I find myself unlucky that I am unable to find an etymotic dealer in my country (India). I have mailed both Sweetwater and etymotic to see my opportunities to get them to India.
Here's a vague mathematical parametrization I had done quite a while ago using mathematical models of the filters used and the model of balanced armature used:
https://imgur.com/gallery/7AIbRZI
I find it interesting that you find the etymotic easier to drive. With the parameter modelling I could find that they should actually get harder to drive.
To get better bass you'll have to drive the capacitor properly. To get better treble you'll have to drive the inductive part of the ba properly. And there's also an asymptote of impedance maybe around 7khz. The parameter model I took are vague since I reverse interpolated using the impedance chart. Actual point could be anywhere from 3-8khz depending upon how parametrization changes. If there is not enough driving force and slew there either in the source and sink part of the amp I assume that that freqeuncy might get a little offsetted and might come in coarse due to only half of it being driven well.
I expected that if the ba could handle the pressure, the bass performance would be much more solid and capable and from your post it does seem that it does have the capability.
Regardless. This is probably one of the best electrical compensation designs I've ever come across in a long time, other than current feedback amplifier topology. Of course there's also things like srd7 for electrostats and there are stuff that tap speaker output to headphones or systems like raal sr1a, but that's cheating and not an energy efficient design either (they are just brute a lot in and throw away 99%).
If you ever get a chance, please try driving them through a desktop class amp like jds atom with an attenuator inline and let me know how it performs. A high power amp will act as a more stable source and sink.
My apogee groove + hd800 is coming soon. So I'd be able to compare the grooves current feedback amp against my burson fun, which is also arriving soon.
Anyone knows any idea where I can get etymotic stuff in India. I'm not interesred in s,sr, xr, p. The b is the only model I'm interested in.
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