Anybody remember these? They were all the rage for a while. No idea if they actually did anything aside from promoting neck dive, but they looked sorta cool. 
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Stiffening Rods and Dead Spots
- Thread starter Old Fart
- Start date
I'm going to have to blatantly steal that Sciency term now. Sorry, not Sorry. "Honey, I'm off to the shop, gotta adjust the Groove Modulus on my Ric Clone".
can't read the logo, does it say "The Dive-O-Matic", or is it the "Divinator"?Anybody remember these? They were all the rage for a while. No idea if they actually did anything aside from promoting neck dive, but they looked sorta cool.
They do not bother me but would sure appreciate one that's totally dead spot free.. I think if you are into tapping, you eould like it to be that way. Modulos and similar graphite necks maybe ? The only one that's bothered me is the 1972 P-bass I had and even attaching plastic clamps on the headstock barely helped. What helped some were very light strings in combo with high action (yes the frets were level ) - I sold that bass.
I do not think you have to go beyond bedroom levels to hear a dead spot . In my case , I do not even have to amplify the bass. We also hear it on upright but they call if wolf tone over there are there are devices made that can help. You just lived with it.
What laws exactly?
I do not think you have to go beyond bedroom levels to hear a dead spot . In my case , I do not even have to amplify the bass. We also hear it on upright but they call if wolf tone over there are there are devices made that can help. You just lived with it.
gM is an intrinsic property of the neck. It’s not adjustable.
I've owned 7 steel 34" scale Warmoth necks and all were significantly better regarding dead spots than any Fender / G&L / Carvin / Washburn / Kubicki / Ibanez I've ever owned or played. The differences are quite noticeable.
I've owned 5 non-reinforced 32" scale Warmoth necks and all have a hint of dead spots. They are not as clean as the steel reinforced 34" necks and not as bad as the Fender ... Ibanez items. Somewhere in between.
I've never had a graphite reinforced Warmoth so I can only guess, but my guess is they not as dead-spot free as the steel necks.
Regarding the weight of steel bars, yes it is a consideration. I've chosen to combat the extra weight by using 2x2 headstocks and ultralight tuners. As a result I have zero neck-heaviness, neck-dive issues. Thus I get the dead spot reduction with no real weight penality.
I suspect many who say they don't have dead spots simply haven't looked using the right methods. If you don't notice them, count your lucky stars! Do NOT go looking for them.
You were told wrong.
Dead spots are when the object’s resonant frequency aligns with a note you intend to play. Every solid object has them. Since Mass is in the denominator a small change can move that note. Away from a fret.
Dead spots are when the object’s resonant frequency aligns with a note you intend to play. Every solid object has them. Since Mass is in the denominator a small change can move that note. Away from a fret.
If the dead note isn’t the same or near the same frequency as a tuned fret within the playing area of the bass the player will say they don’t have a dead spot.
Trombones have dead spots. So do pianos.
I just bought a Warmoth Roasted Maple J neck and don't let the fear of the weight of the standard stiffing rods deter you.
Without hardware my Warmoth neck weighed less that the USA American Standard Fender P neck that I took off of the body.
It was a huge improvement and the neck has no dead spots and it sustains for days.
Without hardware my Warmoth neck weighed less that the USA American Standard Fender P neck that I took off of the body.
It was a huge improvement and the neck has no dead spots and it sustains for days.
D
A bit simplified (I'm no scientist, so please bear with me if everything isn't 100% scientifically correct):
When a note hits the resonant frequency of the instrument, the energy of the vibrating string will be almost instantly be transferred into vibrations of the instrument itself. As a result the string will decay much faster. What we actually hear is a VERY short but loud attack (so short that it can actually be difficult to notice that the attack is louder than normal) and extremely poor sustain. In other words: A dead spot.
The neck is the most flexible part of the instrument (and the part of the instrument that vibrates the most) so that's where most of the string's energy is transferred to the instrument. Stiffening the neck can help with this, but only to a certain point. Stiffening the neck (within reason) will never completely get rid of dead spots. There's also the matter of the dynamics and "feel" of the instrument. If the neck is TOO stiff the dynamic response of the instrument will "feel" wrong, and if materials like steel is used, probably also a bit neck heavy. I guess a theoretical instrument where the neck and body is made of granite, or something like that, could more or less eliminate dead spots, but it wouldn't be a very good instrument.
I certainly have basses where dead spots aren't very noticeable when playing unplugged, or through a small practice amp. But if I play those basses through a bigger amp, with better low end extension, the dead spots become very obvious.
But I've also got basses where the dead spots are VERY noticeable even when playing unplugged.
I think these differences are probably caused by two things:
-The stiffness of neck.
-Whether the resonant frequency of the instrument is at EXACTLY the same frequency as a fretted note with standard tuning or slightly in-between.
Cheap basses with very soft necks are certainly nearly always FAR worse affected. These same instruments also usually suffer from frets where the strings vibrate too MUCH, which causes an uneven response along the neck and problem with fret buzz.
It really boils down to this: Stiffening rods or not, the quality of the wood matters. A LOT!
I found they way @Bruce Johnson constructs necks with carbon fiber tow to be the best method. My 3rd bass built used the epoxy+carbon fiber tow. I've touch that rod once, and is the most enjoyable bass I made.
Attachments
My personal belief is dead spots are caused from:
A: bolt on necks
B: inadequate neck woods
IMHO you don't need reinforcement at all with properly cured, dense neck woods.
Sorry I suppose a dual action truss rod counts as reinforcement. But no other is really needed.
Up to and including 8 string single course instruments.
Then again I could be completely off target, since I have yet to detect any dead spots in my builds.
Good luck,
Dirk
A: bolt on necks
B: inadequate neck woods
IMHO you don't need reinforcement at all with properly cured, dense neck woods.
Sorry I suppose a dual action truss rod counts as reinforcement. But no other is really needed.
Up to and including 8 string single course instruments.
Then again I could be completely off target, since I have yet to detect any dead spots in my builds.
Good luck,
Dirk
If you’re looking for dead spots:
Fender style big headstock, one piece very soft neck with loose truss rod, loose screw neck joint.
If you try to avoid them:
Headless, multi-laminate, quite stiff neck with epoxy bedded truss rod with carbon fiber back strap, machine screw with brass blocks tight neck joint.
The more you have from the later the less chance for dead spots.
Above observations from 40+ basses made, my own experiences. Goes with bass fretboard range (= the range that matters) frequencies.
Fender style big headstock, one piece very soft neck with loose truss rod, loose screw neck joint.
If you try to avoid them:
Headless, multi-laminate, quite stiff neck with epoxy bedded truss rod with carbon fiber back strap, machine screw with brass blocks tight neck joint.
The more you have from the later the less chance for dead spots.
Above observations from 40+ basses made, my own experiences. Goes with bass fretboard range (= the range that matters) frequencies.
I hadn't thought of the headless angle, maybe that's part of why my Steinbegrer has no discernible dead spots? That and an extremely rigid neck made of homogenous material throughout. Wood really isn't the best material to make a neck out of, but it does look and feel nice.
Hi Beej, I got nothin!.
I have only built a handful of basses, 34" and 30" scale length and have never noticed any problem with dead spots. I would hypothesize that dead spots are most likely the result of some combination of construction features and/or mass that end up creating the ability to "soak up" some particular frequency, sort of like a resonance in reverse.
If I were to run into that problem I think I'd first try something like the Fender "Fat Finger" to add significant mass and see if the dead note changed positions or was eliminated
We'll have to wait for Santa to throw in his thoughts.
Thanks! I should have also flagged @rmmottola on this topic, as he's got some great info on his site.Hi Beej, I got nothin!.
I have only built a handful of basses, 34" and 30" scale length and have never noticed any problem with dead spots. I would hypothesize that dead spots are most likely the result of some combination of construction features and/or mass that end up creating the ability to "soak up" some particular frequency, sort of like a resonance in reverse.
If I were to run into that problem I think I'd first try something like the Fender "Fat Finger" to add significant mass and see if the dead note changed positions or was eliminated
We'll have to wait for Santa to throw in his thoughts.
I'm not an engineer but my own reading up on the subject aligns with your comment above about resonance in reverse or 'antiresonance': Antiresonance - Wikipedia
The string is a coupled oscillator and it's experiencing some antiresonance at a frequency associated with those commonly reported dead spot areas (C3ish or around 130Hz). I'd love to sort out what kinds of things might move that dead spot out of the range of the bass so that it's not detectable. I'm guessing that's what I've successfully done with my building techniques and also that there is something about the Fender style (one piece neck, screwed-in neck joint, giant offset headstock) that leads to 130Hz experiencing antiresonance. It would be interesting to understand some of the engineering approaches that could be utilized to somewhat predictably alter the coupled oscillator relationship and eliminate dead spots.
All my basses have Warmoth 5 string necks - the wider of their two widths. The stiffness of a neck goes up dramatically with thickness - a P is stiffer than a J, and my 5 string necks are a step up from that.
Roasted maple is stiffer (and lighter) than regular maple. Both of those things (along with the thickness) help move the resonance frequency of the neck. But we’re not done.
Lighter tuners reduce the mass loading on the neck, which moves the resonance frequency up.
My necks have graphite reinforcement rods. While graphite is lighter than steel, it has about 3x the density of maple. Still, a roasted neck with graphite rods is lighter than an unreinfirced maple neck (I’ve weighed them)
All of this means the dead spot ( what little there is) is not in the fret 4 to 7 range on the G string, it’s up by fret 8 or 9, and it’s very minimal. Most folks wouldn’t notice anything, but I’m really attuned to such things.
All that said, the neck I have with the least noticeable dead spot (I haven’t found one) is a Bronco short scale. The neck is much (5 inches) shorter, I have ultralight tuners on it, so its resonance is even higher than my fancy roasted ones.
Roasted maple is stiffer (and lighter) than regular maple. Both of those things (along with the thickness) help move the resonance frequency of the neck. But we’re not done.
Lighter tuners reduce the mass loading on the neck, which moves the resonance frequency up.
My necks have graphite reinforcement rods. While graphite is lighter than steel, it has about 3x the density of maple. Still, a roasted neck with graphite rods is lighter than an unreinfirced maple neck (I’ve weighed them)
All of this means the dead spot ( what little there is) is not in the fret 4 to 7 range on the G string, it’s up by fret 8 or 9, and it’s very minimal. Most folks wouldn’t notice anything, but I’m really attuned to such things.
All that said, the neck I have with the least noticeable dead spot (I haven’t found one) is a Bronco short scale. The neck is much (5 inches) shorter, I have ultralight tuners on it, so its resonance is even higher than my fancy roasted ones.
All necks, regardless of construction, have resonances - not just one, but multiple frequencies within the range of the bass.Thanks! I should have also flagged @rmmottola on this topic, as he's got some great info on his site.
I'm not an engineer but my own reading up on the subject aligns with your comment above about resonance in reverse or 'antiresonance': Antiresonance - Wikipedia
The string is a coupled oscillator and it's experiencing some antiresonance at a frequency associated with those commonly reported dead spot areas (C3ish or around 130Hz). I'd love to sort out what kinds of things might move that dead spot out of the range of the bass so that it's not detectable. I'm guessing that's what I've successfully done with my building techniques and also that there is something about the Fender style (one piece neck, screwed-in neck joint, giant offset headstock) that leads to 130Hz experiencing antiresonance. It would be interesting to understand some of the engineering approaches that could be utilized to somewhat predictably alter the coupled oscillator relationship and eliminate dead spots.
When a neck vibrates at one of its resonances, different places move more (antinodes) and others move very little (nodes). When the fret that you are playing is at an anti node of the same frequency, the neck (which moves easily at that point at that frequency) takes energy from the string readily, the energy leaves the string quickly, and you have a dead spot.
A lot of talk on here about “bridges coupling energy into the body” and such is complete hogwash. Any time you couple energy from the string into anything else, you are taking energy from the string, which kills sustain. To have good sustain, you need a stuff, massive anchor at both ends of the string, so that energy stays in the string.
Dead spots occur because the neck (which is less stiff and less massive than the body end) is stealing energy from the string at certain point at certain frequencies. I understand the Physics well (I studied this stuff in college). The common wisdom you read on here and other places is a complicated mess of information and misinformation.
