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.

Rate this review

  • Matt

    You made it sound like the omega 2 was the end of the road at the beginning of the article but by the end you made it sounds like you prefer the hd800? Was there any definitive winner in your book?

    • Hi Matt, I'm glad you asked that question. Sometimes writing reviews, gosh, are not easy, and I may lead people to the wrong impression. I probably need to edit my conclusion there.

      I pointed out that the Omega2 has a limited extension (top and bottom) in comparison to the HD800. Detail is also less, and the thing with the soundstage coming from all around you but not the front. But I also said 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 also want to quote the introduction part, where I said:

      As the flagship STAX headphone, the Omega2 is the most perfect headphone I’ve ever listened to. All of us can start from different headphone preferences, and ultimately we would end up with the Omega2 as the ultimate end of all headphone. At this level, there is no more dynamic vs electrostatic debate. The Omega2 reigns supreme at the top of the food chain.

      I think that's the highest praise I've given any headphone. Despite the technical shortcomings, what matters is how it plays the music. I can tell you that if I play a random playlist to ten people, 8 of 10 will probably choose the O2 over the HD800. It's just that good.

      The conclusion is not very positive, true, and that's probably what gives you the negative impression. Should've ended the article a different way. Again, thanks for the question. I do appreciate you asking that.

      • Matt

        Thanks for the detailed response Mike. I think the new ending does a great job of summing it up.

    • I added some stuff to the conclusion, to avoid further confusion. I also added some small stuff to the part about the Frequency Balance.

      • Jose

        Very nice review Mike. Thanks for doing such a great job every time!

        • Thanks Jose. We strive because of support from people like you. 🙂

  • Ian

    Thanks for a great review. I've always wanted to try Stax gear but been frightened off by the cost which you mentioned in the concluding paragraphs. Just waiting to see comments over the next few months for a couple of new developments:

    * New headphone from Stax – SR5-7 –

    * Woo Audio's Electrostatic Energiser –

  • manaox

    Nice review Mike, thanks for taking the time to write a detailed review and comparison.

    • Hey dude, haven't seen you back here for a while. Been busy with other things?

  • Budi

    Mike, thought I may want to chip in a bit. Your article said that Mk2 solely available in black. This is not particularly correct. The black Mk2 is for export product whereas for domestic Japan, the Mk2 still comes in champagne color housing and brown cable. Just wanted to clarify

    • Thanks for the info, I'll add it in!

  • Budi

    Mike, my apology, it actually comes in silver color for domestic market. Attached is the link

    Export market remains the same ,black on black pads/cable. Once again my apology

    • Thanks dude. I didn’t even check the website because I thought you’re the O2 expert. 😛

  • Ahok

    Tried this yesterday, (soooo late lol)
    and im pretty much agree with mike, that this is a more preferable headphone to most people, because its signature is easier to preceive for many people, 
    and played most genre yesterday, from rock, to classical to j-pop, 
    all songs played by the omega2 flawlessly, 

    I also have the chance to audition the SR-009 (yeah), side by side with the SR-007Mk2, 
    driven from the SRM-007tII, 
    even though the technicalities on the SR-009 is slightly better, slightly here means the difference is really small, (a bit better soundstage and extension), 
    I prefer the darker sounding SR-007Mk2, as its very relaxing to hear, the brighter and less bodied SR-009 is not as relaxed as the 007Mk2

    • Anonymous

      Awesome review there man. 😉

      You know after the LCD-2 is released I think it would take a lot of people away from the O2. Tonally very similar (the version 1 at least), and though it’s not quite electrostatic-smooth like the O2, the bass is just phenomenal, and it doesn’t require a $2000 amplifier to drive. And at the end, bass remains the #1 problem I see with Stax headphones. Especially more that our music these days tend to be beats-heavy.

      • Ahok

        yeah, LCD-2Mk1 is very similar tonally wise to the O2Mk2, 

        the LCD-2 is a steal for its price, for its phenomenal bass, simplicity of its setup, and the level of sound it produces, 

        i think the LCD2 is more suited to nowadays beaty music than the O2, which has narrower genre bandwith, although i have no problem playing j-pop music on the O2Mk2, 😀

  • Chevrol1

    This review is a joke.
    How many times did he wrote “black background”?
    What is a black background, is it absence of noise or what? If so, how many headphones noise by them themselves?
    ” you know that you’re still not using the best amplifier there is for the Omega2.” -about SRM-717.
    Ok, says who? Any independent test results that confirm this?
    Actually, Omega2 might be the best headphone in the world, I don’t know, but this kind of bullshit and nonsense isn’t useful for anyone.

    • Yes I was just joking and this article is a total bullshit.

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    the same amp that you suggest for the audeze lcd 2-3 ,is also suggested by you to pair the stax Omega2 sroo9 ?

    in other words its BHSE or alo 6 or somthing else ?

    • Dave Ulrich

      Electrostats usually require a special amplifier

    • No the Stax headphones need a different type of amp.


    which one you suggest ?

    • I like the WA5 + WEE combo


    sound wise they do better then BHSE ?
    just bringing that one up again ,since seen many prefer that for their stax

    • Yes best set up I’ve heard


        thank you ;
        recently have came across ,some reviews saying that lcd-xc by audeze with the wright amp ,they get almost the same quality sound ,as stax 009 with paired BHSE ,i asked them and waiting whether respond will come ,my question ,stax 009 as electrostatic can only be better in transparency and detail ,but sometimes thats a minus ‘since it gives a very analytic touch to the listener ,while audeze lcd x should be the better in the sound signature that you always prefer ,’which is warmness and joy ” am i wright ?

        • The Stax sound is unique and it’s a nice sound to listen to. The problem is ultimately Stax just can’t deliver a decent bass even from the BHSE. Planars are taking over as it’s very easy to get the bass out of planars.
          And what music these days don’t require bass?

          • STARSTERN

            BHSE with Psvane EL34PH’s tubes !?