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physics behind bolt-on vs thru-neck

Discussion in 'Luthier's Corner' started by wrench45us, Jan 18, 2012.

  1. wrench45us


    Aug 26, 2011
    so in expanding my knowledge, I've read in a few places now that bolt-on necks are 'punchier' and a few other adjectives than thru-necks, my question is what's the sound generation physics behind the difference.

    My sense would be a thru-neck would have a potentially smoother waveform. but what do I know?

    There seem to be 3 variations, the pure bolt on, the pure thru-neck and the epoxy fused neck to body, so what are the general sound differences and the physics behind those differences.
  2. Musiclogic

    Musiclogic Commercial User

    Aug 6, 2005
    Southwest Michigan
    Owner/Builder: HJC Customs USA, The Cool Lute, C G O
    actually there are a few more neck options than that, and not many people use epoxy to do a set neck due to the rapid shrink epoxy is known for as compared to Alaphatic resin and hide glue.

    I won't comment on sonic properties, as it's a hornets nest of myth and perception, that many are devout about and rarely know anything more than supposition.
  3. wrench45us


    Aug 26, 2011
    I suspect I read resin and mis-classified that into more familar category of epoxy. It was a material that could be worked/sculpted -- when cured.
  4. The truth is, nobody knows. I've had 'punchy' neck-throughs and 'sustain-y' bolt-ons. Trouble is, when you change from one construction method to another, you change significant design elements of both the body and neck. So who's to say where the (alleged) differences may come from?
    I'll tell you this though, as an experiment I once glued the neck of a bolt-on bass into the neck pocket to see if I could detect differences in tone or sustain, or whatever. I could not.
  5. ctmullins

    ctmullins fueled by beer and coconut Gold Supporting Member

    Apr 18, 2008
    MS Gulf Coast
    I'm highly opinionated and extremely self-assured
    All generalizations are false. Including this one.
  6. Musiclogic

    Musiclogic Commercial User

    Aug 6, 2005
    Southwest Michigan
    Owner/Builder: HJC Customs USA, The Cool Lute, C G O
    LOL Todd
  7. Pep

    Pep Supporting Member

    Oct 5, 2010
    Louisville, KY
    After playing bass for nearly 50 years, I can't give you a definite answer. On several occasions I've even had two identical basses (same materials, electronics, hardware and strings) and they sounded and responded differently.

    I don't believe it's as much how the neck is attached as much as it is the materials used.

    With that I will shut up because I could dig myself into a deep hole and well, . . . . . . . . you know. ;)
  8. wrench45us


    Aug 26, 2011
    certain properties difficult to quantify

    I was expecting more science than art, but there you go.
    I'm sure there's data somewhere that supports certain conclusions; it must be that there are just so many factors involved that any sound quality has considerable overlap -- not to mention subjective bias.
  9. colcifer

    colcifer Esteemed Nitpicker Supporting Member

    Feb 10, 2010
    A Galaxy Far, Far Away
    I'll take a stab. You owe me one as I'll have to go into hiding after hitting 'reply.'

    The idea behind the solid body design is, IN PART, to minimize the amount of string vibration absorbed by the instrument, maximizing sustain, among other things. The bolt on (screw on, actually) neck joints on Fender are to make servicing easy. Neck-through design is takes the joint out of the picture which means one less sink hole for string energy. The success of this, generally speaking, has more to do with build quality than design. YMMV :bag:
  10. wrench45us


    Aug 26, 2011
    that offers some reasonable physics in theory an dpractice

    good enough to offer a span of online sanctuary
  11. shai-ga


    Dec 31, 2006
    New Jersey
    Some facts related to this subject:

    Jens Ritter is a mechanical engineer..
    He chooses bolt-on construction. I read about some experiments he made.. which led him to use about 10 screws per neck.

    Michael Tobias used to build basses with neck thru layout, then moved to bolt-on.

    Personally, I prefer the idea of having two pieces - neck and body, instead of gluing it up.
    + some luthiers say that neck thru is too sterile sounding.
  12. cnltb


    May 28, 2005
    Some more "facts":
    Wood for bolt on necks is cheaper as one doesn't need pieces that are quite so long.
    Bolt on is easier to repair.
    Often it's also easier to build in some cases and tolerances are not quite so tight (I am not sure on the tolerances but was told so some time ago.)

    I think that one can get quite close to neck through behaviour on a bolt necked bass, depending on the neck pocket and the joint in general. A deeper pocket seems to help, if that's what one is after.
  13. Dirk Diggler

    Dirk Diggler Supporting Member

    Mar 3, 2004
    Anytown USA
    Personally I feel it in my hands more than hear the differences. And IMHO it's all about cost, Re: Tobias, he also started making imports too.
  14. shai-ga


    Dec 31, 2006
    New Jersey
    All of the neck thru basses I've played felt smoother to the hands and ears,
    like a creamy feel, in a good way..
  15. I can't tell the difference in tone or sustain between the bolt on vs neck thru

    I do like the look and feel of bolt on much better

    Bolt on looks rugged, not dainty
  16. pilotjones

    pilotjones Supporting Member

    Nov 8, 2001
    If I remember the Tobias interview correctly, he said that there are tonal differences, and that he moved to bolt-on construction to get the tone that matched a shift in market desires.
  17. does anybody have a copy of American Lutherie #91, from 2007 lying around? Apparently there's an article in it touching on the subject.

    Lutherie Myth/Science: Neck Joint Type and Sustain

    To be honest, I'm in the "whatever difference it makes, it's going to be minimal" camp. I have no real preference for either, and I'm not sure I'd be able to tell the difference between two otherwise identical basses. I do think that Colcifer's comment makes a lot of sense theoretically, but before making any real statement/argument I would like to see some numbers. It's easy to get caught up in details - ash vs. alder vs. mahogany, various pickup brands, brass vs. steel hardware, high-mass bridges vs. the fender standard bridge - the problem with this thinking is that it can sometimes overlook the final product in favour of what it's made of.
  18. gitlvr


    Nov 13, 2009
    No. Va., USA
    I don't know about tone, and like others have stated, that's a deep pit that I'm not willing to climb down into.
    But to me, I like both bolt on and set neck(don't have any experience playing or building neck through), and enjoy building both. They each have advantages to the builder. In the case of bolt on, there's less hand fitting of the neck joint versus the set neck, and it's much easier to replace the neck if damaged.
    For me, the appeal of the set neck is in the build. I love carving tops, which is part of the build for me with set necks. There's also, at least for me, an elegance to the design of the set neck, From the carving of the top to the planing in of the top from bridge to the neck end of the body to match the set of the neck and the actual fitting of the joint itself, IMHO it's a more graceful design. More like art to me than a bolt on build. But I love building both. That's my personal take on it. YMMV, and probably will.
  19. Grooveman1961


    May 8, 2006
    I think that there is some exact science out there. Go and find the alembic forums. This topic comes up now and then. The concensus there seems to be that neck through attenuate highs and lows less. Bolt ons may sound punchier because their mids are more pronounced. Find stuff written by the Wickarshims, Rick Turner. They really geeked these concepts out and understand them well.
  20. Grooveman1961


    May 8, 2006
    Heres a post by Mica Wickersham from the alembic club:

    Bob, we're not huge midrange fans in band settings. The traditional Tom Walker design does quite nicely, even with with a neck through Alembic bass. We've got thousands of happy customers with this pairing, so there are some that share this opinion. It won't suit everyone's taste, and there are a variety of different ideas out there when it comes to preamps. When playing at home, many people miss the rest of the band, and pump up the mids when practicing.

    I find that bolt-ons have less sustain overall, affecting all frequencies. Bolt-ons with a stronger, better fit joint improve sustain and frequency response, and a glued joint brings the two pieces together even more completely. Material choices impact the sound even more on bolt-on and set neck designs.

    The skill of the fret installation and the setup work can have an impact on sustain as well.

    Dense woods tend to emphasize high frequency response in Alembics. The shorter wavelengths can course through the tightly packed cells. Less dense woods emphasize the low frequencies on Alembics, where the longer wavelengths have room in the larger more open cells. The neck through construction still results in an predictable EQ "smile."

    For instance, a Maple (dense) body Alembic neck through, like an Elan or original Essence, has a very bright sound. An original Spoiler, with a solid Koa (less dense) body produces a much warmer sound emphasizing lows. Both examples have the same neck construction and materials.

    The basses we've made with Alder, a fairly traditional bolt-on wood, seem to have limited high end response when used on Alembics, producing an overall "thunky" sound. Ash for bodies seems to keep the midrange more active, even on Alembic neck throughs, but the smile persists.

    With the personification of "eating" the mids, it's less important if they are lower or if the bass and treble is higher, the resulting sound is still one of an EQ smile on a neck through. If someone wants more mids, and a punchier sounding Alembic, I'll suggest a set neck construction so they aren't fighting the nature of the bass. There are many individual players capable of making a neck through sound plenty punchy through technique, but not every player has that at their disposal.

    I'd also suggest that bolt-ons are less expensive to produce. If the neck or body fails, you can replace that part. On a neck through, it's a much more expensive task to salvage a body or neck. It takes us at least 10 hours more to produce a neck through over a set neck.

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