I just got back from my friend's sound lab and thought I'd post some quick impressions. Here's a rundown of the equipment we used:
Mackie 6 headphone mixer
Laptop running WinAmp
Violectric V200 amp
Violectric V800 DAC
Logitech Squeezebox Touch
And the headphones present:
HiFiMAN HE-500 X2 (his and mine)
Sennheiser HD600
Denon AH-D7000
Denon AH-D2000
Round one (level match all headphones):
WinAmp from the laptop to the V800 via optical then to the mixer via unbalanced plugs. We played pink noise through each headphone one at a time and measured it with a professional studio mic (I don't remember the model) to level match all headphones to 75dB on the mixer.
Then we started the music (the tracks I previously mentioned here where I detected recessed treble detail and/or bloated mids on the HE-500).
We first compared his HE-500's to mine. Neither of us could detect a difference. We both agreed that the HE-500 has something going on in the midrange. Whether it's the bass bleeding up or something else, the HE-500's sounded a little tubby and thick on some recordings - like looking outside through a window that's got a layer of haze on it. My friend was actually surprised by how good the D7000's sounded. They sounded clearer with obviously beefed up bass that was not obtrusive or bleeding into the midrange. Brighter than the HE-500, there was also more detail retrieval, although some of the sounds I couldn't hear on the 500's, he could clearly hear. In part, I attribute this to my hearing loss and tinnitus. He was even more surprised by the D2000's. For the $200 I paid for them, they come very close to the performance of the D7000. The notable difference between them is a little looser bass control and slightly hotter (but not sibilant) treble in the 2000. Finally, the HD 600. It has been a while since I sold my pair so I was looking forward to hearing them again. They were as I remembered - the most neutral of the group with nice treble detail, natural mids, and good bass, though the bass lacks punch and weight compared to the Denons and HiFiMAN. We agreed that vocals sounded the most natural of all the headphones on the Sennheiser's.
We spent the most time here listening to a variety of music and swapping headphones. No blind testing, but the differences were large enough to easily distinguish between all of them.
Round two (compare mixer output to V200):
We moved his HE-500's from the mixing board to the V200 (now fed from the V800 via analog RCA cables. Again, we level matched them with pink noise to the other headphones. This round was relatively short because neither of us could detect a difference between the two HE-500's.
Round three (final):
We disconnected the mixer and plugged in my system. My Logitech Squeezebox Touch was the source, simultaneously outputting via optical to the V800 and V200 and via analog RCA cables to my Carver Receiver. We loaded the pink noise file onto my thumb drive and played it from the Squeezebox to level match the two amps (V200 and Carver).
Then we switched to music and focused exclusively on the D7000, switching back and forth between the V200 and my Carver. My friend said that he heard a little more clarity from the Violectric system, which he attributed to the V800's superiority over the Logitch's built-in DAC. He was however very surprised by how small the difference was. I personally couldn't tell the difference between the two, but took him at his word because he is a pro audio scientist and also does not suffer from hearing loss. He commented that the difference only appeared to him above about 4kHz and it was only on the decay following certain sounds. From 4kHz and below, he said he couldn't hear any difference.
My conclusions by the end of the day were clear:
1. I don't think the HE-500 is the headphone for me for the reasons I mentioned previously. What I was hearing from them on my system was repeated in the lab using high resolution equipment and I am satisfied that it's not my imagination. I much prefer the "clarity" of the D7000's and for those tracks where the bass overwhelms, my receiver has tone controls to knock it back down to size.
2. My Carver Receiver is one heck of a good amp that goes toe-to-toe with highly respected dedicated solid state headphone amps. The V200 is now the fourth amp (Schiit Asgard, Peachtree Nova, and Objective2) that I have directly compared it to with no difference detected. With the benefit of powering my speakers, serving as a preamp for all my sources, and it's inclusion of tone controls to tweak the sound to my liking, it would be foolish of me to replace or supplement it.
3. The V800 is now the third outboard DAC (Peachtree Nova and Cambridge Audio DacMagic are the other two) that I have compared to the Squeezebox's built-in DAC with no difference detected. Clearly, the biggest difference in sound is from one model headphone to another. From there, tubes are probably the next way to color your sound in a significant way (albeit in a trial and error, hit or miss manner). Upgrading from one well designed DAC and/or solid state amp to the next is basically a waste of time AFAIC. The differences claimed by manufacturers, sellers, and some enthusiasts are at the very least, highly overstated in my humble opinion.
4. The Sennheiser HD 600 is still a terrific headphone. You can spend a lot more money and still not necessarily get better sound.
Tune in next week for my opinion of powering the HiFiMAN headphones from 130WPC speaker taps!
