[Russin]

Hey, Head-Fi - been reading reviews here for as long as I can remember in a casual capacity, but never had much in the way of my own gear to really start sharpening my listening. Just recently decided to take the plunge into something of my own, firmly in the low-mid range.
 
I'm doing an awful lot of reading and just trying to learn as much as I can, but after a whirlwind local listening tour, I picked out some cans (a pair of Hifiman 400is). They're in the mail, which is exciting.
 
In the pocket amp department, I couldn't find anywhere to side-by-side test, so I had to go on reviews and descriptions alone. After much brain wracking, I ordered a JDS Labs C5D, which showed up last night.
 
I plopped it down on my desk next to my Focusrite 2i2, and decided to give some comparison listening on the IEMs I have at hand (ATH-IM70)  to see if I could really hear a difference (which I expected to).
 
One of the very first things I noticed was that the C5D seemed almost muted or muddy in some way - kind of like someone took a chunk out of the upper mids. I jumped back and forth between the devices on a number of tracks and genres, and while the C5D bass sounded full and detailed, it almost seemed like the 2i2 had some "magic" in the upper ranges that surprised me. Shouldn't the JDS Labs be the hands-down "winner?"
 
I was so nervy about it that I downloaded FuzzMeasure and tried to mesaure the Frequency Response charts, but I have no idea what I'm doing and just ended up producing  near-identical-looking curves for the two devices. The FocusRite had better impulse response! I think I'll leave this part to the professionals for now.
 
Could it just be that I'm not used to hearing what actual neutral sound is like? Did I misrate the potential capabilities of the 2i2? Or was is the C5D that I was over-expecting from? I've heard the C5D is dark, but precise - will it be too much with the already dark 400is?
 
Thanks for assuaging a nervous newbie. I still have so much to learn...

 

[ProtegeManiac]

 
I plopped it down on my desk next to my Focusrite 2i2, and decided to give some comparison listening on the IEMs I have at hand (ATH-IM70)  to see if I could really hear a difference (which I expected to).
 
One of the very first things I noticed was that the C5D seemed almost muted or muddy in some way - kind of like someone took a chunk out of the upper mids. I jumped back and forth between the devices on a number of tracks and genres, and while the C5D bass sounded full and detailed, it almost seemed like the 2i2 had some "magic" in the upper ranges that surprised me. Shouldn't the JDS Labs be the hands-down "winner?"
 
I was so nervy about it that I downloaded FuzzMeasure and tried to mesaure the Frequency Response charts, but I have no idea what I'm doing and just ended up producing  near-identical-looking curves for the two devices. The FocusRite had better impulse response! I think I'll leave this part to the professionals for now.
 
Could it just be that I'm not used to hearing what actual neutral sound is like? Did I misrate the potential capabilities of the 2i2? Or was is the C5D that I was over-expecting from? I've heard the C5D is dark, but precise - will it be too much with the already dark 400is?

 
The high output impedance of the 2i2 could be EQing the bass, in this case, reducing it. Your C5D just isn't altering the response of the IEM but the 2i2 might be.

 

[Russin]

   
The high output impedance of the 2i2 could be EQing the bass, in this case, reducing it. Your C5D just isn't altering the response of the IEM but the 2i2 might be.

 
Interesting. So to see if I'm understanding this:
 
The IEMs are about 16 OHMs impedance. Output impedance of the C5D is <1, so has no problem driving a consistent signal through low-impedance headphones which are in the 10-15x impedance range.
 
The Scarlett 2i2 has ~10 OHMs output impedance, which is way more than 10x less than the IEMs, so it can't be expected to be able to produce a consistent frequency response at that low of an input impedance?
 
Is what I said just total nonsense? Is there any good reading to understand how high output impedance could result in changes to EQ? I haven't been able to find much online.
 
Thank you!

 

[ProtegeManiac]

 
The IEMs are about 16 OHMs impedance. Output impedance of the C5D is <1, so has no problem driving a consistent signal through low-impedance headphones which are in the 10-15x impedance range.

 

Yes. And no you don't need 10-15x the output impedance. 8x is what is generally followed as mathematically it's what generally wouldn't affect damping factor, but I've tried even less than that and sometimes there's no problem. Of course that can be because the damping factor was high enough to begin with, but again just to skip all the number crunching, 8x is what people generally follow.
 

 
The Scarlett 2i2 has ~10 OHMs output impedance, which is way more than 10x less than the IEMs, so it can't be expected to be able to produce a consistent frequency response at that low of an input impedance?
 
Is what I said just total nonsense? Is there any good reading to understand how high output impedance could result in changes to EQ? I haven't been able to find much online.

 
 
https://en.wikipedia.org/wiki/Damping_factor
http://www.amplifier.cd/Tutorial/Innenwiderstand/output_resistance.htm