Audax Sd value

Svante · 28th April 2004, 12:04 PM

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 · 28th April 2004, 12:11 PM

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 · 28th April 2004, 12:19 PM

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 · 28th April 2004, 01:49 PM

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 · 28th April 2004, 02:58 PM

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 · 28th April 2004, 03:09 PM

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 · 28th April 2004, 10:46 PM

Looks like 78cm^2 to me.

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

28th April 2004, 12:04 PM	#1
Svante diyAudio Member Join Date: Feb 2004 Location: Stockholm	Audax Sd value 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? __________________ Simulate loudspeakers: Basta! Simulate the baffle step: The Edge

28th April 2004, 01:49 PM	#4
Ron E diyAudio Member Join Date: Jun 2002 Location: USA, MN	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. __________________ Our species needs, and deserves, a citizenry with minds wide awake and a basic understanding of how the world works. --Carl Sagan Science is a way of thinking much more than it is a body of knowledge. --Carl Sagan

28th April 2004, 02:58 PM	#5
5th element diyAudio Member Join Date: Oct 2002 Location: England	Sd for the HM130Z0 is 80cm2, Z12 is 81, google! u find it out.! Oh the phase plugs are fixed like Seas excel. Matt __________________ What the hell are you screamin' for? Every five minutes there's a bomb or somethin'! I'm leavin! bzzzz! Droggon Attack!

28th April 2004, 10:46 PM	#7
Ron E diyAudio Member Join Date: Jun 2002 Location: USA, MN	Looks like 78cm^2 to me. Sd=pi(Do^2-Di^2)/4 __________________ Our species needs, and deserves, a citizenry with minds wide awake and a basic understanding of how the world works. --Carl Sagan* Science is a way of thinking much more than it is a body of knowledge. --Carl Sagan

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28th April 2004, 12:11 PM	#2
richie00boy Did it Himself diyAudio Member Join Date: Nov 2003 Location: Gloucestershire, England, UK	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.

28th April 2004, 12:19 PM	#3
tiroth diyAudio Member Join Date: Dec 2001 Location: Pittsburgh, PA, USA	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.

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