"The YH-100 mod falls somewhere between the LCD-2 and LCD-X in signature. It is tuned warm, has plenty of detail and a good slam. The LCD2 is smoother and presents with a darker tone, while the LCD X is brighter and airier sounding. The KH100 mod is a bit narrower in stage and does not have the same verticality as the LCDs, likely due to the smaller driver size, but for being closed backs they extend beyond the ears nicely.

With the original pair I tested, I had an HD580 to compare directly, and they were very similar in a lot of ways but had more low end. This new version reminds me of a better HD600 or even 650 given that they are on the warmer side of things. I owned a HD600 multiple times and love how natural it sounds, but I would pick up the KH100 mod over it at this point."

"I think for the price too its very solid and competes well with headphones in the $500-$1000 range."

"Comfort: excellent sense of comfort, the Sony chassis is very well designed, and the addition of your woven headband cover, plus leather pads, which are soft and supple, add to the comfort. I can wear these for an extended period of time without ever feeling any discomfort. Definitely better than the supra-aural pads of the stock YH-100. 

Isolation: being a closed back monitor, isolation is quite good. It's able to cut away a good amount of the noise of my air purifier in my bedroom. 

Sound impressions: wow, this is like a whole nother beast compared to the stock YH-100. Comparing back and forth, while the stock sound is perfectly fine for my ears, compared to the KH-100, the stock sounds quite dull in comparison. The KH to my ears has a more extended bass response, reaching down lower than stock, which I attribute to your tuning, plus the closed cups and circum-aural pads. [...]

Going into the midrange, to my ears, I perceive it as well-balanced, with just the right amount of emphasis, I'm not noticing any erroneous peaks or nulls. […]

Treble is the area that surprised me the most. It's crazy to think that these are still YH drivers, what you managed to do with them here is impressive. This is where the difference is greatest compared to stock. Treble is nice and detailed, but never overbearing or sibilant. Extension is very good. […]

Instrument separation and detail have of course noticeably gone up with your mod. What sounded as more congested in the YH, comes alive in the KH. Again, it's hard to believe that these are the same drivers. The KH really transformed these into another animal."