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What determines the width of an accuracy node?

seymour fish said:
JRS, You have lost me, as when I strike a pipe, then cut it in half and strike it again, it rings at higher frequency. Seymour
The frequency remains the same with the same piece a different length. However, the sound wave changes. Thus, the different sound you hear. Though each different length of pipe on a wind chime produces a different sound, the frequency remains the same. If you added one of Mikes tuners to the chime, you could change the frequency on each pipe.
 
JRS said:
seymour fish said:
JRS, You have lost me, as when I strike a pipe, then cut it in half and strike it again, it rings at higher frequency. Seymour
The frequency remains the same with the same piece a different length. However, the sound wave changes. Thus, the different sound you hear. Though each different length of pipe on a wind chime produces a different sound, the frequency remains the same. If you added one of Mikes tuners to the chime, you could change the frequency on each pipe.
Interesting...That's not how I thought it worked, at all. Wouldn't simply having a different sound infer a different frequency?
 
JRS said:
seymour fish said:
JRS, You have lost me, as when I strike a pipe, then cut it in half and strike it again, it rings at higher frequency. Seymour
The frequency remains the same with the same piece a different length. However, the sound wave changes. Thus, the different sound you hear.

I also have a degree in Music. When it comes to what we hear, any overtones pretty much dominate how we interpret the sound. Chimes and bells are particularly vexing, at least to my ears - what's left of them.
 
brians356 said:
JRS said:
seymour fish said:
JRS, You have lost me, as when I strike a pipe, then cut it in half and strike it again, it rings at higher frequency. Seymour
The frequency remains the same with the same piece a different length. However, the sound wave changes. Thus, the different sound you hear.

I also have a degree in Music. When it comes to what we hear, any overtones pretty much dominate how we interpret the sound. Chimes and bells are particularly vexing, at least to my ears.
May I infer that it might have to do with how our eardrum vibrates in colder(more dense) or warmer air, or is it simply how sound travels through the air?
 
gunsandgunsmithing said:
brians356 said:
JRS said:
seymour fish said:
JRS, You have lost me, as when I strike a pipe, then cut it in half and strike it again, it rings at higher frequency. Seymour
The frequency remains the same with the same piece a different length. However, the sound wave changes. Thus, the different sound you hear.

I also have a degree in Music. When it comes to what we hear, any overtones pretty much dominate how we interpret the sound. Chimes and bells are particularly vexing, at least to my ears.
May I infer that it might have to do with how our eardrum vibrates in colder(more dense) or warmer air, or is it simply how sound travels through the air?

The sound (pitch and tone) of a chime, for example, doesn't change perceptibly with temperature. But two objects having the same fundamental pitch (frequency) may sound radically different due to their complex and rich harmonics (overtones).

I suppose in the same way, two barrels with the same fundamental construction, shape, and mass distribution could make very different patterns on the target.
 
I believe this is why Mike's tuners work. By way of adjusting the tuner, you can move the vibrations to different locations [opposite if you will] at the same frequency. At some point, in the optimal location, that tuner will cancel out the vibration.
 
I have no data or have seen no evidence either way on my point of view, but I believe when you are talking tens of thousands of psi with a bullet running down the bore all the tuning fork analogies go out the window. A rifle barrel is unique. I can not imagine a barrel only having one frequency of vibration per mode. Like I said, its my belief. If there is any data otherwise I would love to see it.
 
JRS said:
I believe this is why Mike's tuners work. By way of adjusting the tuner, you can move the vibrations to different locations [opposite if you will] at the same frequency.
FWIW, I believe that's why all properly made tuners work. All tuners do this. Mine just has a better ability to manage those vibrations, with less total muzzle displacement that solid mass tuners, due to the particle dampening aspect of mine. If what preliminary tests show holds true, it lowers the frequency more, with less amplitude....meaning it slows the barrel as well as reducing how far it moves, at the same time.
 
zfastmalibu said:
I have no data or have seen no evidence either way on my point of view, but I believe when you are talking tens of thousands of psi with a bullet running down the bore all the tuning fork analogies go out the window. A rifle barrel is unique. I can not imagine a barrel only having one frequency of vibration per mode. Like I said, its my belief. If there is any data otherwise I would love to see it.
I believe testing on my tuners will only cover what's happening at the muzzle., not end to end. Perhaps I can find an answer for you during testing. I'll make a note and if it's feasible, we'll know.
 
zfastmalibu said:
I have no data or have seen no evidence either way on my point of view, but I believe when you are talking tens of thousands of psi with a bullet running down the bore all the tuning fork analogies go out the window. A rifle barrel is unique. I can not imagine a barrel only having one frequency of vibration per mode. Like I said, its my belief. If there is any data otherwise I would love to see it.

I certainly don't disagree. And I hope I didn't imply otherwise in my simplistic musings about what might generally determine the width of an accuracy node. But it remains highly debatable just how much affect the subsidiary frequencies have on the width of the accuracy node, compared to the fundamental. It's about as knowable as how much warmer (or colder) the planet will be 100 years from now - if anyone cares.
 
The air column certain shortens as the bullet moves down it, but the tube doesn't. I would suspect it stays the same...but I don't know.
 
zfastmalibu said:
I have no data or have seen no evidence either way on my point of view, but I believe when you are talking tens of thousands of psi with a bullet running down the bore all the tuning fork analogies go out the window. A rifle barrel is unique. I can not imagine a barrel only having one frequency of vibration per mode. Like I said, its my belief. If there is any data otherwise I would love to see it.
Lets say the frequency of that barrel is 60 HZ. That is 60,000 cycles per second. It makes no difference whether the barrel is 36" long, or 26" long, 1.450, or 1.250 in diameter. The frequency remains constant.
 
JRS said:
zfastmalibu said:
I have no data or have seen no evidence either way on my point of view, but I believe when you are talking tens of thousands of psi with a bullet running down the bore all the tuning fork analogies go out the window. A rifle barrel is unique. I can not imagine a barrel only having one frequency of vibration per mode. Like I said, its my belief. If there is any data otherwise I would love to see it.
Lets say the frequency of that barrel is 60 HZ. That is 60,000 cycles per second. It makes no difference whether the barrel is 36" long, or 26" long, 1.450, or 1.250 in diameter. The frequency remains constant.
I am not saying you are wrong, as I have no data. Do you have any data to back up your side? If mass is the only way to change the frequency then simply changing bullets weights would have this effect, no? To clarify, I have only been talking about the vibration modes while the bullet is in the barrel, as I don't care what the barrel does after the bullet leaves. I do agree with you about the frequency being constant, once the bullet leaves the bore, but not while it is in it.
 
just to throw another dog into the ring-what would happen when a rifle was fired in a vacuum[if this is possible] would the harmonics etc remain .
the reason i ask is i watched an intresting programme on tv about testing in a huge vaccum chamber -as the chamber had near to zero gravity.amazing
 
Mike, while the bullet is moving down the bore the barrel has a constantly moving mass. Same as screwing a tuner in or out. IMO this will cause the frequency to be altered. The barrel in not a constant mass like the analogies. All of the analogies apply to a barrel after the bullet has left the bore.
 
CatShooter said:
4xforfun said:
"If you are comparing 26" barrels, the heavier one (e.i. the fatter one) that is "normally made, will ring at a lower frequency."



Another nit pic...wouldn't the wave lengths of a shorter/stiffer tube be shorter and closer together? Wouldn't that be considered a HIGHER frequency. That is how it is in the music world, not sure about the engineering world.

You missed the operative phrase... "If you are comparing 26" barrels, " The comparison is barrels that are the same 26" length - there is no shorter one.

Sorry...I mis spoke, I meant heavyer STIFFER tube ( of the same length) ring at a HIGER frequency. the peaks of the frequency waves are closer together...thus a HIGHER frequency.

Or am I wrong? :o
 
4xforfun said:
CatShooter said:
4xforfun said:
"If you are comparing 26" barrels, the heavier one (e.i. the fatter one) that is "normally made, will ring at a lower frequency."



Another nit pic...wouldn't the wave lengths of a shorter/stiffer tube be shorter and closer together? Wouldn't that be considered a HIGHER frequency. That is how it is in the music world, not sure about the engineering world.

You missed the operative phrase... "If you are comparing 26" barrels, " The comparison is barrels that are the same 26" length - there is no shorter one.

Sorry...I mis spoke, I meant heavyer STIFFER tube ( of the same length) ring at a HIGER frequency. the peaks of the frequency waves are closer together...thus a HIGHER frequency.

Or am I wrong? :o


Sounds right to me.
 
garyw said:
just to throw another dog into the ring-what would happen when a rifle was fired in a vacuum[if this is possible] would the harmonics etc remain .
the reason i ask is i watched an intresting programme on tv about testing in a huge vaccum chamber -as the chamber had near to zero gravity.amazing
Pretty much everything would change if fired in a vacuum. Fortunately, that's not feasible and doesn't matter, unless it helps make your point about something.
 
If reducing vibration is your only concern, shoot a lighter bullet at higher velocities. Otherwise, there is but one option. Install a tuner, and relocate the vibration.
 
zfastmalibu said:
Mike, while the bullet is moving down the bore the barrel has a constantly moving mass. Same as screwing a tuner in or out. IMO this will cause the frequency to be altered. The barrel in not a constant mass like the analogies. All of the analogies apply to a barrel after the bullet has left the bore.
Off the top of my head, I can't see how the mass of the barrel would change, regardless of where in the barrel the bullet is or how that alone, would change it's natural frequency...other than the barrel effectively becoming a solid rod, rather than a tube where the bullet is at any given time.. I do see your point though, and it's probably a good one, but as long as it moves down the bore the same way every time(or very close), I don't know how it would affect shot to shot tune. At least I think I follow your logic.--Mike
 

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