Yes, and unfortunately it wasn't an oxidation problem. I'm pretty sure it's the internal assembly being loose.

So unfortunately, my IER-M9's left side connector is extremely finicky. Keeps breaking connection. And then, to my surprise, I found out the warranty was only for 1 year! Jeez, talk about stingy! And worse, just the inspection fee for the repair from the authorised repairer is $110 AUD! Y'all...

I'm not saying the ER2s are a bad IEM (far from it, actually) - it's just that if your emphasis is sub-bass, look elsewhere or EQ it. The ER2XE has it, it's just hidden relative to the mids. If you want deep sounding earphones, you tend to try and go for dark-sounding ones or U-shaped IEMs.

Sure, but their mid-range overshadows the bass. It's there, but you need to tease it out with EQ to knock off the mid-range. -------------------- If you're looking at sub-bass and don't mind shelling out the pennies, 64 Audio really hits that itch without cheating by straying into the upper...

Look at figure 41a at the link: that corresponds to your experience.

Yes: it's easier for low frequencies to mask high frequencies, than it is the other way around. Here's something you can read if you're interested: they provide an explanation why. Hearing: 11.3.1 A masking experiment - OpenLearn - Open University - SD329_1 Applying this knowledge, this means...

High output impedance (unless we're talking about tubes) means poor design. There is literally never a good reason to have it in the headphone world, unless you're trying to divide power down using a resistor divider circuits (think speaker amps with a headphone output). Speakers? You tend to...

Pretty easy to in specific cases. IEMs are a fun case for electronics. If your amp's output impedance is high, your bass response goes funky. Also, a lot of computers output a lot of noise and hiss, especially when the power draw skyrockets (e.g. CPU does something intensive). High powered amps...

Mine are flush, no recess: wish mine had the recess.

Definitely was a 0.78mm cable, at least that's what Massdrop claims.

That's interesting, because on my A12T's the connection is ridiculously stiff and solid with the stock cable. On the other hand, an aftermarket cable was so loose it falls out if I breath on it.

Don't know why you're being combative, because I never accused you of saying it was the cause. Lower impedance does not draw more power from the amp, it draws a bigger proportion of current than voltage. Very important difference there. Audible hiss of 1 mV into an impedance 4 times lower would...

Somewhat correct, but your explanation is incorrect. Noise floor is something that's measured in voltage, not current. Impedance does not govern power, it governs the balance between current and voltage. If you double the impedance, yes your theoretical power output drops by a factor of two...

Not really, at least for Poweramp. Poweramp has its own audio engine that allows for a much more precise EQ. Also allows access to direct volume control, which makes the EQ changes go more extreme with less distortion. But, if everything's turned off, is it better? Nope. EXCEPT when dealing with...

You say that, but some critics of A/B testing is that it's too quick, so if anything, they want an extended period of time to test.