Mmd?

[jaya000]

Some say Mmd means diaphram weight ,
Some say Mmd means recone kit assembly/full cone assembly weight
Some say Mmd means recone kit assembly/full cone assembly weight less half weight of surround.

Which is proper?

[kelticwizard]

Mmd = diaphragm weight, including voice coil.

Both the original cone and replacement cone should weigh about the same, so there shouldn't be a problem there.

As for the surround-I doubt it weighs very much in comparison to the diaphragm and voice coil, so I wouldn't worry about it.

[jaya000]

As for the surround-I doubt it weighs very much in comparison to the diaphragm and voice coil, so I wouldn't worry about it.

The cone comes with surround. So u mean to say that we must include the full surround weight.

The recone assembly means cone, voice coil, spider dust cap & glue.

[David McBean]

Originally posted by jaya000
Some say Mmd means diaphram weight ,
Some say Mmd means recone kit assembly/full cone assembly weight
Some say Mmd means recone kit assembly/full cone assembly weight less half weight of surround.

Which is proper?

Hi jaya000,

Mmd is the total mass of those components of a drive unit that actually move when a signal voltage is applied to the voice coil. Because the spider and surround are fixed at their outer edges, the general rule is to include half their masses only.

Therefore Mmd = mass of (voice coil + 1/2 spider + cone + dust cap + 1/2 surround + glue)

Hope this helps.

Kind regards,

David

[jaya000]

Thank u very much David McBean!
U hv clarified it in the very nice way.