A Symmetrical Transducer Topology

[mwmkravchenko]

Both were pushed a fair distance to give you an idea of the force required. Hope it helps.

As I mentioned before I don't take a lot of effort to do these calculations as our real world iterations tend to make a proper salad out of them.

I'll be away this weekend at a retreat in the Wilds of Canada but I'll bring my torture top with me. If you need another simulation let me know. I managed to get an invite to Doug Schneider's Canadian Audio Cognoscenti retreat. As I've joked for the past 35 years, I've fooled them so far

 

[smowry]

Hi @mwmkravchenko,

Thank you, but what did you use for material properties?

Modulus:

Density:

Poisson's Ratio:

 

[mwmkravchenko]

Hi @mwmkravchenko,

Thank you, but what did you use for material properties?

Modulus:

Density:

Poisson's Ratio:

I was away this past weekend Steve. We made up a table back in 2017 of the different spider materials. I'll see if I can find the information that you need. Obviously I have it, It's in the program in order to make the calculations! But the question is where do I have it!

 

[mwmkravchenko]

Hi @mwmkravchenko,

Thank you, but what did you use for material properties?

Modulus:

Density:

Poisson's Ratio:

See what happens when it has been 8 years since we launched this thing! I forget where I put what. So the genius idea was to have a materials table. It's normally buried far right.

 

[smowry]

@mwmkravchenko

Kindly let me confirm the isotropic linear elastic material properties.

Type 10 (Pro Surround)
Young's Modulus: 50 KSI
Poisson's Ratio: 0.35

This appears to be a cotton/polyester blend. In 2006 I used 25,000 PSI for Modulus and 0.3 Poisson's Ratio for cotton/poly. Back then I would understate modulus so as not to mask any geometric instabilities. So this seems to check out okay.

https://pearl-hifi.com/06_Lit_Archive/14_Books_Tech_Papers/Mowry_Steve/Another_Spider_Article.pdf

Type 4 (Spider)
Young's Modulus: 500 KSI
Poisson's Ratio: 0.35

The Modulus seems overstated. 500 KSI is typical of a high performance diaphragm material like high performance polymer and seems too stiff for suspension components.

Mechanical Properties-Modulus of Elasticity equal 500 ksi polymer product list

List of polymers which Mechanical Properties-Modulus of Elasticity equal 500 ksi

www.lookpolymers.com

FINEsuspension has default spider material properties for typical fabric of 100 KSI and for Conex of 150 KSI and 0.33 Poisson's Ratio for both.

Anyway, I will use your material properties for the surround simulation so that we can compare results.

Type 10 (Pro Surround)
Young's Modulus: 50 KSI
Poisson's Ratio: 0.35

However, for spider simulations, I will use the FINEsuspension default material properties and most likely 100 KSI for modulus.

 

[mwmkravchenko]

@mwmkravchenko

Kindly let me confirm the isotropic linear elastic material properties.

Type 10 (Pro Surround)
Young's Modulus: 25 KSI
Poisson's Ratio: 0.35

This appears to be a cotton/polyester blend. In 2006 I used 25,000 PSI for Modulus and 0.3 Poisson's Ratio for cotton/poly. So this seems to check out okay.

https://pearl-hifi.com/06_Lit_Archive/14_Books_Tech_Papers/Mowry_Steve/Another_Spider_Article.pdf

Type 4 (Spider)
Young's Modulus: 500 KSI
Poisson's Ratio: 0.35

The Modulus seems overstated. 500 KSI is typical of a high performance diaphragm material like carbon fiber and seems way too stiff for suspension components.

https://www.lookpolymers.com/findproperty.php?pid=2&sx_id=114&value=500

FINEsuspension has default spider material properties for typical fabric of 100 KSI and for Conex of 150 KSI and 0.33 Poisson's Ratio for both.

Anyway, I will use your material properties for the surround simulation so that we can compare results.

Type 10 (Pro Surround)
Young's Modulus: 25 KSI
Poisson's Ratio: 0.35

However, for spider simulations, I will use the FINEsuspension default material properties and most likely the Conex properties.

I think that we can both enter in what ever material properties that we wish Steve. I use this mostly for making sure that I have the excursion that I need. I use Hakken for spiders and they know what they are doing much better than I do. I do not mind leaving the design of these things to the guys that do it all day every day. If I have dual mirrored or whatever then we get a little more involved. What ever we input as to the material properties has a lot less to do with the end result. We don't know the phenolic setting properties, the heat at press, or the compression of the linen or what ever fabric we choose. I learned a long time ago to turn off the OCD on some things. I chase flux, generally to good results. Motor shapes and cooling ideas. Other than that I work with those who I trust.