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Double Bass adjustable neck basses

#6
Mario Lamarre does the adjustable neck option as well, which you can read about at the bottom of the below page.

http://www.lamario.ca/bio.php?lang=english

For a player, the interesting aspect is (copied from above link):

< If you use an adjustable bridge, the tension increases when you heighten the strings and decreases when you move them closer to the fingerboard. But with the neck the opposite happens. When the strings are moved further away from the fingerboard the tension decreases and the sound becomes more open, while bringing them closer to the fingerboard increases the tension, promoting the emission of sound. >


That means one can have very high-off the finger board strings with a low tension, or close to the fingerboard strings with a high tension. Seems useful!

I don't own one, but I'd love to have a removable+adjustable neck double bass. (If $$$ was not an issue...)

Then there are these

http://www.patrickcharton.com/en_EN/index_b21.php

very adjustable! The look takes getting used to.
 
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#8
longfinger said:
Mario Lamarre does the adjustable neck option as well, which you can read about at the bottom of the below page.

http://www.lamario.ca/bio.php?lang=english

For a player, the interesting aspect is (copied from above link):

< If you use an adjustable bridge, the tension increases when you heighten the strings and decreases when you move them closer to the fingerboard. But with the neck the opposite happens. When the strings are moved further away from the fingerboard the tension decreases and the sound becomes more open, while bringing them closer to the fingerboard increases the tension, promoting the emission of sound. >


That means one can have very high-off the finger board strings with a low tension, or close to the fingerboard strings with a high tension. Seems useful!

I don't own one, but I'd love to have a removable+adjustable neck double bass. (If $$$ was not an issue...)

Then there are these

http://www.patrickcharton.com/en_EN/index_b21.php

very adjustable! The look takes getting used to.
Click to expand...

Too bad there are no pictures of Lamarre's system. I imagine it's similar to Jim Ham's. What Charton has done is totally revolutionary, however. You can adjust pretty much any tension parameter by turning a screw. The endpin design alone should get him into the Musee des Arts et Metiers. Still, I can't say I liked the sound:hmm:
 
#9
No, LaMarre's neck removal/adjustment system bears no resemblance to the adjustment mechanism in Jim Ham's basses. James' system uses a T nut interlocking with matched parts in the top block. If you look around his website he shows excellent, sharp, high-resolution pictures from a bunch of angles. Ah, here it is:
[Invalid or Expired Link Removed]
Clicking on any thumbnail image gets you the big ones.

Mario's setup uses a simpler mechanism. It's basically a nut and bolt, holding the neck against the pocket where it used to be glued. There's more to it than that, including a locating pin and other hardware to reinforce things, but it's mostly just a very slick nut and bolt which turn quite easily at pitch, allowing the action to be adjusted by tilting the neck rather than sliding it fore-aft as with the Ham model. I've worked on one bass with Mario's neck modification and seen another bass taken down after a gig - Roberto Occipinti was kind enough to demonstrate it for me. Very easy to use.

My own first bass used yet another adjustment/removal solution. It's shown a bit on my site, though my pictures aren't nearly so nice as Jim's. You can visit www.luthier.ca and click the third link down on the left hand frame, or if you prefer here's a direct link to the bass page with lots of pictures and words about the too-long process of its creation:
http://www.luthier.ca/bass1.html
My idea sprang mostly from hesitation. I do a lot of hesitating in making things out of expensive materials, where I tend to do a lot of prototyping in cheaper stuff like metal and plastic for non-instrument related activities. Basically I didn't like anything I was seeing from LaMarre (pretty as it is, the angle change thing just annoyed me), Charton, even Ham. All great makers, but the geometry didn't seem satisfying enough to commit to in my first bass, so I hesitated. Then an idea jumped up and I went ahead and made it happen. The idea was simply to swing the neck heel through a curve, radiused from the nut, such that the string angle changes not at all when adjusting the string height. This offered a 'purity' in terms of maintaining identical pressure on the belly and string tension at every height which appealed to me. Mostly because bassists try for years to get just the right soundpost position, bridge setup, everything just so... and then throw a lot of that care out the window when they crank up the adjusters or change the tilt of the neck.

It took a fair bit of fussing over details, but using lignum vitae blocks in the neck heel and mortise pocket for a low-friction interface resolved adjustment stickiness, and a nicely machined nut and bolt (a friend of mine is an excellent machinist - I'd have made this stuff myself but I don't have a quarter-million dollar lathe) make substantial changes in string height a matter of a turn or two of an allen key. Something one can do between songs, without retuning, thanks to the geometry of the movement.

It's something I'll be evolving through the next few basses as I try to make it even easier to use - though it's pretty easy already, taking just a few minutes to knock the bass down or set it up again, with no special skills needed. It's not something I think could easily be retro-fitted to an existing bass, as the upper block is substantially different in shape, but perhaps it could be applied if someone wanted to budget enough money and time for the operation. I've a standing request for this from a symphony member who travels a few times each year for festivals, but I'm still putting him off on that. It's a really amazing old French bass and I'd rather try it on something less sacred first. It'd involve cutting into the belly a bit for the deeper heel pocket... something which goes against my rather conservative nature when it comes to fine antiques.

Anyway, I do hope other luthiers will consider trying my design and elaborating on it. Eventually we might come up with the 'ultimate' adjustable and removable neck, something many bassists would appreciate considering the often nightmarish nonsense airlines put you guys through. I've had to repair the damage airline baggage handlers do quite a few times and it's just sad. A smaller, tougher trunk with the neck separate is a huge help in avoiding such crimes. And having the bass actually work better after the operation is a bonus.
 
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#13
Ah, thought not. It seems structurally risky, making the neck length somehow slide... unless one introduced rather heavy hydraulics or something else equally sturdy. Perhaps a somewhat extended pegbox with a platform between the hollow and the fingerboard, and a removable nut with a replacement extended section of fingerboard and nut? Might work. It'd be ugly I think, but might work for switching scale/thumb stop position without getting too crazy mechanically. Another option might involved a screw adjuster under the fingerboard overhang, with the semi-cylindrical neck sliding through a matching cut-out in the neck heel on a couple of rails to maintain a snug fit. There'd have to be a bit of a bump where the heel tapered out to zero at the neck to avoid getting splinters, but only a little bump I think. Such an arrangement would be cumbersome to operate and require string tension to be taken off (and likely soundpost falling over) but it would make a bass convertible between D and Eb without a luthier getting expensively involved. Perhaps useful for school program basses?
 
#14
I am currently working on a bass project that will include an adjustable neck. I have yet to build it but my concept is very simple - T-nuts in the neck heel and two bolts adjusted through the inside of the bass via a "porthole" in the C Bout. The neck will slide in/out. A removable, adjustable neck makes a lot of sense for repair etc. Gerard's system is quite simple and aesthetically pleasing.
 
#15
Hm I guess Eb <---> D on the neck via turning some knobs is actually very complicated.

Perhaps a simpler solution would be just to allow 'swappable necks', take one off and put on another. Options on necks could be 4 string or 5 string, Eb or D, and different string lengths. Kind of like custom order basses now, but changeable after the fact by a player, because of the easy to use removable neck system.
 
#16
longfinger said:
Hm I guess Eb <---> D on the neck via turning some knobs is actually very complicated.
Click to expand...
Perhaps, but some designer will probably eventually come up with an elegant solution, if there's enough interest amongst bassists.

longfinger said:
Perhaps a simpler solution would be just to allow 'swappable necks', take one off and put on another. Options on necks could be 4 string or 5 string, Eb or D, and different string lengths. Kind of like custom order basses now, but changeable after the fact by a player, because of the easy to use removable neck system.
Click to expand...
Jean Auray has offered this for several years at least, with Renaud Garcia-Fons' bass using a 5-string neck most of the time but a 4-string neck being optional. Once the neck is removable a lot of optional necks become possible, such as a neck with an integral C-extension for orchestral playing.
 
#17
powerbass said:
I am currently working on a bass project that will include an adjustable neck. I have yet to build it but my concept is very simple - T-nuts in the neck heel and two bolts adjusted through the inside of the bass via a "porthole" in the C Bout. The neck will slide in/out. A removable, adjustable neck makes a lot of sense for repair etc. Gerard's system is quite simple and aesthetically pleasing.
Click to expand...

Hmmmmmmmm.......and where did you get this idea???????

The number one thing that really determines why something will be built is who is willing to write the check for it and what is their priority. Double basses and their neck joints are subject to huge amounts of stress and movement. Adjustability is great, but when I'm not monkeying around with it, I want things to be rock solid.

Speaking from the perspective of someone who has built several hundred instruments with removable neck designs (double bass, guitar, and mandolin) the more simple you keep things, the better it will hold up and work over the long haul. For may last double bass, I chose a system that I had a lot of experience with in other instruments, very similar to Bob Taylor's guitar neck system. It has been used on almost a half million guitars and adopted to many other instruments very successfully. I used a variation of this at the Breedlove custom shop, so I scaled it up for a double bass.

I've also had direct experience working on somewhere between 50 and 100 different styles of detachable neck systems from other builders. They all have merit and function, but they all were built with specific design parameters. A trapdoor somewhere is incredibly useful to me for a number of things. I don't like hardware showing in the heel- it always reminds me of some cheap drywall screw repairs that I run across all of the time; threaded inserts hide quite well inside the heel and are very strong when installed properly. Hardware and styles change depending upon availability and desired outcome. To be honest, I've had very fancy stuff made at machine shops that worked well and also been able to make very nice working systems out of readily available parts from most decent hardware stores. 'Depends upon the day and the job.

Removable necks rock!!!! As both a builder and a player, I regularly adopt to different customers needs, but for my personal instrument, I can't imagine ever not having that as an option after putting it to the test in the trenches for a little under four years now. The next bass I start after the holidays will have a version 2.0 of a similar, yet evolving removable neck system. I also do several removable neck system retrofits each year. I'd encourage everyone to experiment with the idea, but have some clear goals in mind. Feel free to give a call or stop by for a visit and we can chat up a few ideas and talk about some very proven designs and some designs that clearly do not work so well and how to work around them.

J.
Www.condino.com
 
#19
I am rebuilding a bass for myself, a DIY project. I am not adhering to restoration, nor is there a financial incentive involved. I'm more interested in trying out some construction ideas that appeal to me. The porthole I first saw on your bass James and I have researched other builder's work like James Ham. I have extensive experience building complex/custom furniture so I look at UB bass construction from that perspective. IMHO the traditional UB construction (large pieces of wood (neck/top and back) moving counter to neck/tail and rib blocks) is prone to failure. In furniture making you avoid "trapping" wood movement at all costs. Then there is the issue of short grain on the neck heel which is also prone to breaking since it is under string tension/stress. And lastly if a sound posts needs to be adjusted/replaced so frequently why adhere to a design that makes is so difficult? A hole in the bass makes a lot of sense.
In my current project the neck will be made of two pieces, the heel is a separate piece of wood morticed into the long neck piece w/scroll. Two pieces of wood removes the short grain issue as well as reducing the size of the whole neck blank - a proper mortice is much stronger than short grain - some could argue that stronger may not be better here at the heel. Since the heel is bolted to the body via t-nuts the neck mortice (another vulnerable joint) is removed and the movement of solid wood ribs is not constrained by these contrary wood movement issues. The second piece of wood will run the same length as the fingerboard - since it is morticed into the heel this is easy to do and it will still stand clear of the bass top. I want to try this full length neck/fingerboard idea for a couple of reasons. One is that the UB fingerboard above D/Eb is unsupported which may result in a weaker transfer of sound/energy to the body - certainly the tone of the bass changes in this register. The other issue I would like to address is that w/pizz the plucking thumb rests on the side of the FB as an anchor. I find playing on the A & E strings is more difficult/less comfortable because the thumb/index finger are too close together w/the thumb pressing on the sharp edge of the FB. I want more wood for my thumb, like a ramp, this would provide better leverage and more comfort. The other ideas are to remove all cross grain wood in the neck, tail and rib blocks. The neck is held on w/metal to metal fasteners. The neck profile is flat where the thumb rests and the scroll will be simple w/out ornament. I will also leave more wood where the scroll transitions into the fingerboard - there is vulnerable cross grain there as well. How all this turns out remains to be seen, progress has been slow


james condino said:
Hmmmmmmmm.......and where did you get this idea???????

The number one thing that really determines why something will be built is who is willing to write the check for it and what is their priority. Double basses and their neck joints are subject to huge amounts of stress and movement. Adjustability is great, but when I'm not monkeying around with it, I want things to be rock solid.

Speaking from the perspective of someone who has built several hundred instruments with removable neck designs (double bass, guitar, and mandolin) the more simple you keep things, the better it will hold up and work over the long haul. For may last double bass, I chose a system that I had a lot of experience with in other instruments, very similar to Bob Taylor's guitar neck system. It has been used on almost a half million guitars and adopted to many other instruments very successfully. I used a variation of this at the Breedlove custom shop, so I scaled it up for a double bass.

I've also had direct experience working on somewhere between 50 and 100 different styles of detachable neck systems from other builders. They all have merit and function, but they all were built with specific design parameters. A trapdoor somewhere is incredibly useful to me for a number of things. I don't like hardware showing in the heel- it always reminds me of some cheap drywall screw repairs that I run across all of the time; threaded inserts hide quite well inside the heel and are very strong when installed properly. Hardware and styles change depending upon availability and desired outcome. To be honest, I've had very fancy stuff made at machine shops that worked well and also been able to make very nice working systems out of readily available parts from most decent hardware stores. 'Depends upon the day and the job.

Removable necks rock!!!! As both a builder and a player, I regularly adopt to different customers needs, but for my personal instrument, I can't imagine ever not having that as an option after putting it to the test in the trenches for a little under four years now. The next bass I start after the holidays will have a version 2.0 of a similar, yet evolving removable neck system. I also do several removable neck system retrofits each year. I'd encourage everyone to experiment with the idea, but have some clear goals in mind. Feel free to give a call or stop by for a visit and we can chat up a few ideas and talk about some very proven designs and some designs that clearly do not work so well and how to work around them.

J.
Www.condino.com
Click to expand...
 
#20
powerbass said:
IMHO the traditional UB construction (large pieces of wood (neck/top and back) moving counter to neck/tail and rib blocks) is prone to failure. In furniture making you avoid "trapping" wood movement at all costs.
Click to expand...
There are small tricks to help avoid some of the seasonal problems associated with 'trapping,' such as leaving a saw-width relief on either side of the ebony saddle on the lower belly to avoid the very common winter cracks one sees there. Another option is to do away with the saddle altogether as I've done on my bass, an idea happily lifted from Charton's B21 bass, though I used a lignum vitae peg with a single cable position since I don't tilt the neck as he does, preserving string angle symmetry across the bridge, eliminating the need to compensate for angle changes by raising or lowering the endwire mount position. The obvious stress risers created by gluing ribs to perpendicular grained blocks at ends and corners is something luthiers have nonetheless used for many centuries. Attempts to circumvent this have had mixed results, usually involving transfer of stresses from one area of contradiction to another, with cracking again. The lesser evil is having cracks in the less important ribs, with linen swatches hide-glued to the ribs helping to spread stresses and minimize spreading of such cracks. Use of an endblock with grain parrellel to the ribs obviously endangers the belly and back rather severely.

The removable neck, however it's implemented, obviously avoids the contrary grain orientation issue at the neck heel/upper block. There's really no need to go further in strengthening the heel, provided the mounting for the neck is high enough up the heel that the endgrain doesn't split off under tension. The mechanisms used for fixing the neck to the body are more likely to fail in a fall or whatever impact than the wood if the design is good, but frankly accidents happen, and no amount of bullet-proofing is likely to avoid breakage if one is awkward in handling the bass. There comes a point of diminishing returns, where over-building defeats sound generation. Keeping it light is quite important for a loud, clear sound.

powerbass said:
Then there is the issue of short grain on the neck heel which is also prone to breaking since it is under string tension/stress. [... ] a proper mortice is much stronger than short grain - some could argue that stronger may not be better here at the heel.
Click to expand...

As above... And more joints are not better, generally speaking, in instrument construction. Unless you're building for the very short term, the differential movements of even very closely matching pieces around a joint tend to cause ugly and weak joint edge disruptions in the varnish, stuff you can feel under the hand when playing, or even leading to failures. The fewer pieces the better when making almost any instrument. I've seen a lot of laminated bass necks, and very few remain intact at the lamination joints after 30 or 40 years. A proper one-piece bass neck can last well over a century, sometimes several centuries if the bassists have been careful not to fall down stairs or let others handle their instruments.

powerbass said:
The other issue I would like to address is that w/pizz the plucking thumb rests on the side of the FB as an anchor. I find playing on the A & E strings is more difficult/less comfortable because the thumb/index finger are too close together w/the thumb pressing on the sharp edge of the FB. I want more wood for my thumb, like a ramp, this would provide better leverage and more comfort.
Click to expand...

Yeah, but just scraping and polishing the thumb edge rounded and rubbing it with a bit of mineral oil on 0000 steel wool makes a nice, comfortable edge. If you really need a deeper piece there to open up the finger/thumb gap, gluing in a strip of maple or ebony would do the trick. Just finish it round, polish with oil, and avoid having a massive muting chunk dangling from your fingerboard. Again, lighter is better, though I know there are those who adhere to fingerboard tuning ideas which might make for a bit more fussiness here...

powerbass said:
The other ideas are to remove all cross grain wood in the neck, tail and rib blocks.
Click to expand...

As above; proceed with caution, lest you introduce calamities in a dry spell by shifting cross-grain stresses to a more important interface. Things have been done this way for centuries for real reasons.

powerbass said:
The neck profile is flat where the thumb rests and the scroll will be simple w/out ornament.
Click to expand...

Really? This sounds profoundly uncomfortable if I'm understanding you, that the back of the neck is to be flat. The rounded back allows for a similar hand opening no matter which string is being played, as the hand rotates around the neck. A flat back would mean rather large opening of the hand for the outer strings compared to a narrow opening for the middle... unless one was to compensate by weird contortions in the arm/shoulder... or something. Just sounds weird, like you're trying to make a crude electric bass neck on an upright.
 

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