Originally Posted by groovyd
I am curious how changing out the inline resistors that bring the 4s up to 100 ohm with something a little smaller would affect the FR. Has anyone posted FR graphs using different resistor values? Would removing the resistor entirely give the same response as the 4p and reduce the need for an amp? might be cool a slider mini pot in the harness where you can set the resistance.
Check this out:
This is not the ER4's response effect (and don't mind the faulty bass readings), but the principle is the same.
The ER4P has 18 ohms of serial resistance attached to its drivers; the ER4S has 93 ohms of serial resistance.
Here, the effect of no resistor, 20 ohms, and 51 ohms on a Sonion 2354 driver (similar to the ED-29689, but vented) is shown.
BTW, lately I've been using the Dynamic Ear Company Inōr DS-11 (aka Crescendo Hearing Protection DS-11, aka ACS T15) but with a special tip configuration (the stock triple-flanges suck):
Pardon the bad phone camera.
I've then been fitting it as deeply as possible (it can be done because they're so small), up to the 2nd bend, and using a 64 ohm resistor in-line with it.
Of course, 64 ohms is just a ballpark guess. The DS-11 uses a Sonion 2356, which has 26 ohms of DC resistance and 41.5 ohms of impedance @ 1 kHz. Electrical underdamping with 64 ohms seemed reasonable to me, though I suspect that it might need more resistance to sound flatter.
The resulting sound is already very good, however, almost devoid of all spikes, and very neutral in response, like an ER4P but with better bass depth. The only thing that might be lacking is absolute treble extension. There's probably also more distortion (vented drivers have more distortion), but it's not a big issue for me. I haven't had time to compare directly with an ER4 yet, though.
As some of you know, I don't own an ER4 because I find it uncomfortable. These are a bit more comfortable for me, even though they have a wider-mouthed stem.
Rin has measurements for this thing, BTW (but not with these tips, of course), just not posted yet. I don't know when they'll be ready.