I'm used to doing everything (production, mixing, mastering) on my Sennheiser HD600 & a Subpac. I bought an Etymotic ER4XR because I read a lot of good things about it & thought it might be easier to use when traveling. I figured it would be a good IEM to play around with before jumping on a Shure SE846. From the moment I plugged it into the Subpac, I got feedback right way. It wasn't volume dependent, just a noticeable constant hiss which I also got with another pair of earphones when I tested. When I plug the HD600 back in...zero hiss. The biggest problem was the sound. It's heavy in the mid-high to high region. So much so that when I bring the volume to a comfortable listening level, the bass is hardly heard or felt on the Subpac. I had to crank the Sub-pac dial up to 80% where the HD600 is normally around 40-50%.

So do these ER4XR need break in period and do I need some type of software/plugin in order to tune the IEMs properly? I was expecting plug n play as I do not use any additional software with my HD600/Subpac.

 

i have zero experience with a subpac, but what you describe sounds like an impedance issue.

 

Because they are deep in the ear, you have to watch out for your hearing protection.
In other words, they are a little quieter otherwise your hearing would be damaged.

ER4XR - Technical specs

Frequency response: 20Hz - 16KHz
Both channels in the range 100Hz - 10kHz tuned to 1dB accuracy
Isolation: 35-42dB
Impedance: 45Ω
Sensitivity: 98dB SPL @ 1kHz
Max SPL: 122dB
Manufactured and fine-tuned in the USA

HD 600 - Technical specs

• Dynamic
• Open
• Circumaural
• Impedance: 300 Ohm
• Sound pressure level: 97 dB
• Frequency range: 12 - 39,000 Hz
• Cabling from both headphones
• 3 m cable with 3.5 mm jack connection
• Weight without cable: 253 g
• Weight with cable: 309 g
• Including 6.3 mm adapter

 

Last edited: May 21, 2021

Not my experience using them onstage, but hey!
I wonder how much the IEMs mentioned in the OP cost?

edit: less than half the price of what I know of; I just checked.
What amp is driving these IEMs?

An amp?

 

Last edited: May 21, 2021

@BEAT16 I thought the same thing initially. But with the IEM I had to turn down the volume compared to the HD600. The ER4XR were noticeably louder than the cans. And like I said, especially in the upper regions.

@Smooth Grooves I got them for $129 shipped from Adorama.

So I was testing them on my home studio not a laptop. Basically the Subpac control box is connected to the phone plug of a TC Electronics Konnect 6. The HD600/IEM is connected to the phone plug of the Subpac control box. I didn't think I needed an amp since the headphones ran fine without one for the past few yrs.

 

No surprise, less ohm, higher max SPL.