- Dec 9, 2016
Lol you have gone so far!Indeed, the smaller unit is much less prominent in response.
It is definitely not an electret - either some magnetostat or some flat suspended membrane.
Here are the inner parts:
Two symmetric coils inside the ring magnets (8 Ohm each connected in parallel, so the total impedance is 4 Ohm).
In between is the rigid metal membrane that is at the bottom of the image. Interestingly, it is magnetic but not magnetized.
I am not sure whether this design is similar to other MSTs or some unique construction of KZ/CCA.
Because of the very rigid membrane, the amount of sound it can produce is fairly limited, and the range is limited as well: some output is from 1.2 kHz to 12.5 kHz, while the sound can be heard reasonably in the range of ca. 3.5 kHz to 7 kHz then decaying to oblivion by 12.5 kHz.
P. S. It was really hard to disassemble, please do kids-friendly designs next time, KZ/CCA
Yeah I think due to the much higher efficiency of DD, for lower driver count IEMs, the DD is always full frequency and all BAs, EST and MST, electret etc. are for the purpose of adding detail or note weight.
No idea how an electret unit should look like but you mentioned ring magnets being 8 ohms each, are they just copper coils since you shouldn't be able to measure the resistance of a magnet I assume? And the membrane maybe polarized so it can feel the magnetic field?
You can use nail polish remover or resin softener to remove the resin between the drivers and the shell cavity to extract thr drivers, and then use a hairdryer to apply excessive heat to the drivers and they may just come apart.
So have you tried the NRA without the electret/MST driver?