There are direct equivalents in mechanical and electrical systems. For simple harmonic motion, you have mass, compliance and damping on the one hand and inductance, capacitance and resistance on the other, as direct equivalents. Don't just take my word for it:
https://en.wikipedia.org/wiki/Mechanical–electrical_analogies#:~:text=Mechanical–electrical%20analogies%20are%20used,between%20mechanical%20and%20electrical%20parameters.
https://en.wikipedia.org/wiki/Mechanical–electrical_analogies#:~:text=Mechanical–electrical%20analogies%20are%20used,between%20mechanical%20and%20electrical%20parameters.
Yes, in engineering and science it is often helpful to make technical analogies, such as analyzing harmonic motion as an electrical circuit, or creating virtual concepts such as acoustical impedance or mechanical impedance. These technical analogies rely on some simplifying assumptions, but as long as the assumptions are valid, these techniques allow us to solve problems.
In much the same way, the assumption of rigid body motion is central to fields of kinematics and dynamics. Cone motion at frequencies below the first mode resonance are best analyzed with the assumption of rigid body motion.
j.
In much the same way, the assumption of rigid body motion is central to fields of kinematics and dynamics. Cone motion at frequencies below the first mode resonance are best analyzed with the assumption of rigid body motion.
j.
Here's an equivalent circuit for a speaker (and this IS simplified, because it's covering only the simple harmonic behaviour around main resonance, fs).
https://audiojudgement.com/speaker-equivalent-circuit/
https://audiojudgement.com/speaker-equivalent-circuit/
These are all equivalence circuit that are used not because they represent the behaviour but because we need the mathematics and models to represent it to solve the mathematical part analytically (ie without a powerful computer) so you can figure out the box size etc. In the context of resonance analysis and other frequency behaviour it works well because it is a sine analysis. But it does not apply to all behaviour. The behaviour is different in the sense if you have an amplifier, you can just say go from 0V to 5V and go back to 0V immediately (Sawtooth wave). This can be easily done by an amplifier. But not necessarily a speaker cone, because the speaker cone has momentum. It can't stop immediately and turn around, it will overshoot before turning around.
So the model works well when you are trying to simulate frequency response before cone break up when fed with a sinewave. However that model cannot be used to predict for example how the output waveform will look like if you fed it a square wave. You would need to model it differently. Even in electronic modelling there are different modelling aspects. For example in SPICE. You could model how a circuit will behave in a frequency sweep or how a signal transient analysis will look like. They both used very different method of computation and you would need to specify right at the beginning of the software, what type of modelling that you use.
So the model works well when you are trying to simulate frequency response before cone break up when fed with a sinewave. However that model cannot be used to predict for example how the output waveform will look like if you fed it a square wave. You would need to model it differently. Even in electronic modelling there are different modelling aspects. For example in SPICE. You could model how a circuit will behave in a frequency sweep or how a signal transient analysis will look like. They both used very different method of computation and you would need to specify right at the beginning of the software, what type of modelling that you use.
We are not going to redo the works of acousticians and loudspeaker legends like Neville Thiele or Richard Small, are we?
I might add that Eargle’s Loudspeaker Handbook b-force referred to is on sale big time now at Springer. E-book Edition 1997, but not a lot has changed. Anyone serious about loudspeakers should have a copy.
I might add that Eargle’s Loudspeaker Handbook b-force referred to is on sale big time now at Springer. E-book Edition 1997, but not a lot has changed. Anyone serious about loudspeakers should have a copy.
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Pretty fundamental is an understatement.
It's the main core of control theory.
Not one space rocket, or any other controlled system would work without it.
These models work great, it just depends how extensive you make them. Even most BEM/FEM techniques have their fundamentals in these analog equivalents.
It's kind of shocking that some people seem to be so strongly opinionated, yet lack any knowledge and experience in basic and fundamental physics.
I seriously doubt if some can even name any proper literature.
At this point it's not just redoing Thiele's and Small's work, but redoing what physics is based on.
Totally silly and absurd.
Unfortunately it was to be expected.
Well, you can model a speaker cone's lumped mass - that's what the linked web-page describes (mass being modelled as capacitance).
But as I've been saying, the cone is more complex than that - it's a transmission surface, and that would be much more difficult to model. But that's not because there's incompatibility between electrical and mechanical analogies and models, it's because of shear complexity. Having said that, you could no doubt quite easily construct an approximation of a speaker cone's behaviour as a transmission line which is improperly terminated.
No, it's because we are leaving the piston region. Anything outside this piston behavior won't (necessarily) follow these equivalent models.
The same could happen when multiple sub-systems start to interact with each other.
Those FEM/BEM techniques have been around for decades btw.
Including FineCone and COMSOL.
As the Wikipedia page mentions. This is an analogy. It is not a true representation of all mechanical behaviour. That model is good for predicting matters like frequency response, resonant frequency etc. But it can't be used to model other properties, like for example cone break up, cone flexing, transient response of irregular waveforms etc.
BTW. I will like to highlight that there is 2 discussions going on here. My point is not about speaker cone and suspension termination. I am not too familiar with that.
My aim is purely at the people who says that looking at the frequency response at 1W and THD and immediately they would say that this is all you need and if your speakers has a flat frequency response and the THD is low it will be a fantastic sounding speaker. The so called Measurements are all that matters camp and there are those who just go by ear. I am somewhere in between, there are some acoustical properties of speakers that can't be described in the basic tests that we perform, frequency response, THD etc. They cannot be used to measure properties such as sonic detail etc.
I agree with the idea that pixel peeping is not very useful, but saying that there are some magical voodoo things going on that can't be measured, is kinda strange.
I think that has more to do with lack of understanding what's going on. Nofi
Besides, measuring things and data are nothing more than useful tools.
In the end it's a question of how likely you're able to predict certain things, even how things are gonna sound.
When properly used:
I have never came across speakers that measured great but "sounded" bad.
I have come across some speakers that sounded fine but didn't measure so well.
I have come across far more speakers that sounded bad and it was very clear from measurements and data why.
So in the end, why would I spent money and time into things that have a lower change of success? That just doesn't make any sense to me.
That's like randomly throwing ingredients together in the hope it will taste well?
Even if those ingredients are of high quality, the wrong combination will still taste awful. Any serious chef will also have extensive knowledge about what works and what not.
I think that has more to do with lack of understanding what's going on. Nofi
Besides, measuring things and data are nothing more than useful tools.
In the end it's a question of how likely you're able to predict certain things, even how things are gonna sound.
When properly used:
I have never came across speakers that measured great but "sounded" bad.
I have come across some speakers that sounded fine but didn't measure so well.
I have come across far more speakers that sounded bad and it was very clear from measurements and data why.
So in the end, why would I spent money and time into things that have a lower change of success? That just doesn't make any sense to me.
That's like randomly throwing ingredients together in the hope it will taste well?
Even if those ingredients are of high quality, the wrong combination will still taste awful. Any serious chef will also have extensive knowledge about what works and what not.
At least with round speakers, the 3d shape can probably be reduced to a 1d equivalent for simulation, as we're mostly dealing with a transmission line with a voice coil (of a certain bulk) at one end, a 'line' of paper or some other material and a piece of rubber at the other end.
The real world subtleties would probably involve things like spiral-wound coils where the forces aren't perfectly perpendicular to the magnet gap. You can simulate that for fun, but it's one of those things where time may be better spent developing a jig that produces better coils, or steam-rolls the wire or something like that.
Things probably get a bit more fun with oval cones because of the assymmetry. I'd guess that even the air load is assymmetric (with round cones too). In one polarity of motion the air tends to 'spill' and slide off the cone, while in the other direction it gets scooped, and the cone is put under tension.
The real world subtleties would probably involve things like spiral-wound coils where the forces aren't perfectly perpendicular to the magnet gap. You can simulate that for fun, but it's one of those things where time may be better spent developing a jig that produces better coils, or steam-rolls the wire or something like that.
Things probably get a bit more fun with oval cones because of the assymmetry. I'd guess that even the air load is assymmetric (with round cones too). In one polarity of motion the air tends to 'spill' and slide off the cone, while in the other direction it gets scooped, and the cone is put under tension.
Horses for courses as people say. It depends on the application. I also use a very light membrane fullranger as midbass driver in a horn to reveal low level details, but there are more ways to accomplish that.
Hold your horses, there we go again. Light membranes are no guarantee for ‘low level details’. Don’t start about hysteresis, 
even at low levels cones move, if it only were for the amp noise.
@abstract ‘we‘ can FEM non-round cones almost as easily as round cones (the FEM itself is just the same, only the modeling is a bit more work). So simplification to 1D models is not only not necessary, it’s unwanted.
even at low levels cones move, if it only were for the amp noise.@abstract ‘we‘ can FEM non-round cones almost as easily as round cones (the FEM itself is just the same, only the modeling is a bit more work). So simplification to 1D models is not only not necessary, it’s unwanted.
Agreed, only if coupled to a powerful magnet and decent design of the surrounding parts.