[hoshiyomi]

I've been curious about this for while...
What are the highest impedance IEMs on the market at the moment?
 
There is plenty of voltage at the source to burn so sensitivity is not an issue, just want them to be high impedance so they can be easy on the output stage.
 
So far I could only find Hifiman Re-262 which is 150 ohms impedance, and maybe Re-0 and 64 ohms... but I'd prefer something in the 300-600 ohms range if such cans exist.
The other option might be to find a pair of sensitive single transducer IEMs with linear impedance across the audio band then heavily pad it down with serial resistance, but I'd prefer to not go that route.
 
Thanks for your input.

 

[Golila3]

I don't know about too many IEMs, but the highest I've known of is the heir Audio tzar350. 350ohm

 

[hoshiyomi]

To answer the question myself, looks like the new Ety Kids are 300 ohms and somewhat ridiculously low sensitivity, might actually be done through having a large resistor in series with the dynamic transducer...
 

 

[soundstige]

I believe it's done with having a very inefficient (stiff/heavy) material for the dynamic driver. I have a pair and there's no resistor in the cable, and it's not like Etymotic to put them in the earpieces themselves.
 
Quote:

To answer the question myself, looks like the new Ety Kids are 300 ohms and somewhat ridiculously low sensitivity, might actually be done through having a large resistor in series with the dynamic transducer...
 

 

[hoshiyomi]

Quote:

I believe it's done with having a very inefficient (stiff/heavy) material for the dynamic driver. I have a pair and there's no resistor in the cable, and it's not like Etymotic to put them in the earpieces themselves.
 

Well there is only one way to find out, I am likely getting a pair and will eventually open them up once they die of a natural death, albeit this might be years down the road. lol
 
The impulse response plots I found looks really clean so either acoustic dampers are doing wonders, or that these really use 300 ohm transducers?  It's just that high impedance dynamic transducers tend to exhibit a bit of rise in impedance by 20khz due to coil inductance, but these look fairly linear throughout the audio range.