Originally Posted by bigshot
Many headpones have a bump up in the upper mids/low high end. They do this to make them sound louder and "in your face" with electronic music. But if you listen to acoustic guitar, jazz, chamber or orchestral music, a colored headphone will never do, because acoustic instruments have a baseline response in reality that we all recognize. Electronic instruments can be adjusted to sound any way the performer wants, so that baseline doesn't exist. But even with electronic instruments, a carefully calibrated response will give you exactly the same sound the performer intended, because studio monitors are always calibrated flat. The Oppos don't have any bump or dip. They have a perfectly balanced response. You could easily add the "in your face" bump to them with a 3 or 4dB boost around 3kHz and they would sound exactly like what you are used to with colored headphones. You could also create the "fat bass" sound of some cans by doing the same around 80Hz. Specific sound signatures are just deviations from flat. If a set of headphones is capable of reproducing a flat response, it can be EQed to sound like any sound signature you want.
Contrary to common thought among audiophiles, headphones don't have soundstage the way speakers have soundstage. Two transducers shooting directly into your ear canal can only create a straight line of sound directly through the middle of the head. It can't create a 360 degree sound field like speakers. All a headphone can do is present the range of frequencies clearly and in a balanced manner, so the small aural cues that indicate distance embedded in the recording- specifically bounce back and reverb- are clear and present. A flat frequency response does this the best because coloration in the wrong frequency range can introduce auditory masking blocking frequencies an octave above. I had this vividly demonstrated to me by an engineer friend. He played some music for me and boosted the mids at 1-2kHz about 4-5dB. Suddenly, the treble around 3kHz became muffled like a pillow had been put over the speaker. I would have never guessed that a boost in one spot would affect a completely different range, but hearing was believing.
If the bounce back thud off the wall behind the snare drums sits around 1kHz, a boost at 500Hz would be disasterous to the distance cues. A typical 3kHz upper mid boost makes the high end of the treble on the cymbals disappear, so the frequencies above that have to be boosted to compensate. That's why when you see response curves of headphones, there are always images of rocky mountains on the right side of the chart. It isn't easy to balance the high end. Most headphones have to settle for kludges to get them to sound OK. The same is true of the low end... Most headphones don't have balanced extension down to 20Hz, so they boost at 80 to fill in the gap.
I have a pretty good idea of what a neutral headphone sounds like. The Oppo is one of them, as is the Paradox. I was comparing the two to each other, not to all headphones. No headphone is perfectly flat, yet this phrase gets used every time a new headphone comes out to help add coal to the hype train. A few headphones off the top of my head that were described as "perfectly balanced" upon launch: LCD2, LCD-X, HE-6, HD800, SR-009, etc. Look at the graphs of the LCD2 and HD800 and tell me how those could possibly both have perfect frequency response. Upon listen, the LCD2 is clearly lacking treble and the HD800 has too much. I don't think the Oppo is as far off, but to suggest the FR is perfect is more of a pipe dream than reality.
I'm not sure what the soundstage tangent is necessary for, but when people refer to 'soundstage' on this forum it's not hard to understand what they mean. No, they don't throw out a soundstage at you the way speakers do, but if you've listened to more than 1 or 2 headphones over $100 you'll understand what 'soundstage' means on Head-Fi within a few minutes. Listen to a HD800, SA5000, K1000, or Stax Lambda and compare the way the sound space is presented to a DT-48, LCD2, SR-80, etc. There's a very clear difference, and it's not related to frequency response. Do you think angled drivers are for looks? Soundstage in headphones is a function of many things: distance of driver to ear, angle of drivers, open or closed, pad design, type of driver, amount of damping on the backwave if planar, etc.
Most modern orthos and electrostats actually are flat to 20 Hz (or very close to it). Dynamics typically roll off as you describe, but a sealed ortho/stat of appropriate driver area is flat. This has been demonstrated many times.
Originally Posted by bigshot
Well there is no audible distortion. That's pretty much a given considering the planar design. Sound stage I just explained. Speed and decay are a part of the recording. PRAT is a part of the music itself. Headphones are a thousand times faster than the typical reverb and decay and a hundred thousand times faster than the rhythms in recorded music. The dynamics on the Oppos is fantastic, again because of the planar design.
I think the problem is that "flat response" isn't understood by most people because they have never heard flat reponse, and wouldn't know it was flat if they did. When you work a bit with equalizers and carefully refine response curves, you find out that "treble being comparable" most definitely *does* mean that the treble sounds the same between different transducers. Frequencies are what we hear. The balance of frequencies is what makes one set of headphones sound different from another. You can take really good headphones capable of a flat response and EQ them into sounding like any other set of headphones. I've done this myself.
Over the past few decades, technological advances have pushed distortion levels, dynamics and noise floors far below the thresholds of human perception. The big wild card is frequency response. The more you know about frequency response, the more you know about high quality sound.
Speed and decay are part of the headphone. This is why CSDs are so useful. A perfect headphone would have no decay and would add no extra sound to the input signal. Physically this is impossible to achieve with moving mass, but as with everything we discuss some headphones do this better than others. There is more to speed than being able to play a 20Khz tone. Listen to any Stax headphone and compare it to your traditional dynamic and you'll hear exactly what a difference transient speed makes. Remember, music is a much more complex signal than sine sweeps so the effect gets multiplied many times over. This applies to the decay as well...just because one string on a violin may stop vibrating at a certain point doesn't mean it ends instantaneously in the headphone's cups when another string starts to vibrate. Headphones with cleaner CSDs are usually described as clear for this reason.
You can NOT transform one headphone into another simply by matching FRs. You can get much, much closer than they originally were but there is more to sound reproduction than FR. I agree that FR is a huge deal (probably the biggest), but it's not the only thing that's important.