[Vamp898]

After quite some time of frustrating researching, i give up and hope that maybe someone here can explain it to me.

Speaker diaphragm, why am i asking.

The MDR-Z7M2 does have a aluminum Coated LCP diaphragm.
The MDR-Z1R does have the same diaphragm, but replaced the dome with an magnesium alloy which enabled the headphones to reach 120KHz instead of 100KHz (and changed the overall characteristic too, but the 120KHz is the thing that made me think).

Only the dome is made of magnesium allow, the rest of the diaphragm (the ring?) is still made of aluminum coated LCP.

What exactly is the job of the dome? Is the ring responsible for the lower frequencies and the dome for the higher? But the whole diaphragm is moving when its moving, to my knowledge there is no separate control of the dome and the ring.

I don't get it. Why not make the whole diaphragm out of magnesium alloy?

Maybe these questions sound stupid but neither wikipedia nor any other side i found could explain what exactly the job of the dome is and why it makes sense to use a different material for it.

 

[71 dB]

It is an engineering challenge to design a diaphragm that works well over 10 octaves, from 20 Hz to 20.000 Hz. Voice coil is attached to the edges of the dome. That's were we hav the most accurate movements controlled by the voice coil. The diaphragm and the dome are not infinitely rigid. They will resonate at certain frequencies. Also, the diaphragm won't move as much in the edge area as it is moving at the dome edge. High frequencies are mostly radiated from the dome which is very rigid due to its shape. Lower frequencies are radiated all over the diaphragm. Making the whole diaphragm very rigid may cause serious resonances at audible frequencies. Making the diaphragm too soft/damped may cause insufficient high frequency response. It is about finding a compromise between these problems typically having the resonances at extremely high frequencies far from audible range. This explains use of different materials in different parts of the diaphragm. Manufacturing costs may also have an effect on how materials are used, sometimes even (snake oil) marketing.

 

[Vamp898]

Thank you very much for your explanation! That kinda explains why i haven't found that much information about it as the questions cause is due to an misunderstanding.

 

[MayaTlab]

Maybe that post from Oratory1990 could provide some info : https://www.reddit.com/r/headphones/comments/bacd37/duck_duck_goose/ekaxsri/

 

[Blackwoof]

What exactly is the job of the dome? Is the ring responsible for the lower frequencies and the dome for the higher? But the whole diaphragm is moving when its moving, to my knowledge there is no separate control of the dome and the ring.

I don't get it. Why not make the whole diaphragm out of magnesium alloy?

Bass is done on the outer area of the diaphragm and mids/treble done in the centre. If It too stiff it can't produce bass properly BA drivers get away with full metal diaphragm because they use a rod being pulled by a armature while DD are just cones.