Audax Sd value

[Svante]

Does anyone know where to find Sd values for Audax speakers?

In particular I am interested in HM130Z12.

Also, does anyone know if the "phase plug" moves with the cone or if it is fixed?

 

[richie00boy]

Can you find a Pd value? This is just the diameter, so Sd (which is area) can be found by pi * [(Pd/2) * (Pd/2)]. Remember to convert the Pd units into what your target Sd units should be first.

 

[tiroth]

I think a good Sd figure can't be geometrically calculated since it depends in part in the flexion of the surround and the edges of the cone.

The phase plug is fixed.

 

[Ron E]

If the use for the spec is noncritical, I'd just say it has a 10cm diameter and subtract the 2.5cm plug area from that. For most modeling purposes, this is good enough. So much so that if you want better, it would be best to just buy one and measure it yourself.

Geometrically, it makes sense to use half the surround when measuring Sd. The cone should move as a piston until several octaves above resonance, so talk of flexion at low frequencies is nonsense.

 

[5th element]

Sd for the HM130Z0 is 80cm2, Z12 is 81, google! u find it out.!

Oh the phase plugs are fixed like Seas excel.

Matt

 

[Svante]

Thank you all. I arrived at 84 cm2 from measuring on the front view (counting pixels) on the image below. So 80 or 81 seems good considering that the plug does not move.

Isn't it amazing that Audax doesn't include a Sd number in the data sheet, or at least a diameter figure?

 

[Ron E]

Looks like 78cm^2 to me.

Sd=pi*(Do^2-Di^2)/4