Falbo Intension Bridge

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Re: Falbo Intension Bridge

Post by seeaxe » Thu Oct 27, 2016 8:29 pm

DarwinStrings wrote:
seeaxe wrote:
So to my good mates on this forum, in my humble opinion is not very polite (and probably also incorrect) to say that someone else doesn't know how a guitar works just because they cannot, or perhaps choose not, to explain what they are doing in terms we understand or would like them to use. Especially when we all acknowledge we don't know it all either! So in aussie parlance, I think that's a bit on the nose, just my opinion of course.
Well I reckon you'd be talking to me there Richard. I was just being frank (pun intended) not impolite and what I said was that this was my impression or opinion I have formed from reading what Frank had had to say in some of his videos and on this forum and that I may be incorrect. The post I posted before this one is an attempt to show Frank what I mean and I do not intent offence I just want to be able to speak my mind.

I think it is a bit on the nose for you to try to pull me into line Richard, that is Bob and Martins job, they have done it before and no doubt if I get out of line again they will do it again.
Noted, Jim, as you say, you are welcome to your opinion as I am to mine. I don't need to be a moderator to express it. For the record I wasn't just talking about you. There were several posts that were, in my opinion, a bit less than friendly in tone and I think that's a shame.

Whatever. If I have ruffled any feathers I am happy to apologise also.

All the best

Richard
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Re: Falbo Intension Bridge

Post by hepikohetaniwha » Thu Oct 27, 2016 10:40 pm

I have another probably quite dumb question. When I wire my lounge speakers wrong, they're 'out of phase', but this refers to the polarity of the wires. It does mean that as one speaker moves forward, the other moves back (assuming perfect amp output linearity etc). However, phase linearity of the signal as heard depends not just upon the speakers' wiring, but also upon the frequency component plus the position of the listener. You may be sitting at a node for one frequency but an antinode for another frequency. Even when you wire your speakers right, at most places in your lounge, some frequencies will be out of phase just because there are two sound sources at different distances from you. So my question is, if a guitar design has eliminated phase nonlinearities, does that mean it should only be mixed in mono?

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Re: Falbo Intension Bridge

Post by DarwinStrings » Sun Oct 30, 2016 3:31 pm

Don't have an answer for you Hep (can't find a name for you but did google hepikohetaniwha just in case it was your name).

Richard I checked your location and as you are a Kiwi (or maybe just live there) you should have realised that if I had meant any offence to Frank I would have began my sentences with "No offence but".

This thread has been a positive one for me as it has got me off my rear to learn a little more about terms that I am not familiar with and the term "comb filtering" had my interest especially. So the term is used in the recording of instruments when you mix two signals and one of those signals has been delayed (say from two mics at different distances to the source). So how to relate that to a guitar in a acoustic situation.
frankfalbo wrote:The dipole vibration puts out-of-phase information into the top, resulting in comb filtering.
So we know from the physics that the long and cross dipole have two antinodes that are 180 degrees out of phase with each other (this should also apply to the monopole cause the antinode in the middle of the board is out of phase with the rim or any part on the other side of the monopole node). So how does this cause comb filtering? It seems there needs to be a delay involved and the only way I can see that occurring and relate it to Frank's quote above is that there is some delay between the pressure waves coming off the two antinodes, in that they are a different distance from your ear causing a delay which is interesting because it would seem to relate better the the monopole and the cross dipole rather(for the player not the listener) than the long dipole (which Franks design suppresses).
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Re: Falbo Intension Bridge

Post by frankfalbo » Tue Nov 01, 2016 6:27 am

DarwinStrings wrote:So we know from the physics that the long and cross dipole have two antinodes that are 180 degrees out of phase with each other (this should also apply to the monopole cause the antinode in the middle of the board is out of phase with the rim or any part on the other side of the monopole node). So how does this cause comb filtering? It seems there needs to be a delay involved and the only way I can see that occurring and relate it to Frank's quote above is that there is some delay between the pressure waves coming off the two antinodes, in that they are a different distance from your ear causing a delay which is interesting because it would seem to relate better the the monopole and the cross dipole rather(for the player not the listener) than the long dipole (which Franks design suppresses).
Just the presence of two out of phase zones creates comb filtering. It doesn't technically require "time". It is true, the time constant is responsible for some of the phase smearing in the convoluted sound that hits a microphone or our ears. But two sound sources can be 180 degrees out of phase and occur in the same time constant. That's the hard definition of 180 degrees out.

Electrically, if two identical signals (one out of phase) were combined in mono the result is silence. Acoustically, whether a guitar top or a speaker cabinet, the result is comb filtering. This can change with location. Like if you have a left/right speaker set out of phase, when you physically move yourself closer to the Left speaker, it begins to take over, and the sound of the right speaker is distant. When you're sitting dead center, the sound is thin and the ear-brain doesn't know what to make of the location. It may sound like there are speakers behind you or directly to the side right?

So now, just imagine two out of phase locations on the spruce, with a null in the center between them. They are pushing sound into the air that is convoluted. In this case the comb filtering I'm referring to occurs in the air in front of the guitar. It also affects the reflections inside the box, but we all pretty much understand those are highly convoluted anyway. There is a comb filtering that occurs within the spruce top of course. I mean, that it would occur in a vacuum and is not related to sound waves penetrating the air. Like how a 12th fret harmonic combs/cancels the fundamental in a string, the spruce top is now the most significant part of a feedback loop between the string and the guitar. This is what I refer to when I say you can play my guitar out of tune, dropped 1/4 step, with dissonant chords, dissonant chords AND out of tune...and all 6 strings ring out more uniformly and with less beating. The more the harmonic extensions get caught in these "closed loops" (on a torqued top) the more they argue with one another when a chord is sustaining. They return vibrations to the string that are in argument with it. This changes the decay/sustain duration and is part of the "warbling" or beating sound as well.

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Re: Falbo Intension Bridge

Post by jeffhigh » Tue Nov 01, 2016 9:17 am

frankfalbo wrote:
DarwinStrings wrote:So we know from the physics that the long and cross dipole have two antinodes that are 180 degrees out of phase with each other (this should also apply to the monopole cause the antinode in the middle of the board is out of phase with the rim or any part on the other side of the monopole node). So how does this cause comb filtering? It seems there needs to be a delay involved and the only way I can see that occurring and relate it to Frank's quote above is that there is some delay between the pressure waves coming off the two antinodes, in that they are a different distance from your ear causing a delay which is interesting because it would seem to relate better the the monopole and the cross dipole rather(for the player not the listener) than the long dipole (which Franks design suppresses).
Just the presence of two out of phase zones creates comb filtering. It doesn't technically require "time". It is true, the time constant is responsible for some of the phase smearing in the convoluted sound that hits a microphone or our ears. But two sound sources can be 180 degrees out of phase and occur in the same time constant. That's the hard definition of 180 degrees out.

Electrically, if two identical signals (one out of phase) were combined in mono the result is silence. Acoustically, whether a guitar top or a speaker cabinet, the result is comb filtering. This can change with location. Like if you have a left/right speaker set out of phase, when you physically move yourself closer to the Left speaker, it begins to take over, and the sound of the right speaker is distant. When you're sitting dead center, the sound is thin and the ear-brain doesn't know what to make of the location. It may sound like there are speakers behind you or directly to the side right?

So now, just imagine two out of phase locations on the spruce, with a null in the center between them. They are pushing sound into the air that is convoluted. In this case the comb filtering I'm referring to occurs in the air in front of the guitar. It also affects the reflections inside the box, but we all pretty much understand those are highly convoluted anyway. There is a comb filtering that occurs within the spruce top of course. I mean, that it would occur in a vacuum and is not related to sound waves penetrating the air. Like how a 12th fret harmonic combs/cancels the fundamental in a string, the spruce top is now the most significant part of a feedback loop between the string and the guitar. This is what I refer to when I say you can play my guitar out of tune, dropped 1/4 step, with dissonant chords, dissonant chords AND out of tune...and all 6 strings ring out more uniformly and with less beating. The more the harmonic extensions get caught in these "closed loops" (on a torqued top) the more they argue with one another when a chord is sustaining. They return vibrations to the string that are in argument with it. This changes the decay/sustain duration and is part of the "warbling" or beating sound as well.
From Wikipedia, the free encyclopedia
In signal processing, a comb filter adds a delayed version of a signal to itself, causing constructive and destructive interference. The frequency response of a comb filter consists of a series of regularly spaced notches, giving the appearance of a comb.

I think Jim is right, there needs to be a delay to the signal not just a constant out of Phase. The comb filter effect is the result of this delay which results in some frequencies cancelling while others are reinforced. You don't get this with just a phase shift.

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Re: Falbo Intension Bridge

Post by kiwigeo » Tue Nov 01, 2016 9:56 am

Correct me if I'm wrong but mixing phase shifted signals is the basis of the phase shift effect pedal while the flanger pedal works by mixing two time delayed signals.
Martin

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Re: Falbo Intension Bridge

Post by DarwinStrings » Tue Nov 01, 2016 11:50 am

From this quote " Like how a 12th fret harmonic combs/cancels the fundamental in a string" I get that you are referring to comb filtering as phase cancelling so that clears something up Frank.

I have pointed it out but I will go again just in case I am not communicating my point well.

From what you have said here Frank you describe your set up as having the ability to suppress the long dipole (sometimes you just refer to the "dipole" and you have referred to the "dipole delta") yet you make no mention of the phase cancelling in the other modes. which includes the monopole and with the right bracing and mass distribution it is possible to change the node position of the monopole to make that mode more or less phase cancelling (area inside the node compared to area outside the node). This also includes the cross dipole which from the chladni patterns would generally be more phase cancelling than the long dipole.

Suppressing the long dipole can be achived on a conventional bridge guitar, you can do it with a cross brace and with a lattice you can suppress all those lower order modes that are higher frequency than the monopole.

What I get from what has been said is that Frank has achieved an amazing result and it seems that result is being attributed to the suppression of the long dipole or perhaps from one statement that the long dipole has been manipulated to get less phase cancellation.

Be careful messing around with those Efex pedals Martin as you may end up putting the acoustic away and playing long lead solos
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Re: Falbo Intension Bridge

Post by frankfalbo » Tue Nov 01, 2016 1:04 pm

jeffhigh wrote:I think Jim is right, there needs to be a delay to the signal not just a constant out of Phase. The comb filter effect is the result of this delay which results in some frequencies cancelling while others are reinforced. You don't get this with just a phase shift.
Well yeah, Wikipedia is referring to (mono) signal processing. I'm talking about multiple sound sources combining in the air, and/or into a mic. In the acoustic space, distance IS time.

For example if you have two speakers in the same cabinet, whether they're in OR out of phase with one another, there will be varying degrees of comb filtering as you drag a mic across from one speaker to the other.

What I refer to with dragging a mic across one of my guitars vs. a traditional guitar is that the mic sound goes from bassy to thin and bassy again. Some of that is the condition of the sound coming off the top, but some of it is the cancelling/combing sound from a neighboring area also entering the mic.

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Re: Falbo Intension Bridge

Post by jeffhigh » Tue Nov 01, 2016 1:13 pm

Distance may equal delay
But you are so opposed to the long dipole because it has two out of phase areas,
Phase opposition represents a shift to one signal of half the wavelength which is not a constant time but dependant on the frequency, as opposed to the fixed delay found in comb filtering.

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Re: Falbo Intension Bridge

Post by DarwinStrings » Tue Nov 01, 2016 3:11 pm

Another way to suppress the long dipole is to shove a "bridge doctor" in. With a bridge doctor you can also remove the lower bout bracing (not that I can see why you would). Interestingly people I have met are convinced that putting a bridge doctor in their guitar "improved tone".
frankfalbo wrote:
For example if you have two speakers in the same cabinet, whether they're in OR out of phase with one another, there will be varying degrees of comb filtering as you drag a mic across from one speaker to the other.
frankfalbo wrote:What I refer to with dragging a mic across one of my guitars vs. a traditional guitar is that the mic sound goes from bassy to thin and bassy again. Some of that is the condition of the sound coming off the top, but some of it is the cancelling/combing sound from a neighboring area also entering the mic.
This will be the same condition for both guitars as they both have multiple modes that are phase cancelling. "Neighbouring area" what like the sides or back, perhaps then neck or do you mean reverb from a wall or obstacle. It would seem that all of those condition will be the same for your design as from the trad.
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Re: Falbo Intension Bridge

Post by johnparchem » Wed Nov 02, 2016 1:11 am

This is a very interesting discussion. Jim your bridge doctor comments and your discussion of other ways to suppress the long dipole (like lattice bracing) is helping me get an understanding of the mechanics involved and helps me take the design of the intension bridge from magic to the more traditional set of tradeoffs made in acoustic guitar designs. If I understand your point in a somewhat simplistic way the bridge doctor shunts the rotational force on the bridge to the end block suppressing the long dipole. Moving the string termination point closer to the end block would also shunt some of that rotational force to the end of the guitar. If I understand this at all then it seems like the design of the Intension bridge would allow Frank to dial in the amount of rotational force to shunt toward the end of the guitar by choosing the distance from the saddle and the height of the termination point from the top. From other comments it seems like the Intension bridge removes the lower bout braces to allow for the added mass of the this bridge system.

Suppressing some of the vibrational modes would change the tone and the apparent loudness (to a human listener) of the sound. Jim's comment on the lattice bracing brought to mind discussions of the sound of a Smallman classical guitar played by Williams vs a Torres\Hauser style classical played by Bream. Some like the clean sound of the Smallman other the fat tone of a more traditional classical.

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Re: Falbo Intension Bridge

Post by frankfalbo » Wed Nov 02, 2016 1:30 am

Well the most significant difference between the Intension design and things like the bridge doctor is that there are no touch-off points that transfer energy elsewhere. All the string tension is placed right there at the bridge area to drive the top from the center outward.

And point of clarification the transverse braces behind the bridge aren't omitted to make room for the bridge mechanism. The mechanism is small. They're omitted because they're not required.

I can rethink everything about the bracing pattern, but I have left the X brace because of how it drives the top, not because I need the X to converge in front of the bridge to handle the torque. I've successfully integrated the Intension bridge with a ladder brace pattern as well. It's just a different sound. Someday I may market that into some models.

I've also retrofitted it onto a Taylor Dread. Not for commercial purposes, a friend asked if I would, as his guitar was very special to him but had a top crack and lift. The end result? It still sounded "like a taylor" but transferred almost all of the salient features I'm ascribing. The sustain, the sensitivity, the improvement in phase alignment...and I left their transverse braces.

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Re: Falbo Intension Bridge

Post by johnparchem » Wed Nov 02, 2016 3:17 am

frankfalbo wrote:Well the most significant difference between the Intension design and things like the bridge doctor is that there are no touch-off points that transfer energy elsewhere. All the string tension is placed right there at the bridge area to drive the top from the center outward.
I am missing something. In the bridge doctor there is a rod to transfer the force that wants to rotate the bridge to the end block. In your design there is still the top that transfers some of that force to the end block supported rims. In my mind the closer one is to the rims the more of the force that would have rotated the bridge is trying to bend the rims. Being a bit slow I always need a mental model before I understand the math. If I take termination of the strings right to rims with a tail piece as an extreme I can imaging that a termination of the strings straight to the top 1 mm from the rims would not be that different Even though I have no "touch off point" It is still the rims that want to bend not the bridge. As I move that termination point closer to the traditional SS bridge location the torque from strings and the lever of saddle will increasingly start rotating the bridge. I understand that you have a component with some angles and height off the inside of the top. But in my limit ability to understand if I added up all of the force vectors it can still be reduced to an equivalent termination point between the bridge and rims.

I think what you are doing is clever and I do not dismiss the attributes that you claim. Mainly I am just trying to understand as an intellectual effort.

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Re: Falbo Intension Bridge

Post by DarwinStrings » Wed Nov 02, 2016 3:31 pm

Just to be clear John, it is not my claim that Frank's design suppresses the long dipole that is Frank's claim. I am not sure if his design does in fact suppress the long dipole as I have seen no evidence of it. I am assuming that what Frank said is true for the discussion.

Frank says two things, in the quote below he talks about reducing or cancelling the long dipole. Then in the quote below that he talks about his bridge design as making the two signals of the "dipole delta" more phase aligned. So I have to take from that that he has not "cancelled" the long dipole cause if you manage to cancel it then there won't be no phase to align.
frankfalbo wrote:So it's Trent's first post that is correct, in that my long dipole is reduced/cancelled in favor of the monopole.
frankfalbo wrote:
For example (on a torqued bridge) I could place two contact transducers on the top, one near the sound hole, the other behind the bridge. (The dipole delta) Both will have a measurable frequency response. But more importantly, if I overlay them against one another, they won't be phase aligned. So there's a phase smearing across the time constant, compounded by the smearing of the box reflections.

With the torque neutralized, the two signals are more phase aligned. That means they push audio into the air and the box with greater linearity.
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Re: Falbo Intension Bridge

Post by DarwinStrings » Wed Nov 02, 2016 6:08 pm

I forgot to mention while I was on the last post the last sentence in that second quote, it says.....

"That means they push audio into the air and the box with greater linearity."

Why the need to mention anything about that mode (long dipole) pushing audio into the box unless you are referring to the air associated with that mode but as you have "reduced/cancelled" that mode I doubt you will get much of a air mode from it.
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Re: Falbo Intension Bridge

Post by hepikohetaniwha » Thu Nov 03, 2016 2:49 pm

Maybe it amounts to the same thing... like if I take a wheel off my bi-cycle it's now a uni-cycle... if you phase align the two poles of a dipole then you have a monopole...?

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Re: Falbo Intension Bridge

Post by DarwinStrings » Wed Nov 16, 2016 1:18 pm

You don't get the last word sorry Hep
frankfalbo wrote:
DarwinStrings wrote:Frank,Trent asks "Do you have any frequency response curves of your design that you can share? Also do you have any deflection measurement of the monopole mobility?"

You answer in part with this "I cannot give deflection numbers because first, they are meaningless without a benchmark"

Trent is referring to Trevor Gore's "monopole mobility" calculation. Trevor has published benchmarks for this measurement.
Ok understood. I was taking the simpler language from kiwigeo just referring to "lower bout deflection". So it's Trent's first post that is correct, in that my long dipole is reduced/cancelled in favor of the monopole. With this in mind, this is where I start to talk about phase linearity and the comb filtering present within an acoustic top driven by torque. Amplitude, frequency density, and projection are now (in my experience) no longer directly tied to pure excursion data. In simpler terms, there are some speakers that have a longer excursion delta, that still are not the "loudest" nor have the longest throw in a group of their peers. When comparing two tops that are torque-driven, Trevor's numbers are what I mean by a benchmark. They are relevant because each is torque-driven.
Some of you guys will already know and understand this stuff, so more for those of you who don't.

I don't expect that Frank has read Trevor and Gerards books so I guess he would't understand what is involved in Trevor's "Monopole specific mobility" measurement but I would like to point out that it is not a simple measurement of "excursion" but a measurement of sensitivity to vibration.

The deflection measurement is taken to work out a value for the stiffness of the completed top, the load used to deflect the top is divided by the deflection to give a value for the stiffness. Also a value for the mass of the top is calculated from the uncoupled (to the air) monopole frequency.

Once you have these values you can then work out a figure for monopole specific mobility.

Nothing in these calculations has anything to do with "tops that are torque-driven" there is no figure for "torque" in the spring/mass calculation and as Franks design is still a plate driven by a set of strings so this measurement would apply to his design equally as it would apply to the traditional bridge design and the benchmarks that have been published would be relevant for Frank's guitar. This measurement would show if Franks guitars are more responsive than those "good" factory guitars or if they are more responsive than my guitars.
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Re: Falbo Intension Bridge

Post by simonm » Wed Nov 30, 2016 8:58 am

lamanoditrento wrote:I found his patent application for the design, but not sure if I am any the wiser
US20150243262A1.pdf
I had a look at this just now for the first time. The way I would summarize it, is a "new improved internal tailpiece-like string connector" except of course it is not attached to the tail but to the top and inside rather than outside. Compared to other through the top designs the main feature is the additional string connector which is placed further back from the string holes. I wonder how easy it is to string up. A rear port would solve that of course. The devil is in the detail of the construction to get the weight distribution right.

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