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DB Design -- Shape and Sound

Discussion in 'Basses [DB]' started by Mudfuzz, Sep 27, 2004.


  1. Mudfuzz

    Mudfuzz

    Apr 3, 2004
    WA...
    What effect does the size and shape of a bass's shoulders have on the overall sound of a bass?
     
  2. KSB - Ken Smith

    KSB - Ken Smith Banned Commercial User

    Mar 1, 2002
    Perkasie, PA USA
    Owner: Ken Smith Basses, Ltd.
    The Bass is still 'hollow' up to that point. It's all about air mass and air volume and the proportions of such. Ask Arnold to explain it better if this is not enough. I am sure others will throw their 2-cents in as well.
     
  3. Mudfuzz

    Mudfuzz

    Apr 3, 2004
    WA...
    This I know; but I was wondering if the air volume and if the tables have equal area from shape to shape, how does the actual shape of a bass effect the tone. ? Actually this question came into mind the last time you were talking about cutting down the shoulders of a bass; this has to change something.
     
  4. Aaron

    Violin acoustics nuts have done lots of research on the vibrational patterns of violin tops. Try the Catgut Acoustical Society webpage for articles about violin acoustics. The current thinking is that the shape of an instrument does affect the tone, in that the sound of said instrument will change noticably if you start cutting away at it. However you can't tell which of two instruments will sound better just by the shape alone. There are too many other variables. Obviously if you trim away a lot of an instrument's upper bout area, it will change the vibrational patterns of the top, so as to raise the frequency of the various top modes by some amount and also changing their relative strength. As you already know, lowering the internal volume while keeping the ff holes the same size will raise the frequency of the box slightly. and will lower the volume of the box resonance slightly.

    Hope this helps.

    Jon
     
  5. Mudfuzz

    Mudfuzz

    Apr 3, 2004
    WA...
    Also, another example that has me wondering about this is.
    In Peter Chandler’s book which I fond “interesting” it says
    Yet copies of other basses "mimic the acoustical character of the original".
     
  6. Mudfuzz

    Mudfuzz

    Apr 3, 2004
    WA...
    Thanks, it does.
     
  7. Aaron

    Yes, and he uses the same arching height on all the basses as well I believe. Interestingly most good basses fall within a fairly small range in terms of table thickness I am told. The internal volume of each of his models is obviously different, and the flat back of the Tarr must make a difference of course. Maybe it's how the Busan graduation lays out differently on different shaped tops that makes the difference, or it's just random luck based on the wood chosen and how each one is finally carved. He doen't mention tap tuning the plates like the best luthiers claim to do. It's mysterious. I wish some of our luthiers would get in on this discussion. Arnold? Bob?

    Jon
     
  8. AMJBASS

    AMJBASS Supporting Member

    Jan 8, 2002
    Ontario, Canada
    I agree with the possibility that you will raise the resonance frequency if you trim the shoulders.

    On another note....Peter Chandlers basses really sound so different from each other(and not always good) that I think the graduations should be done different for different basses/top wood. Some of his instruments are absolutely gorgeous, but don't have any volume or even tone to speak of, while some of the lesser instruments he has made sound really good. Keep in mind that bass making is a serious hobby for him and not a profession.
     
  9. KSB - Ken Smith

    KSB - Ken Smith Banned Commercial User

    Mar 1, 2002
    Perkasie, PA USA
    Owner: Ken Smith Basses, Ltd.
    Who is to say when a Bass is too big or too small unless you play it in perfect working order and then cut it down and test it again. When copying a pattern the wood will matter too, not just the shape.

    The Bass I am having cut has had a long rest. The Top and Back are in great shape for it's age but the Ribs have seen better days. Most likely they shrunk a bit and cracked due to the tight grain, Figure and un-flexible tight grained Top. The fact that the Bass hasn't been played in almost 100 years proves that it needs something to get it going again. I think playability make a big difference unless you want to start a Museum.......
     
  10. AMJBASS

    AMJBASS Supporting Member

    Jan 8, 2002
    Ontario, Canada
    Agreed. If a bass is unplayable there isn't much point in restoring it the way it is. I am sure a good deal of the great master basses were cut down at some point.
     
  11. Mudfuzz

    Mudfuzz

    Apr 3, 2004
    WA...
    I agree as well, if you can't play it, no one will hear if it sounds any good :D
     
  12. arnoldschnitzer

    arnoldschnitzer AES Fine Instruments

    Feb 16, 2002
    Brewster, NY, USA
    My $.02: Yes, shape affects tone. IMHO, the upper and lower bouts need to be in reasonable proportion, approximately a 2:3 ratio. Basses which have really sloped shoulders, even those with a huge lower bout, rarely sound deep or even. Basses with very large c-bouts, or c-bouts that curve in deeply toward the center, also can result in a smaller sound. I think that's because the lengthwise top vibrations are interrupted. Also, basses with very sharp curves can sound tight because the structure becomes too strong and does not resonate well. A cello shape would be ideal for tone, but basses made that way are very difficult to get around. Keep in mind that a perfect shape will not result in good sound if the materials, arching, construction or varnish are not well-executed. Sometimes a bass with a shape that seems "wrong" sounds great anyway, due to some mysterious confluence of materials, dimensions and workmanship.
     
  13. Chris Fitzgerald

    Chris Fitzgerald Student of Life Staff Member Administrator

    Oct 19, 2000
    Louisville, KY
    I've always wondered about this. In the Lemur catalog, there's a Pollman bass called the "Alexandria", which I find very appealing to look at, as it has extremely narrow shoulders and a large lower bout. (don't know if this pic will work, but here goes nothing...) I always wondered how it might likely sound.
     

    Attached Files:

  14. Chris Fitzgerald

    Chris Fitzgerald Student of Life Staff Member Administrator

    Oct 19, 2000
    Louisville, KY
    That pic doesn't really look like the one in the catalog, but it's sort of similar - if you have the cataolg, check out the "Alexandria" bass, and you'll see what I mean about the shoulders. In what way is that shape likely to affect the sound? Too thin? Too boomy? Too vague a question?
     
  15. KSB - Ken Smith

    KSB - Ken Smith Banned Commercial User

    Mar 1, 2002
    Perkasie, PA USA
    Owner: Ken Smith Basses, Ltd.
    The Cello Shaped Basses I have owned as well as the larger Upper Bout Basses I owned and Played (both) always sounded bigger and better as Arnold Described. This includes my Gilkes, and Martini (although sloped at the top is fairly wide) and previously owned Bernadel, Barbe, Old 18th century Italian (but labelled Rivolta 1822), and... a Forster (cello model) and two Guads. I played in NY.

    Although my Batchelder has a regular sized lower bout, the upper bout is bigger than usual and it sounds better than just about any Bass it's size I have come across.

    I think it's worth a little extra playing effort to get a better sound. With a smaller sloped Bass there is nothing you can do to bring out the tone if it's not there to begin with.
     
  16. godoze

    godoze

    Oct 21, 2002
    Chris, I too dig the "Alexandria "shape. Unfortunately I do not think much of Pollman basses.

    Ken you played Arnold's assymetrical bass; how does it compare to a "normal" bass tone wise ?
     
  17. KSB - Ken Smith

    KSB - Ken Smith Banned Commercial User

    Mar 1, 2002
    Perkasie, PA USA
    Owner: Ken Smith Basses, Ltd.
    Your'e putting me on the spot here Don. It was nice but not a huge Bass or a huge sound. It sounded better than most 3/4 new Basses I've tried. I was in a small showroom so the tone was more noticable than the volume as most Basses did fill the room. If I was ordering a Bass for Jazz or smaller Chamber type work, that Bass might suit me. If I was going for orchestra, I would go with his bigger model. Arnold knows alot about size and sound. His workmanship is beautiful as well. Not all pretty Basses sound as good as they look. Arnold's Basses had no problem in that department at all.

    I trust his judgement. That's why I left my Morelli there for restoration and a 'C' ext. as well.
     
  18. Often when we think of the "sound chamber" of the instrument we consider its vertical length and our thinking is that this is more important than the shoulders of the upper bout in determining the instrument's ability to support lower frequencies. A Georgia Tech physics professor pointed out to me that the longest continuous distance in the violin or similar instruments is diagonal (particularly if you subtract the end block area) and this diagonal is where the deepest tones will resonate the best.

    This tends to agree with the observations Ken S. and Arnold S. have made about "cello" shaped basses and the need to preserve some degree of roundness to the shoulders. I have seen one somewhat radical design (by a luthier I believe named Mark Richard who used to be in the Atlanta area) which (Arnold, you might want to take note since you are bold where innovation is concerned) increased the vertical cavity length by making the lower block pointed, with the endpin coming out of the point;- the ribs of the lower bout reverse curving down to make the point so the inner chamber was not interrupted at the bottom by the end block. I confess that I do not know how the bass sounded, I only saw an illustration of it. I do not know where Mark Richard currently resides unfortunately, but it was a very interesting looking bass and a clever variation on the usual design. ;)
     
  19. jlattuada

    jlattuada

    Apr 25, 2001
    Richmond, Va
    The Quenoil Style Bass that Rabbath plays has very small sloped shoulders. What are the general opinions on the sound that these basses produce?
     
  20. prelims222

    prelims222

    Sep 20, 2004
    Southeast US
    I hope I'm getting this correctly, but if you look at most violins, they have approximately equal volumes of air vibrating from the mensur marks down to the lower block as they do from the mensur marks up towards the upper block.

    I think this has a lot to do with why many great sounding basses have upper bouts that are a little tough to get around. But it doesn't mean all good instruments have big shoulders. As it has been noted, it is always a confluence of factors that determine an instrument's sound - I'd be curious to see a comparison of the volumes of air on either side of the mensur marks on a variety of great instruments, both old and new. I think that both quantity and relationship could be manipulated to influence quality of tone