When I gave iFi audio my first feedback on the setup’s sound, the Sennheiser HD660s wasn’t in their Synergy overview yet. I told them how much I liked the HDXX setting with it and how strong the difference in sound was. Then with the next update of the table, the Sennheiser HD660s was included in the overview. It’s actually very normal this unit is on the list because it’s the unit with which I find the impact of the setting to be the biggest.
Like with the HD650, you either love or hate the HD660S. I for one really like them, but then again I’m a big Sennheiser fan in general. This actually is the headphone I liked the 3D-setting most on.
The bass boost combined with the rest of the modifications really works well for the HD660S. While iFi audio gives it a very good synergy rating, it actually for me is the headphone I like the effects the most on. Even more so than with the HD660 and HD6XX headphones. The bass presence, vocal energy, dynamics and musicality: it all works well with this combo and while I almost never listen to the HD660s, I kept going back to this headphone with the Signature combo.
Of course we don’t have the time to try all headphones in our collection but we did try some like the Beyerdynamic Amiron (great result, full sounding), the Audeze LCD-2 Classic (bloated bass), Kennerton Wodan (bass too overpowering), Meze Empyrean (bass monster but in the best possible way/fun), Hifiman Ananda (bloated and too much bass) and the HEDDphone (big bass, softer vocals).
The results of the HD6xx EQ settings are very different on all these headphones. For some they work (really well) and for some they don’t (at all), it’s a bit of the typical miss or hit but more of a miss so far. The HD6XX setting are developed for Sennheiser so it’s really the headphone brand to use if you want to profit of the HD6XX EQ setting.
But even if the HD6XX EQ setting isn’t the best for your headphone, the iFi audio Signature DAC and AMP still have an incredible value as “normal” DAC/AMP.
The higher priced iFi audio ZEN DAC and CAN Signature units still offer good value for money, especially if you’re planning on using it with any of the Sennheiser headphones mentioned in the overview. At the same time don’t expect this $500 USD stack to blow all DAC/AMP combos away as that’s not realistic.
Once I experienced the HD6XX settings on the ZEN Signature combo, it for most Sennheiser headphones was hard going back to the normal sound of the stack. I do feel iFi audio got it right for Sennheiser. For non-Sennheiser headphones this might not be the best solution, but that shouldn’t come as a shock as this was their focus.
The full review of the Signature series will come once these units are widely available and then we’ll of course cover all the topics we normally touch in a full review, and not just the part on sound.