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All The Different Spiros Sets

Discussion in 'Strings [DB]' started by iiipopes, Dec 26, 2010.

  1. iiipopes

    iiipopes Supporting Member

    May 4, 2009
    With all the TI Spiros sets, TI has, of course, put them all in a pdf so we can compare tension and length specs.
    http://www.thomastik-infeld.com/upload/TI_bass folder 03_07print.pdf
    But, each tension, of course, is for its particular original application: S42 for 4/4 110cm scale, 3885 for 3/4 106 cm, etc. So to get a true comparison, I downloaded the chart, did the math, and came up with the comparative tensions if each were installed on a 106cm, 41.73" scale bass. I didn't do the 1/2 sets or the 1/4 set, simply because the strings just aren't long enough. For example, we all know that installing a solo set at orch pitch is softer -- this chart tells how much softer. Also, it might help in choosing, for example, a different "G" string so it doesn't whang, but is still in the tension ballpark. And now you know just how stark an E stark really is.

    Comparative Tensions of Different Sets of Spirocores,
    If Each Were Installed on a 3/4 106 cm (41.73 inches)
    Mensure Bass at Orchestra Pitch (all in pounds)
    			G	D	A	E	Total
    S42 4/4 Light		55.2	59.3	61.4	63.4	239.3
    S42 4/4 Medium		61.4	65.8	69.6	69.6	266.4
    S42 4/4 Heavy		73.7	73.7	75.8	77.8	301.0
    4/4 Solo @ 3/4 Orch	55.3	55.3	55.3	56.9	222.8
    3/4 Solo @ 3/4 Orch	56.0	57.8	57.8	57.8	229.4
    3885 3/4 Light		60.6	61.7	63.9	66.1	252.3
    3885 3/4 Medium		67.2	68.3	70.5	72.8	278.8

    Stay tuned for a 5/8 102cm/40.16" chart!

    Attached Files:

    RBrownBass likes this.
  2. Eric Hochberg

    Eric Hochberg

    Jul 7, 2004
    Excellent, thanks!
  3. iiipopes

    iiipopes Supporting Member

    May 4, 2009
    Thanks to Francois, who took my raw data and put it in table form!
  4. Dr Rod

    Dr Rod

    Aug 19, 2005
    this is truly excellent, thanks so much

    it shows a considerable tension difference between 3/4 and 4/4 sets within the same category, so actually we have two different tensions to choose from for lights and mediums
  5. iiipopes

    iiipopes Supporting Member

    May 4, 2009
    One thing that I noticed was the difference across the board for "regular" sets verses solo sets. The "regular" sets generally have increasing tension as you go down in order to get more response out of the instrument to support the ensemble better as pitch descends, while the solo sets are made with a more even tension across the board to get consistent feel.

    This is in direct contrast to EB stringmaking, where the low E string is usually of lesser tension in order to maintain flexibility and consistent tone from string to string, leaving support of the ensemble to the amplifier and its tone controls.
  6. iiipopes

    iiipopes Supporting Member

    May 4, 2009
    EDITED CHART -- caught some typos.
  7. engedi1

    engedi1 Supporting Member

    Sep 16, 2005
    Great work. Thanks!
  8. DC Bass

    DC Bass Supporting Member

    Mar 28, 2010
    Washington DC

    Good stuff! Thanks for taking the time!

  9. iiipopes

    iiipopes Supporting Member

    May 4, 2009
  10. Sam Dingle

    Sam Dingle Supporting Member

    Aug 16, 2011
    Is there a way to tell if we have the 4/4 medium or the 3/4 medium? I hear if you put the 4/4 on a 3/4 bass there's a little less tension. This true?
  11. BobKay

    BobKay Supporting Member

    Nov 5, 2012
    Estero, Florida; USA
    I'm not familiar with string tension technology. What is the unit of measure for string tension? Pounds/inch? Kilos/cm?

    Just an idle question; not even sure how to use the information.
  12. BobKay

    BobKay Supporting Member

    Nov 5, 2012
    Estero, Florida; USA
    Sorry - just noted the legend at the top with "pounds."
  13. Kai Sanchez

    Kai Sanchez Supporting Member

    Sep 12, 2006
    At least on my bass I confirmed this, there's more tension on the 3/4 weichs compared to the 4/4's. I went from 4/4 Spiro Mediums (that were choking the sound of my bass) to 3/4 weichs and the bass opened up. Then I got curious about the 4/4 weichs and found the G string too thin, and the whole set too loose and unfocused. The bass opened up even more with the 4/4 weich set but the pitches weren't focused enough for my taste. Went back to ny old 3/4 set and the pitches are very clear and the tension does not bother me.
    Steve Boisen likes this.
  14. They differ in length and weight per (playable part) length unit (but hard to measure without cutting the string into pieces).

    But because the different pitches of one set differ in length too, we need some reference for each string of the 3/4 and 4/4 sets.

    I 'm working on a database of my strings with as much information as possible (including measured tension on 105 and 110 cm scale and string length information) but since this is a lot of information to measure and collect (and the layout of the database needs to be adapted to different string lengths for different pitches) and I'm overly busy with other stuff for the next months (maybe years) so I doubt I can give you the information you need. I only have one measurement of a string length at the moment (I'm currently more interested in string tensions).

    BTW, the tension is constant independently of the length of string . The elongation of the string (because of the tension) IS dependent on the length of the string.
  15. richhansen

    richhansen Supporting Member

    Oct 2, 2006
    Endorser of the KSM Foundation Bridge.
    This is very useful information, so thank you guys for doing this. One point that I'm confused on, is the 3/4 vs. 4/4 tension. Wouldn't the longer bass (4/4) require a string with more tension to make it sound and play with the same tension as a 3/4 bass? It seems like simple physics. Slab basses have thinner strings with less tension and less diameter than an upright. Why would the 4/4 strings strung on a 3/4 bass have less tension overall in your table? It seems like the opposite should be true.
  16. I think that if you put the 4/4 string on a 4/4 sized bass you would get higher tension. That information is on the TI website, I believe. If you put that same 4/4 string on a 3/4 size bass you will get less tension than on the 4/4 size instrument. Does that make sense? I think I understand this stuff but it's hard for me to articulate it sometimes...
  17. Reason being, I believe, is that generally a shorter string length equals less tension, so a string meant for a bass with a 43" string stop will have lower tension at 41".
  18. 3/4 and 4/4 Spiros are made for the same tension, but on different vibrating string lengths. If you tune a 4/4 string on a 4/4 scale and grip with your finger where the 3/4 scale ends (about a halftone), then you get a higher pitch. Tune the string down to get the same pitch as on the open string before and the tension goes down. <that's what happens on a 3/4 scale woth a 4/4 scale Spiro string.
    This is only because the string are made by Thomastik to get the same tension on their intended vibrating string lengths (which are of course different).

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