The Sennheiser HD650
The HD650 has received a lot of inaccurate branding, and it’s probably one of the most mis-understood headphones. One term that we associate the HD650 heavily with is that it’s dark and veiled. The reason that a dark presentation is preferable for music listening is due to the nature of music recordings. It’s no secret that most recordings are prepared for speaker playback. As you know, speakers sit at quite a distance from the listener, and because high frequencies get attenuated faster as it travels through the air, the recordings must attempt to compensate for the treble attenuation by adding a slight boost. On a headphone set up, the drivers sit very close to the ears and there is no treble attenuation from the air. As a result, recordings that sound right on a speaker often sound too piercing on a headphone. For a monitoring headphone, a neutral with a slight tendency to bright is probably fine, since the engineers need to have a zoomed-in view to the record. But for music listening, a dark headphone is most often preferred as it gives a better presentation for long term listening.
A lot of flagship headphones actually take on the dark stance, such as the Stax Omega 2 (Yes! The king of headphones is a dark headphone), the Audez’e LCD-2, and even the JH16Pro all belong to the darker sounding group. Likewise, the old kings of the vintage orthodynamics, including the Fostex T50v0, the NAD RP18, and the Yamaha YH1000, are mostly dark in their presentation. It’s interesting that as I compared the JH16Pro to the HD650 side to side for this article, I find the JH16Pro to be darker with less treble and more bass presence than the HD650. But the JH16Pro, as well as the other flagships, have never been blamed for their dark sound signature the way the HD650 often is.
My attempt to explain this phenomenon would be the components surrounding the headphones. At the level of the Omega2, the LCD-2, the buyers would always set aside a serious budget for a high end amplifier and a high quality source. The Omega2 doesn’t work out of a laptop headphone out, and likewise nobody would be plugging in the LCD-2 and the HE-6 into an onboard soundcard. The HD650 is different. You can get it on the streets for less than $400, and the buyers often don’t want to spend another $400-$500 for an amplifier. Well, the HD650 is dark, veiled, and very boring when underamped.
Once you start using good amplifiers like Woo Audio’s WA6, Burson’s HA-160, Lehmann’s Black Linear, or Grace’s m902, then the HD650 starts to really show its potential. The headphone awakens, and one of the thing that you notice is how it is not as slow and as boring as it was before. The nice thing about the HD650 is how it remains the only headphone among the three that can scale up very well, even close to the level of the $1,000 flagships. For instance, I don’t quite feel that the DT880 and the K701 has enough scalability to be paired to top end amplifiers like the Zana Deux or the Beta22. They improves, but it’s like they’ve hit a limit earlier down the road. On the other hand, the HD650 truly sings on high end systems, as I still enjoy the combination of a HD650 with the Beta22 very much, even while having the Hifiman HE-6 and HD800 around.
If we were to look at it from a different point of view, the Beyer and the AKG do give a more predictable sound and are less dependent on the components behind it. This is nice for newcomers, as they’re instantly rewarded with a great sound upon the purchase of the headphone. The HD650, on the other hand, can be very slow or very dynamic depending on the system it’s hooked up to. This may explain a lot of the conflicting impressions to the HD650. Some people would like to spend $300 on a headphone and be done with it. Some other would like a headphone that will continue to improve with every better components they buy down the road. So, this may be a good or a bad point, depending on where you’re looking from. I’ve personally have never heard of a bad report concerning a HD650 & a balanced Beta22 pairing, and this shows how tremendous the HD650 changes as you upgrade your chain.
One of the most controversial aspect of the HD650 is in its bass. People have gone into very intense discussions about HD650’s bass. One one hand, the weighty bass is very pleasant for music listening, and as I said earlier “midrange and bass lets you feel the music”. However, some people find the bass too muddy and too thick, contributing to the overall sense of slowness in the headphone and how it cannot keep up to faster paced music. The bass weight and punch is definitely one of the major score of this headphone, as it handily beats the K701 and the DT880 in this area, but in all fairness, the HD650 does struggle with presenting a good clarity and texture on the bass region.
With more powerful amplification such as the Grace m902, the HD650 improves on the bass clarity as it also picks up some speed. (I don’t mean speed as in transients, but rather, the ability to carry the pace with fast-paced music). It even carries the pace quite well with aggressive music such as Muse’s Uprising or Rage Against the Machine’s Evil Empire. With the Beta22 and balanced drive, the HD650 is even quicker, and improves the bass texture even more. However, at the end, the speed is still a tad behind the K701 and bass texture is far behind the DT880. So, in that sense, the HD650 is not the best headphone to choose if you like very fast Rock or Metal, but it should be fine for stuff like U2, John Mayer, the Beatles, and such. The DT880 actually has an ideal speed, pace, and control for such genres, but its excessive treble will cause serious problems as most of these recordings tend to be quite hot on the treble. As it is, none of the three headphones actually work for fast Rock, and we need to be looking at the Grado RS-1, Audio Technica AD2000, or the Hifiman HE-5 for that.