why is the Gibson TOM bridge slanted

Discussion in 'Tele Home Depot' started by papaschtroumpf, Sep 26, 2016.

  1. papaschtroumpf

    papaschtroumpf Tele-Holic

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    I was looking at a Les Paul style guitar this weekend and noticed the bridge is not parallel to the tailpiece (or the pickups for that matter), the bass side is further away from the pickup.

    [​IMG]


    I thought proper intonation was when the center of the string is on the 12th fret, but by moving the bass side away, aren't you making the saddle further away than the distance between the nut and the 12th fret (whcih are parallel to each other)?
     
  2. DrASATele

    DrASATele Poster Extraordinaire

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    It's a form of compensation.
    Each string doesn't intonate at say 25.5 (just picking that as an example) there are factions of that number spread out over all the strings on the guitar. Then add the radius of the fret board and the push back on the lower strings is to give your saddles enough wiggle room for pitch.
     
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  3. John Nicholas

    John Nicholas Friend of Leo's

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    ^ What he said!
     
  4. papaschtroumpf

    papaschtroumpf Tele-Holic

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    which is not much of an explanation. what is it compensating for? I'm trying to understand the reason why it needs compensated. It seems that to be intonated right, the distance from the 12th fret to the saddle needs to be slightly longer than the length from the nut to the fret. My only guess is that the downward pressure puts more tension on the fret?
     
  5. papaschtroumpf

    papaschtroumpf Tele-Holic

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  6. telemnemonics

    telemnemonics Doctor of Teleocity Ad Free Member

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    String length, mass, and flexibility all influence what frequency a given length and tension of any material vibrates at.
    Our particular wish to have fat multi part strings behave the same as thin one part strings is just a wish.

    The bridge doesn't have to be slanted but it would have to be wider to allow enough adjustment range to satisfy our wishes that physics alone will not do for us.
     
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  7. WallyD

    WallyD TDPRI Member

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    To help with intonation. With the adjustable saddles I wouldn’t think it would really matter but what do I know?
     
  8. guitarbuilder

    guitarbuilder Telefied Ad Free Member

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    Proper intonation is dependent on action and string guage for a given scale length. With the Gibson style ABR-1 bridges, the saddles couldn't be adjusted back far enough on the bass side to compensate for the larger guage strings commonly used, so they slanted them. In some cases this still wasn't enough and bridges had to be remounted by a tech. I had a friend who needed this done on his ES-335. The abr-1 bridge evolved to the Nashville style with a longer saddle travel as a result.
     
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  9. Ripthorn

    Ripthorn Tele-Afflicted

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    The standard TOM bridge does not have sufficient saddle travel to correct for typical intonation needs, so it is angled to give the bass saddles more "range" from the 1/2 scale length distance.

    As for "what are we compensating for", there are a few factors that need correcting. One is definitely the fact that as you depress a string, the increase in tension results in a slight increase in pitch, which requires moving the saddle back. Additionally, the bass strings, because of their construction, tend to require more compensation. If you look at the physics of a string, the cross sectional area affects the elasticity of the string. It also has a greater mass density, which plays a factor in the vibrational frequency. Finally, because the bass strings deal with lower wavelengths, a proportional change in tension will result in a longer absolute length needed for compensation.

    So in short, you are compensating for all the things that freshman physics leaves out :) I am acoustic physicist, so this type of stuff is not only something that I love, but I've got a lot of years invested in it. Physics rules, but any system is so much more complex than we like to usually admit.
     
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  10. TenaciousP

    TenaciousP Tele-Meister

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    It's the same reason the saddle on an acoustic bridge is not parallel with the edge of the bridge. The larger strings require a longer vibrating length to intonate properly. A TOM doesn't have enough travel in the adjustable saddles to intonate the bass strings without the body of the bridge being angled farther away from the nut. The reason for the intonation issue is a matter of complicated physics. The theoretical scale length of 2x the distance from nut to 12th fret doesn't really work out right in real life.
     
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  11. jackinjax

    jackinjax Friend of Leo's

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    WP_20151004_07_48_08_Pro.jpg Here's a picture of my LP. Notice that all the saddles are adjusted fully forward and still wouldn't intonate. Come to find out, the bridge was factory installed nearly 3/8" too far back. The tech told me I'd have to have the bridge removed, holes filled, and re-drilled in the proper location. I didn't want to screw up the finish of an otherwise beautiful guitar, so I searched until I found a roller bridge from Stewmac that had elongated screw holes the allows the bridge to move forward or backward 3/8". Problem solved.
     
    Last edited: Sep 26, 2016
  12. telemnemonics

    telemnemonics Doctor of Teleocity Ad Free Member

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    It's worth noting that originally many or most string instruments had straight wood bridges held to the top by string tension, and moved to wherever gave the best intonation if the instrument was fretted. Inevitably at an angle.
    The LP design team came from that perspective.
    Everyone else seems to have followed the Gibson idea, maybe just so they could use the same parts.
     
  13. TenaciousP

    TenaciousP Tele-Meister

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    Looks like I was a little too slow posting my reply. Your explanation is more detailed than mine though. :)
     
  14. jackinjax

    jackinjax Friend of Leo's

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    Couldn't get both before and after photos to load. Below is the after pic.
    IMG_20160926_1804390_rewind.jpg
     
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  15. telemnemonics

    telemnemonics Doctor of Teleocity Ad Free Member

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    The only problem with the idea that the angle is due to the width of the bridge is the fact that the bridge was designed for the application.
    The choice to angle the bridge was not determined by the width of the bridge, the width was determined based on the presumed angle.
     
  16. Ripthorn

    Ripthorn Tele-Afflicted

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    I am not a Gibson historian, so that may well be true. That being the case, it may have been because the wrap tail piece on a '53-'55 was angled that they decided to keep the aesthetic. It remains today, though, that there is insufficient travel to compensate appropriately without angling the bridge, regardless of whether that was design intent or not. Some newer bridges like the Schaller signum are meant to mount straight.
     
  17. DrASATele

    DrASATele Poster Extraordinaire

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    +1 on all of this... which I was trying to, unsuccessfully so, condense into a few sentences.
     
  18. buffalohunt

    buffalohunt TDPRI Member

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    Check this out.. It might not be the easiest fix, but a good idea for vintage instruments.

     
  19. jackinjax

    jackinjax Friend of Leo's

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    Thanks, I had seen this video when I was searching for an adjustable position bridge, but, though I have a garage full of power tools, a lathe isn't one of them.
    Evidently it's not a common problem with modern day guitars. I even wrote and sent pictures to Gotoh and a couple of other hardware manufacturers. The president of Gotoh wrote back and said he'd have his engineers look into it. That Stewmac, noname bridge was the only simple solution I could find.
     
  20. jayyj

    jayyj Tele-Afflicted

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    The bridge is angled on vintage style Gibsons so that you already have an approximate intonation (as you have on an acoustic with an angled saddle) from the angled bridge with the saddles in the middle, so the saddles themselves are intended to fine tune the intonation for each string depending on pitch, gauge and construction.

    If you use a straight bridge and let the saddles do all of the work you end up with a huge bridge - the bridges nicknamed harmonica bridges from the 70s are like that.
     
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