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Hi there!I a thinking of trying a new two way adjustable truss rod.It is called hybrid and it is half titanium and half steel. Anyone using them?They weight only 70 gr. Do they affect the sound? Are they more ridgit?

I don't know anything about those truss rods but what I do know is that titanium is not as stiff as steel. Its stiffness falls somewhere between steel and aluminum and varies by the alloy. So unless it's larger geometrically it won't be more rigid.

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Jim Watts
http://jameswattsguitars.com

I have not used one of these rods. I see on line that there's a Hosco brand rod sold by a variety of sellers for $30-$37 plus shipping that is said to weigh 76 grams, providing what one dealer calls "an enormous weight reduction" compared to all-steel 2-way rods. The Martin 2 way rod I like to use weighs 135 grams and costs $8 plus shipping. Having a weight reduction of 60 grams might slightly reduce sustain and increase "punchiness," and affect other resonances, but this is hard to know. You could try temporarily adding 60 g (roughly two ounces) of mass to a guitar neck and seeing if you can hear any difference.

Another way to reduce weight is to go with a single-action rod, which many builders think is all that is needed.

People sometime switch out tuners to reduce weight and that can make a larger difference. Six open-back tuners can weight about 5 ounces, and big tuners like Grover Rotomatics can weigh over 9 ounces. Also, switching from metal to wood or plastic buttons can save you maybe an ounce and half. The weight of tuners is at the end of the neck and changes in tuner weight affect the feel of the guitar and the resonances in a slightly different way than a truss rod--resulting in better or worse sound? I doubt if anyone can say.

Personally, I'd rather have a truss rod well known to be reliable and save weight somewhere else.

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Tim Allen
"Never hurry, never rest."

The lowest 'neck' resonance (actually the whole guitar vibrating like a xylophone bar) can certainly produce measurable and audible effects on the sound of the guitar. To do this it has to match the'main air' resonant pitch quite closely, so that the two 'couple'. Normally the 'neck' resonance is around 65 Hz or so, well below the pitch of the 'air' at closer to 100 Hz, but if the neck is short and the head light the neck mode can be high enough. You don't see this often on steel strings (I think I've seen it once or twice) but it's not uncommon on classicals, and particularly on Flamencos with light weight friction peg tuners.

When the 'neck' mode matches the 'air' pitch the couple tends to 'spread out' the usual 'air' peak in the response. It's not as tall, and there's less of a chance of the usual 'wolf' note at that pitch (the dreaded 'thuddy G'). There actually seems to be more overall power available in that range, though. Often the bass timbre takes on a 'dark' quality.

Since the frequency match has to be pretty exact (.5 Hz or so) for this to work small changes in the weight of the head can make an out sized difference. It varies from one guitar to the next , in part due simply to the variation in stiffness and density of the neck wood. Swapping tuners, or even going to wood buttons from metal, can make enough of a difference sometimes to make the effect come and go, but it all depends on where you started out to begin with. That may be why some people notice a big change in the sound from such swaps, and others don't.

There are other 'neck'resonant modes at higher frequencies, but it's harder to say what effect they might have. They're more variable in pitch, for one thing, and there may not be ways for them to couple with part of the guitar that produce more sound. I don't think neck flexibility has as much effect on tone in an acoustic as it might in a solid body guitar: the neck is the most flexible part of a solid body, where on an acoustic it's the top.

Thanks alot for your replies! After all that being said i will stick with a common steel truss rod....

Titanium is among the metals that are prone to "galling", so if the rod uses a threaded titanium rod it may become a "single acting rod" - which is to say it may only work once before the threads gall and the rod locks up. . Maybe that won't happen if it is adjusted carefully and slowly, but I have had that happen with fine thread stainless fasteners just turning them by hand with an allen wrench.https://www.boltdepot.com/fastener-info ... lling.aspx
Rigidity is not a great concern for truss rods, in fact you don't want them to be too rigid. If they couldn't bend they wouldn't work. Someone once proposed using a piece of wire as a single action truss rod, which would be very lightweight, but I don't know if anyone actually tried it.

Years ago, at the Sho Bud store in downtown Nashville, the Baker Piano Company sold guitars that they built. The "Baker Piano Guitars" had a piano tuning pin in the middle of the peghead, and a piece of piano wire running through the neck, anchored to a screw in the headblock. Not very elegant, but I suppose it worked.

https://www.ebay.com/itm/353254443278?ViewItem=&item=353254443278

Dave

Neat!

Thank you all for thw replies!!