerer]

What about basses like my five Bohmann...he maintained a decent sized neck by laying the FB over the B side to accommodate the extra B string?

Paul, I think that your Bohmann was conceived and built exactly as it is today and has happily suffered no second guessing!

I have seen one reproduction of a historical stringed instument (medieval and definitely not a double bass;- I'll see if I can locate a photo) that has a similar fingerboard and neck relationship as your Bohmann.

It's the relationship of the pegbox cheeks and neck that I'm addressing above, and your Bohmann is unique in that it has ebony running all the way up into the top of the scroll and that reinforces everything in that whole path so it is clearly an exceptional case in terms of what bears most of the stress in the scroll and pegbox. You ever think about changing it to a 4 stringer, you just let me know.

 

[Paul Warburton]

Paul, I think that your Bohmann was conceived and built exactly as it is today and has happily suffered no second guessing!

I have seen one reproduction of a historical stringed instument (medieval and definitely not a double bass;- I'll see if I can locate a photo) that has a similar fingerboard and neck relationship as your Bohmann.

It's the relationship of the pegbox cheeks and neck that I'm addressing above, and your Bohmann is unique in that it has ebony running all the way up into the top of the scroll and that reinforces everything in that whole path so it is clearly an exceptional case in terms of what bears most of the stress in the scroll and pegbox. You ever think about changing it to a 4 stringer, you just let me know.

I'd love seeing the picture you mention. I'm actually in the market for another giging bass. It's just too heavy for an old fart like me. No ,i'm not entertaining any thoughts of selling the Bohmann...unless someone make me an offer I just can't refuse.I need a bass with some depth in the ribs too move some air. But it has to be lighter than the JB at 30lbs. without a case!

 

[Silversorcerer]

The offset fingerboard was a feature of a medieval stringed instrument called the cittern. The late Bernard Ellis built a reproduction of a cittern that can be seen at this link: Link Removed Since the entire URL would not copy, click on "instruments" at the left margin and then click on the photo captioned "cittern" to see an explanation of the neck and fingerboard relation, which features an overhanging FB on the bass side of the neck similar to Paul's Bohmann. Of course on the cittern it is all one piece of wood carved into this shape instead of more pieces glued, but the function and form is the same.

 

[drurb]

Silver--

I truly appreciate the thought and obvious knowledge that you have brought to bear regarding this issue. Please re-read my previous post. For now, I accept that the forces and changes you mention are quite real. The question is what their actual effects will be. In the end, if all of the forces you mention are not measured, it comes down to experience, expertise, and judgment.

More specifically,

...but in any case the same piece of wood is weaker when it is thinner.

Indeed, but is it so thin as to fail?

...The failure may not be immediate, but the assembly will withstand less of a bump on the scroll without breaking than it would before the alteration.

This may be strictly true but the question is whether it is of significance. What is undetermined in all of this qualitative talk is where on the function we are operating. Failure may still require a massively abusive bump. Short of abuse, failure may not be inevitable.

...I'll also guess that most of the 5 to 4 conversions where the neck is thinned to the extent of introducing the levering force hold up pretty well for a while, but eventually will result in cheeks that shear off of the neck even with the sides of the neck or even with the insides of the cheeks.

We arrive here at a crucial matter of judgment and this is really what it is all about. Given that one will not be approaching this via analytical, scientific approaches, it is a matter of expertise in judging whether all of factors to be taken into account will result in any sort of instability or premature failure.

Personally, I am assuming that professional luthiers like Upton and Arnold and even some highly-experienced non-luthiers like Ken are well aware of the issues you have identified. In short, their "guess" is that the conversion can be accomplished safely and effectively. One should weigh heavily the fact that the luthiers mentioned have, apparently, actually done such work.

 

[drurb]

Talk about a pissing contest, huh?

This thread has two possibilities now. It will either calm down and get back on topic OR get CLOSED.

Bets anyone, odds?

Who is the official TB 'bookie'?

Okay, okay, I know this is in good fun but, for the record, I tried very hard to be objective and non-argumentative. I can only hope I succeeeded.

In addition, the thread has hardly gone off topic. I also don't see any nastiness at all. So far, the interchange seems cordial and healthy. Sorry Ken, I have no intention of drawing blood so don't figure on taking ring-side bets.

I am only trying to point out that knowing about the factors involved and in which direction changes will lead is not sufficient to predict an outcome. Expertise rules the day for this one.

 

[Silversorcerer]

We arrive here at a crucial matter of judgment and this is really what it is all about. Given that one will not be approaching this via analytical, scientific approaches, it is a matter of expertise in judging whether all of factors to be taken into account will result in any sort of instability or premature failure.

Personally, I am assuming that professional luthiers like Upton and Arnold and even some highly-experienced non-luthiers like Ken are well aware of the issues you have identified. In short, their "guess" is that the conversion can be accomplished safely and effectively. One should weigh heavily the fact that the luthiers mentioned have, apparently, actually done such work.

-Point conceded. And very well reasoned, too.

I would urge caution to those who boldly wield the knife and encourage them to be more aware of possible structural engineering issues when altering instruments. It is quite possible to measure all of these forces (string tension is usually between 50 and 60 lbs., pulling at an angle so the levering force is a sum of torques dependent on the distance between the nut and the spindles and the angles of those paths) and compare them to the shearing limits of hard maple of a given thickness and width parallel to the grain. It would surprise me if this hasn't been done by some makers. I'm certainly not out for anyone's blood here nor am I trying to undermine experienced professionals. Perhaps I have pointed out something for some to consider, if not a deciding issue in this case, I'll accept that.

I still don't think the conversion is the best idea, considering that there are many 4 string basses available and with patience I think the bassist who began this thread could find a buyer for a good sounding carved Eastman 5-string. I hope that opinion will be respected.

 

[drurb]

Non-argumentative for you in my mind would include a 100% blood transfucion at the least. Same goes for Silver as I KNOW he's listening.

You guys get so technically wordy for a pair that has never restored a Bass between the both of you. Sit back a second and imagine what it would sound like listening to Jeff and Arnold have this same discussion back and forth INSTEAD of You and Silver.

Well, I have remained cordial and your comments on my style certainly steer this off-topic. As you can see from Silver's post, there is no animosity here, just friendly debate.

I believe you have missed the point of the discussion. Silver and I were discussing principles of approach and the manner of drawing conclusions. Those are not unique to luthierie. Silver and I respectfully disagree regarding whether there is evidence that the particular factors he mentioned are significant. I, for one, was deferring completely to the luthiers with regard to making the proper judgments. In fact, that was a large part of my message. I was touting the salience of the expertise and judgment of those who have done the restorations. I would think that would be a point with which you, of all people, would agree!

Not every disagreement must degenerate into a war of words. As you see, the back and forth between Silver and I did not. No "pissing contest," nothing personal, just discussion.