Graphite vs. Titanium neck reinforcement

[Gilmourisgod]

The only down side I can see to the combination of two graphite rods either side of a single DA trussrod is the potential effect on minimum neck depth. From what I've read on TB, most builders regard around 3/32" to 1/8" of wood under the deepest part of the trussrod to be absolute minimum to prevent it blowing out. I have probably erred on the side of caution maintaining a full 1/8". The graphite rods I have used are 1/8" thick x 3/8" deep, so they don't really enter into the neck profile equation unless you are doing some kind of bizarre hard "vee" shape. @Bruce Johnson has some pretty convincing theories on neck stiffness using a proprietary truss rod design and ins some cases a "back strap" of carbon fiber TOW strands set in epoxy. I have an open mind on the subject, curious to hear if any real consensus on this is developing.

 

[Killed_by_Death]

Not sure why the "industry" is calling them "rods" when they're clearly bars:

 

[jeff62]

Ti is heaps harder (10x) than Graphite, but I'm not finding specs on stiffness.
Graphite is almost half the density of Ti.

When I've seen demonstrations of resonance the lecturer will strike the material & let the user listen to it.
In the case of Ti you'd get a clear ring, there are even huge bells made of Ti, but in the case of soft Graphite...

I'm no scientist (I play one on TV! ) but the way I think of this is, aside from mass (of the truss rod) which may or may not have it's own affect on what we hear, that we are adjusting the truss rod to achieve the desired bow of the neck - and this requires a specific amount of tension from the rod. Point is, I would question that stiffness of the material matters since once the tension is placed on the neck, we have a "system" that operates the same regardless of the inner material.

If the mass of the rod has some other affect, so be it. I've heard many people say that their 13-lb Jazz bass blows away their 9-lb Jazz bass. Maybe. I've also heard 8-lb basses that blow away 13-lb basses. That alone tells me that mass is either not a defining factor in sound, or at least not a significant factor.

 

[Killed_by_Death]

it's the stiffness that matters, more than density

 

[Gilmourisgod]

Everyone knows that Tone Bars are better than plain old Titanium because they are .....tonier. I wonder if they actually have that logo etched into them, and if anybody is willing to cut up a neck to find out. This is the kind of question that keeps me up at night.

 

[Killed_by_Death]

Ever since this thread when someone mentions their instrument resonates so well I start shaking my head. So you like those dead spots?!

 

[Gilmourisgod]

I must be dead spot tone deaf, none of my basses seem to have one. Maybe I should plug into a frequency analyzer so I can figure out what I’m supposed to be obsessing over. I’ll admit I drank the Coolaid on graphite bars, but so far they seem to be working to keep my neck builds (all two of them) stable. As to influence on tone, I’m sceptical at best, but who knows, my scientific sample set of (2) is..... inconclusive.

 

[Killed_by_Death]

I'm feeling like a bit of maroon right now for not seeing the experiment I "could have" done with the different Standard Soundgears basses I've moved through here since owning my Premium with the Titanium reinforcement bars.

 

[foothilla]

Ever since this thread when someone mentions their instrument resonates so well I start shaking my head. So you like those dead spots?!

If resonance is the enemy, then someone should dig up Mr. Stradivari and tell him that his violins are deadspot magnets.

 

[foothilla]

The violin's resonant frequencies are actually non-Musical tones.

Oh yea? What about acoustic guitar? Upright basses? Ukes? Mandolins?

Also non-musical tones?

 

[ctmullins]

@foothilla, the physics definition of “resonance” is basically “frequencies which are absorbed by a structure”. Because most physical structures are not 100% stiff, there is some absorption of vibrational energy, and this happens more at certain frequencies than others.

If a luthier’s goal is to faithfully transmit the sound of a vibrating string, then that luthier will want to create a structure that absorbs the least amount of string energy, so that it can be transmitted to the air or pickups.

Resonance = deadspots.


Edit, after a bit more musing: You may be right, at least regarding acoustic instruments. Most of my time is spent with electric instruments, and I still maintain that electric instruments do not benefit from resonance. You (well, me anyway) want the pickup to sense the full and free spectrum of energy from the vibrating string.

But acoustic instruments are different. An acoustic instrument works by the vibrating string transmitting its energy to the structure of the instrument, which then (if it’s constructed properly) re-transmits that energy into the open air through Helmholtz resonance. So here we do want the structure to absorb string energy, and then we also want that structure to be able to send it back out. If an acoustic instrument does not do this efficiently (for whatever reason), then it’s still wasting string energy, which is undesirable.

 

[foothilla]

@foothilla

If a luthier’s goal is to faithfully transmit the sound of a vibrating string, then that luthier will want to create a structure that absorbs the least amount of string energy, so that it can be transmitted to the air or pickups.

Resonance = deadspots.

And how is that accomplished in acoustic instruments, where it is unavoidable to have the woods absorbing energy??

 

[ctmullins]

And how is that accomplished in acoustic instruments?

I was editing my post when you posted; see above.

 

[foothilla]

I was editing my post when you posted; see above.

If what you are saying is accurate, every stringed acoustic instrument would be loaded with dead spots.

 

[ctmullins]

Well I thought this was pretty simple:

• Resonance = energy absorbed by the structure
• For an electric instrument, energy absorbed by the structure = energy not available to the pickup = dead spot
• For an acoustic instrument, energy absorbed by the structure should be re-transmitted by the acoustic chamber(s) in the body
• For an acoustic instrument, energy absorbed by the body and not re-transmitted acoustically = dead spot

Also, perhaps it bears mentioning that many lay-people use the term “resonance” to mean “I can feel the string vibrations through the body”. That’s totally different.

To sum up, energy lost = bad.

Edit: This is intentionally over-simplified. The truth is that no instrument made of wood is infinitely stiff, and therefore they all absorb a (hopefully) small amount of string energy. This is actually at the heart of what we call “tone”. An Alembic is not completely stiff, but very stiff, and does not absorb very much string energy, which gives it that full-frequency “piano” tone. At the other extreme, a full-size double bass, with its large and somewhat flexy body, absorbs a significant amount of string energy, which is what causes its characteristic decay envelope (combined with string choice, of course). This is where the real luthiers outpace us slab-body hacks. People with far more talent, skill, and experience than me know how to build an instrument that absorbs the right amount of string energy to achieve a certain tonal goal.

 

[Killed_by_Death]

it bears mentioning that many lay-people use the term “resonance” to mean “I can feel the string vibrations through the body”. That’s totally different.

That was my point earlier. A local guitar player posted a review of his latest acquisition & used the term "very resonant", which had me shaking my head.
Almost everyone confounds vibration & resonance.

It wasn't quite as bad as the guy who posted his Ibanez Talman & when asked if it had active pickups, he responded that it does
The Ibanez Mikro in the room with me has the same Dynamix pickups & the bass has no battery, it is 100% passive!

 

[Gilmourisgod]

I’m a believer in the “stiffness/softness” ( that sounds wrong somehow) as determinant of how much energy stays in the strings, but since every piece of wood is effectively unique, I’m sceptical you can predict what any assembly of wood pieces will do as a system, beyond generalities like “maple is usually stiffer”. Alembics are truly works of art, but I get a kick out of their descriptions, which read like recipes for wine tasters, as if that hint of ebony with notes of vermillion could “tuned” to produce a specific audible tone. For stiffness and resistance to environmental factors like humidity, I’ve never seen anything that remotely rivals graphite/carbon fiber, so obviously these attributes aren’t the primary concern in modern bass design. People like stuff that looks great, and often “hear” with their eyes.

 

[foothilla]

Well I thought this was pretty simple:

• Resonance = energy absorbed by the structure
• For an electric instrument, energy absorbed by the structure = energy not available to the pickup = dead spot
• For an acoustic instrument, energy absorbed by the structure should be re-transmitted by the acoustic chamber(s) in the body
• For an acoustic instrument, energy absorbed by the body and not re-transmitted acoustically = dead spot

Also, perhaps it bears mentioning that many lay-people use the term “resonance” to mean “I can feel the string vibrations through the body”. That’s totally different.

To sum up, energy lost = bad.

Edit: This is intentionally over-simplified. The truth is that no instrument made of wood is infinitely stiff, and therefore they all absorb a (hopefully) small amount of string energy. This is actually at the heart of what we call “tone”. An Alembic is not completely stiff, but very stiff, and does not absorb very much string energy, which gives it that full-frequency “piano” tone. At the other extreme, a full-size double bass, with its large and somewhat flexy body, absorbs a significant amount of string energy, which is what causes its characteristic decay envelope (combined with string choice, of course). This is where the real luthiers outpace us slab-body hacks. People with far more talent, skill, and experience than me know how to build an instrument that absorbs the right amount of string energy to achieve a certain tonal goal.

I don't argue the most of what you are saying. I am arguing your clear statement of "Resonance = Deadspots", which is completely inaccurate. Every wooden, stringed instrument inherently deals in resonance. Yet, I could provide you with wooden, stringed instruments where you couldn't find a dead spot if your life depended on it. Therefore, resonance does not always result in audible deadspots.

Secondly, I would argue that amplified instruments are far less susceptible to debilitating deadspots, because you are not dependent on your vibrating, resonating tonewoods also acting as amplification. It's common to hear a deadspot on an unamplified electric instrument, that you don't even notice once you're amplified (unless you have a weird style with lots of long, sustaining notes). Whereas an acoustic instrument with deadspots can't be saved by the magic of amplification.

 

[ctmullins]

Gotcha. Perhaps it’s a matter of degrees? Whatever units the magnitude of resonance is measured in. I think I’m getting somewhat out of my depth here, but I think a dead spot is a frequency with “a lot” of resonance. ?? Whereas other resonant frequencies could be less severe, and not noticeable as a true dead spot. ??

I think I need a structural engineer. @pilotjones , are you still around?

 

[BurningSkies]

I'd love to have a bass that can have the relief set and not heed any atmospheric changes ever again. If that's TI vs. graphite, whatever. As I've been playing more and more fretless, I'm convinced that having the ability to dial in a really low precise action with a specific amount of relief and be able to have the board trued precisely would make for the best fretless experience possible.