Sennheiser HiRes Audiophile Headphone (HD 660 S)

Product Information

In this, and the following series of photos, the HD 600 is at left, the HD 650 at center, and the HD 660S is to the right. The basic signature can be described as slightly dark compared to something fully neutral, but not overly so. It is warmer and more musical than something like HD600, it has more detail, more clarity, and it has better definition than HD650. It would be more of a headphone to satisfy both the users who love HD600 and those who love HD650, bringing forward the best of both worlds.

Unlike the Momentum series, which has punchy sub-bass as its calling card, the HD 660 S have tightly-controlled bass. The frequencies are there, but so is the reserve expected of a higher-end headphone. To make up for this, the headphones delivers a little more power from fairly up-front mids.What more can I say? We have the same built and design that we are familiar with for more than 26 years. These days, portable headphones tend to be at the top of most buyers’ to-buy lists. However, the Sennheiser HD 660 S prove full-size open headphones such as this are generally a better choice if you simply want a pair to use at home. The uild quality includes mostly plastic, Sennheiser HD660S has some other materials that are not plastic, like for example the drivers, or the grills on the drivers / the padding, but this shouldn't be taken negatively, since there are plastics that can resist to extreme amounts of weight and pressure. These headphones have that same lower-mid range richness, but also have a little more high-frequency treble energy to balance it out. Listening closely, this added zing can come across a little “modular”, making the signature a little less of a coherent whole than, say, that of the classic AKG Q701. However, as long as you’re here for enjoyment rather than pro-style sound monitoring, you can interpret the Sennheiser HD 660 S as a bit of a “greatest hits” of the Sennheiser HD series. The mids again are very similar, with the HD 660 S being a bit cleaner and better defined. I can hear the string vibration and the decay of the vibration more clearly, the HD 600 masking these subtle details.

Build quality seems similar to the HD 650. Plastic doesn’t offer a luxurious feel, but the quality of the plastic used is excellent. These headphones are built to last. Cups and cables can be removed and replaced too. The padding in the new HD660 S feel very firm to the touch and offer a really nice level of both give and support. This may be because these are a brand new pair and my HD650 is, how should I say, well experienced, the padding looks to be a little bit deeper than my ol faithful HD650. This is a good thing because my ears no longer touch and rub against the cloth covering the drivers. Like I told you, the HD 660 S is only 2dB more sensitive than the HD 650 and HD 600, so the halved impedance has very little impact on this.

In my opinion, the HD 660 S is the true reference in the HD 6xx line, with the HD 600 coming second and the HD 650 coming last, with a more colored sound.