Modelling driver movement

[Holmz]

I am trying to model the cone movement as a finction of the voltage applied to the motor over time.

I see the BL curve, and I could model the current from the voltage and the impedance curve. And generate a motor force.
And I could then subtract from the KMS of the suspension.
And then later the mass of the cone and voice coil, would directly affect the acceleration… assuming that that even matters… which it probablt does more for a woofer than a tweeter.

But there is also the mass of the air coupled to the cone, and the rarefied air on one side pulling the cone, and the compressed air on the other fighting the cone force.

And then if the voice coil is unpowered, it will gradually move towards zero as the KMS pulls it back… and maybe get there more quickly if the impedance across the terminals is high.

Is there a particular website or book that describes the physics that I would need to model all this to first order?

 

[McFly]

Maybe here? Not sure but give it a skim

https://www.acculution.com/blog

He was a guest on erins audio corner a while back, theres a video on his channel. Also Lars Risbo is quite an active poster over in the multi way forum at diyaudio.

 

[NTK]

You can take a look at these 2 COMSOL tutorials.

https://www.comsol.com/model/download/1040051/models.aco.lumped_loudspeaker_driver.pdf

https://www.comsol.com/model/download/1040351/models.mbd.lumped_loudspeaker_driver_mechanical.pdf

Parent web pages:

Lumped Loudspeaker Driver

Use this model or demo application file (and its accompanying instructions) as a starting point for your own simulation work.

www.comsol.com

Lumped Loudspeaker Driver Using a Lumped Mechanical System

Use this model or demo application file (and its accompanying instructions) as a starting point for your own simulation work.

www.comsol.com

 

[Juhazi]

A commercial product https://www.loudsoft.com/finecone/

 

[Holmz]

Maybe here? Not sure but give it a skim

https://www.acculution.com/blog

He was a guest on erins audio corner a while back, theres a video on his channel. Also Lars Risbo is quite an active poster over in the multi way forum at diyaudio.

I’ll peruse @René - Acculution.com site…

 

[René - Acculution.com]

You can do a lumped circuit model of this in the time domain.

 

[NTK]

Here is an example of the time domain simulation of a lumped circuit model as mentioned by @René - Acculution.com.

https://www.researchgate.net/publication/311536265_Fully_Coupled_Time-Domain_Simulations_of_Loudspeaker_Transducer_Motors

The speaker driver model is separated into 2 parts. The first part is the "lumped parameter" (LP) model for the time domain simulation (see equation 3). The second part is the FEA analyses to model the nonlinear behaviors of Bl(x), Kms(x) ( =1/Cms(x) ), and Le(x) as functions of the cone displacement x. The results of the second part is fed into the time domain simulation of the first part to simulate the actual displacement (and acceleration) of the cone.

Alternatively, you can get the Bl(x), Kms(x), and Le(x) from measurements such as those done by @hardisj

Purifi Audio PTT6.5M-08-NFA-01A 6.5 Inch MidWoofer Review

Purifi Audio PTT6.5M-08-NFA-01A 6.5 Inch MidWoofer Review

www.erinsaudiocorner.com