single vs double truss rod

[vtpcnk]

guys what do you think about the double expanding rod of warmoth's pro necks?

warmoth lists as advantages for the double expanding rod :

-Extremely stable, no seasonal adjustments are necessary
-Increased mass = longer sustain, cleaner and clearer notes
-No end to end wood compression to eventually distort the neck
-Top adjusting on 13° Angled necks


does anybody have any personal experience comparing necks of single and double truss rods for the above factors?

i read on the net a claim that the double truss rod actually degrades the tone. any views on this?

and haven't companies like gibson, fender etc been using the single truss rod for ages without any major known issues?

are there other major guitar companies which use the double truss rod?

appreciate any insights.

 

[blue313]

http://www.fender.com/support/faqs.php#q12

 

[Dan025]

the warmoth truss rod is diferent from the fender biflex rod. i haven't seen the device before it is put in and i don't think the pictures show enough detail. both my warmoth necks are pro construction and have the double adjustable truss rod. is there a diference in tone, i bet there is but i cant here it. it is absolutely stable. that is a fact. it might not suit the purists but i'm not a purist. it is the same in many circles, people don't like change. we all know that the 50's and 60's fender and gibson guitars were amazing in there own time but many have this illusion that they were perfect. i know some modern instruments are inferior in some ways but many are far superior. the original fender formula worked and some are just afraid to stray from that. anytime someone says something that is older is better you have to take it with a grain of salt. see if there are any actual facts behind it. im not sure any actual research has been done to see how the new truss rods actually change tone.

 

[-CB-]

All "double expanding" rods pretty much work the same way.  There is a threaded rod, and a non threaded bar.  The threaded rod has threaded ferrules that it screws into.  The ferrules are permanently connected to the bar.  It goes in a flat channel in the neck, not a curved one.  The "curve" comes from pulling on the bar from both ends, causing it to bow.  Its not a totally different situation than you'd see on a simple bow and arrow's bow.  You make the string shorter, and the bow flexes more.  In this case, you turn the threaded piece, the ferrules get closer together, and you make the bar flex.  That flexing pushes on the wood in the neck, and the neck gets a boost to counter the effect of the string pull.

Thats pretty much how the bi flex and the double expanding work.... with very slight variation