Stax Omega2 Mk2 Review

Frequency Balance, Range

The Omega2 has a dark sound signature, similar to what I’m hearing on the Sennheiser HD650. The treble is very smooth, far from sounding offensive, and since the background is very quiet, you don’t really need to boost the treble to hear the details in the music. In fact, the Omega2 is very good for low level listening.

Moving down from from the treble, you have a full bodied midrange that’s just as smooth and very transparent as well. Then it extends down to a full upper and mid bass. Bass punch is quite strong, roughly almost the same as the HD800 (give and take depending on amp combination). The bass is not boomy (of course no!), but the Omega2 does have a slight bump on the lower midrange to upper bass area, and it’s very strongly felt as a hump.

One of the most noticeable change from the SR-404LE is low bass performance, where the SR-404LE still can’t go very deep on the lowbass. However, the extension to low bass is not as linear as that on the HD800, nor does it extend as low.

While listening to the Beethoven Symphony No.9 by the Berlin Philharmonic and Claudio Abbado, a DDD Recording by Deutsche Grammophon, I also noticed that that the Omega2 is less extended in the treble and the bass, and less detailed than the HD800. Frequency extension and detail level have been quite an issue on all the electrostatic and older orthodynamic headphones I’ve heard. It seems that the faster transients and the blacker background on the planar headphones gives the illusion of very good detail, where it actually is the faster transients doing a great job of playing busy and complex passages. Of course, I never expected this to be an issue with the flagship Omega2. But on slow passages, like the 3rd movement of the 9th Symphony, the difference on frequency extension and detail is very noticeable between the HD800 and the Omega2.

Sometimes a small treble roll off can be preferable, as long as it is not too extreme. A slight roll of on the upper treble can be more pleasing to the ears, and even works to cut off any sibilance present in the recording. Likewise, a slightly less detailed presentation is not as big of a deal as it looks on writing. The Omega2 is living proof for this. Despite the shortcomings on extension and detail level, the presentation of the music is far easier to like than the HD800. The frequency balance might not be too flat, yet it sounds very good on the ears, and I think that’s all that matters. I do feel that the Mk1 version, supposedly without the upper bass hump, would be more fitting for a reference headphone like the Omega2.

Soundstage performance

The most striking difference between the Omega2 and the HD800 is the very black background that I hear on the Omega2. On a world-class concert hall, one of the things that accoustic engineers note is how quiet the hall measures. Most classical concerts doesn’t use active electronics to amplify the sound, and the quieter the hall, the clearer you can hear the sound of each instruments. Upon this very quiet background, every instruments come out like rays of light on the blackness of the stage. The experience is quite breathtaking.

The soundstage of the Omega2 is not as wide as the HD800, and the Omega2 actually feels less open than the HD800 or many other open design headphones. By itself, the HD800 with the Beta22 amplifier has a very good instrument separation, yet the HD800 lacks the quiet background that I’m hearing on the Omega2 that makes the instrument less clear separated on the HD800. The black background of the Omega2 sometimes makes me feel that the HD800 has an imprecise separation. Upon longer listening, I noticed that the Omega2′s soundstage portrayal is not very realistic. Naturally, when I play a recording such as Beethoven’s No.9, the orchestra should be laid very wide in front of me, with each instrument group taking a place in that soundstage. The stage can be panned very wide to the left and right, but it’s only natural to have the stage positioned in front of you. With the Omega2, upon the black soundstage, the instruments don’t originate from one stage in front of me. Some instruments can sound from very hard panned left, some from the top of my head, and strangely, almost nothing from the front. I do think that the Omega2 sounds more impressive overall, mainly due to that black background, but after long listening periods, I do miss having the stage portrayed clearly in front of me.

In comparison to the Lambda staxes, most notably the SR-404 Limited Edition, the Omega2 soundstage performance is quite far ahead of the SR-404LE. The primary difference betweent the two seems to be that on the SR-404LE, the left and right soundstage is fairly disconnected, where on the Omega2 it’s more coherent. Additionally, the SR-404LE doesn’t nearly have as black background as the Omega2, and the instrument separation is not as good as on the Omega2.

Vocal performance

The Omega2 has a full sounding midrange and has great clarity. This naturally is a great recipe for a great vocal reproduction, and indeed it is. For smooth female vocals, the Omega2 has the perfect reproduction in terms of body, presence, focus, and smoothness.
In comparison to the HD800, the Sennheiser has just as good of a vocal performance, though slightly different in character. On the HD800, vocals have a heavier weight while still maintaining clarity, vocal texture is better on the HD800, and has a better center focus on the soundstage. Having a more linear top extension does make the HD800 more transparent to any sibilance in a recording, where the Omega2 is fairly safe from it.

If you like your vocals to have a rich texture and listens to a lot of live recordings, then the HD800′s rendition is better for you. If you avoid sibilance, like a smooth vocal presentation, and has many closed mic-ed studio recordings, then the Omega2 would be preferable.