I Love These Headphones...The NAD VISO HP50
NAD VISO HP50 ($299)
For those of you looking for a great all-around headphone, run, don't walk, to your nearest NAD dealer and get one...right now.
Not convinced yet? Okay, I'd be happy to go on for a little while about why this headphone is simply a game changer. We'll start with Paul Barton...
You may have read my recent article on the work done by Sean Olive et. al. at Harman Intl. on developing a new headphone target response curve. In it, I describe the great lengths to which this research team has gone doing the detailed work needed to carefully develop a pleasing headphone response by both objective and subjective means. This very careful study is slowly but surely coming to the conclusion that headphones should sound like speakers in a room, and a target response curve for headphones is slowly coming to light. Dr. Olive is proceeding with this very methodical work in an effort to conclusively establish a new headphone target response curve for the audio engineering community. Much of Olive's work and methods rest on research done at Canada's National Research Council in the 1980s, which was aimed at finding pleasing loudspeaker target response curves. Floyd Toole lead the team of researchers at the time; both Sean Olive and Paul Barton were involved with the project.
While Olive's current work is designed to bring a new standard into the body of knowledge for headphone designers and must be extremely methodical toward that end; Barton is under no such onus in his work designing product for PSB and NAD. His job is simply to make a good sounding headphone. That's not to say Barton doesn't do careful and methodical researchhe certainly does and, in fact, has participated in some recent strides developing a better ear-canal simulator that improves the accuracy of high-frequency measurements for headphonesbut it does mean that he can make some assumptions about headphone response (like they should sound like good speakers in a good room) and move directly toward finished product. Such is the difference between pure research and product development.
Barton makes these assumptions with a lot of solid information in his head, however. First, he knows one heck of a lot about what a good speaker sounds like in a good room. And second, he has an expert grasp on acoustic couplers and how to measure headphones. Combine these two skills together and you've got a potent brew for developing some great sounding cans. I've spent quite a bit of time picking his brain on his thought process, and the development of PSB and NAD's "Room Feel" technology.
Basically, if you take a direct radiating speaker that measures flat in an anechoic chamber and put it in a room, you'll find that it will have a significantly warmer sound. This happens because as frequency gets lower, the speakers radiate more omni-directionally, and therefor, the sound power content in the room as a whole gets stronger as frequency get lower. While this increase in low frequency response is somewhat decoupled from our perception of the sound from the speakers, it remains an important part of our impression of what a good speaker system sounds like.
In headphones, of course, there is no "room response" in the equation, and designers have typically either attempted a flat response into the lowest notes or added a big bass hump to satisfy bass lovers, but no real thought has gone into making a headphone response match that of the typical low-frequency boost heard in a good room. Here Barton's long expertise in matters acoustic come into play, and he has developed a very well reasoned headphone target response curve that takes into consideration low-frequency room gain and a number of other characteristics of a speaker's sound in a room, which has been labeled "Room Feel" by the company.
Paul and I both await Sean Olive's final headphone target response curve with baited breath. He because he's pretty darn sure the NAD VISO HP50 is right on target, and I because after hearing Paul's latest take on "Room Feel" have got to believe that tuning headphones to sound like good speakers in a good room leads to a darned good sounding headphone, and I'd love to have a better compensation curve for my headphone measurements than the one I currently use.
Alright, let's talk about these cans...