STAX 007A - COMPARISONS WITH OTHER PHONES - STAX 404 and SIGMA/404
Nov 17, 2008 at 4:00 AM Thread Starter Post #1 of 48

edstrelow

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STAX 007A COMPARED WITH STAX 404 AND SIGMA/404

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The Stax Omega series, which began with the original Omega in 1993, the Omega II or SROO7 in 1998, and the SR007A which came out about 2007, are probably the best and certainly the most expensive Stax phones available. They cost 4 to 5 times as much as the next most expensive model designed for home use, the 404, (The 4070, which is based on the 404, is a closed studio monitor, not as widely used as the 4040 and sells for about 3/4 the price of an Omega).

Having owned the 404 for about a decade, I was reluctant to pay the Omega's premium price, especally given the checkered history of the Omega's, with the first and second models needing redesign but the latest the 007A being subject to squables as to whether its performance is better or worse than the second 007.

Nevertheless I finally bought into this line, with the 007A and I thought it might be worthwhile to contrast its performance with the 404 and to some extent with the Sigma/404. I presume there are the many owners of 404's and other Stax Lambdas who are still debating about the benefits of such a costly move-up just as I did. As well, I made comparisons with a Sigma with 404 mods. If anyone wants to compare the Omegas with the other stats such as the 4070, Lambda Signature, Sennheiser HE90/60, Koss 950, or various dynamic phones, you might want to do so in this thread.

LISTENING EQUIPMENT

My listening set-up used a CEC 5100z as a CD transport, feeding a Monarchy jitter reducer and a Musical Fidelity A324 DAC. Tweaks include upgraded power cables, sorbethane footers and silver interconnects. I also use Silclear contact enhancer throughout the system, including on power plugs. The amp is the Stax 717 transistor amp which seems to be generally accepted as the best of the Stax transistor amps, there being some people at least who don't like the 717's replacement the 727 series.

DISK TWEAKS

I am also a disc tweaker, all my CD's are machine polished with Mapleshade Microsmooth, and edge-trimmed with the Desk Systeme, which is essentially a lathe which trues the circularity of the disc and puts a beveled edge on the dics. My discs are also polished with Auric Illuminator and the edges blackened, The discs are weighted with various disc attachments, such as Alsop rings, disc protector or Audioquest rings. The general effect of such disk tweaking is, in my opinion, to improve detail, imaging and bass and may have some bearing on my comparisons of the various phones although I doubt that the comparative results would be different with untweaked cd's.

THE MUSIC

I listened to a variety of popular and classical recordings. For pop I compared Credence Clearwater Hits, Pink Floyd's The Wall, and The Momas and Popas hits. For folk I used Joan Baez' Spanish Songs, and for choral music, a little-know Analekta Canadian live digital recording of the old Soviet Army Chorus, (which I assume like the Soviet Union, no longer exists. I had heard this group perform in LA shortly before its demise and had some sense of what it sounded like live.) Classical choices were Phillips Mahler 6'th Symphony, and the old Angel/EMI Karajan recording of Der Rosenkavalier.

WARM-UP/BREAK-IN

Before I dd any comparative listening, I ran the system with music playing for at least an hour. Also I had used the system with the 2 headphones, hooked up, at least intermittently for at least 3 days. My general feeling is that most Stax phones need about a 45 minute warm-up and repeated use over a number of days, with the phones being connected to their amplifiers, to sound their best.

007A VS 404 GENERAL OBSERVATIONS

The first notable difference between the 007A and the 404 was that the 007A was less efficient than the 404. The volume with the 007A had to be turned up almost about one notch on the 717's volume control to match the 404. The 404 shows an upper midrange peak which made them sound less balanced, or more colored, than the 007A. It also has somewhat of a deep bass kick or boom than the 007A. It definitely goes lower in bass than the 007A which has a less prominent bass peak a little higher in the frequency spectrum. Of course where the 007A excells is in detail, dynamics and a marked lack of coloration compared to the 404.

The Soviet Army Chorus is a large chorus with an orchestra which here was quite well-recorded with some magnificent large scale climaxes of solists, chorus and orchestra and makes a good showpiece/demonstration disc. It sounded good on the 404 with a tad more deep bass on bass instruments. The 007A was laid back by comparison but somewhat more listenable and refined. The details especially in the loudness peaks were better articulated with the 007A.

The opera was an early stereo recording of Der Rosenkavalier, which is still one of my favorite recordings. The bass was more peaky on the 404, with a mellow but somewhat thick sound by comparison with the 007A. On the other hand the tape noise was much more obvious with the 007A. I latter checked this recording out with a 10 octave equalizer and the hiss seemed to be concentrated at about 8KHz indicating that the 007A had a peak there. The 404's peak seemed lower in frequency and in consequence had a somewhat cleaner, darker sound. The 007A however resolved the soprano voices much better, there are soprano duos and trios in Rosenkavalier and I had never heard these sound as detailed with other phones.

On Mahler's 6th symphony, the drum strokes seemed a bit soft with the 007 compared to the 404 but otherwise the 007A seemed more tonally balanced. The 007A had with a more stable and wider soundstage and more detail. When the 007A was cranked up in vlume it became particularly impressive. The 404 sounded good in an immediate comparison, with a good sonorous lower midrange and bass range, but after a few seconds of listening, there was a sameness or coloration to the sound in the lower registers, giving a sort of "droning" sound with the 404 by comparison with the 007A.

The Spanish Songs of Joan Baez showed some recording problems on all phones. There was some bassiness which produced some one-note bass thumps with the 404, versus a broader, but less noticeable bass peak on the 007A. The 007A showed more air around the instruments and voices, and more precise spatial localization

I really like the recording quality of Pink Floyd's The Wall and feel that, like The Soviet Army recording, the first few minutes make are good demonstration material. Here the 404 had deeper bass but the 007a showed again a very clean sound, with better separation of instruments, a wider and better defined soundfield.

The Mama's and Papa's is another old pop recording with some hiss which was more evident on the 007A than the 404. The Credence recording was less noisey than the Moma and Papas. The 404 showed a somewhat more solid bass, versus a somewhat broad bass boom with the 007A. However again the 007A showed a mastery of detail, eg. the cymbal crashes were cleaner but sounded flattened or clipped on the 404. On balance the 007A was slightly more listenable because it had less edgy upper midrange.

SIGMA/404

I had an old Sigma modified some years ago by replacing the original drivers and cable with the 404 parts.

http://www.head-fi.org/forums/f4/sig...dphone-175556/

This makes a very nice sounding phone which is very listenable on a wide variety of music. As a pro bias Sigma it has better dynamics than a low bias Sigma and as a 404, it has better treble and detail than either the low bias or regular pro Sigma. But like all the Sigmas it has a unique spatial quality because the drivers are placed ahead of the ears, at right angles to the plane of the head.

It is even less efficient than the 007A needing to have the volume control cranked up about another notch. It is probably the most tonally colored of the 3 phones, due to its broad bass hump, and rolled-off high frequency characteristic of the original Sigma and Sigma pro and probably due to the unusual enclosure. I find the bass hump most evident before the set has warmed up. It seems to sound less colored after it has been on a while. Also the 404 has more treble than the two original Sigmas, due to the newer driver and low capacitance cable.

Its real strength is that it gives a more realistic presentation than virtually any other phones on the market. This is due to the fact that the drivers are away from and ahead of the ears. Unlike virtually all other phones, it sends no sound directly into the ear canal, rather sound is reflected into the ear canal by the external ear just like sounds coming from straight ahead.

I would not say that the Sigma fully solves the problem of getting headphone sound "out of the head," but it goes some way in that direction. By comparison, the 404 and 007A give a frontally collapsed soundfield. The Sigma/404 sounds very open, the others sound closed in and somewhat claustrophobic.

Compared to either the 404 or 007A it is lacking at the extreme bottom. In use however it performed very well with rock/pop music as well the Baez songs. It shows less hiss than either of the other 2 phones making it, like the other Sigmas, very good with vinyl.

The Sigma/404 has a very broad bass peak which to my ear compensates well for the lack of the bottom half octave, and contributes to the sense of drive of these phones. I have noticed this phenomenon before with smaller bookshelf speakers which compensate for their lack of deep bass with a similar bass hump. There is not always that much deep bass in rock/pop and the bass hump can make such speakers and these phones seem very rythmic.

Similarly the rolled-off top end means no edginess to the sound. I don't think you want a flat treble response in phones, because in real listening situations the treble response falls off with distance, so if you are halfway down the concert hall the treble is several dB down. When you add in the nearness of the microphones in most recordings you will end up with way too much treble if the top end is not rolled off on the phones. So the Sigma/404 ends up with an effective euphonic sound which makes a lot of different music very listenable.

It weakneses compared to the other phones are a certain mushiness of detail in the lower registers. I find the 404 to be generally superior with classical orchestra music. the deep bass and the mid range peak gives you a full auditory spectrum and more detail than the Sigma/404.

However I find the Sigma/404 as well as the normal Sigmas to be superior with choral and opera recordings. Possibly this is a direct result of the ability of the Sigmas to project sound somewhat more ahead of the listener. Certainly they are not perfect on that score but they do it more than any other phone I have heard and occasionally will trick me into thinking that I have left my speakers on. They generally recreate a sense of the ambience of a live recording of the voices which at least with classical music makes them sound more realistic than other phones. I suspect that I respond better to a voice being outside of my head. I mean there is something peculiar about having a person singing in your head. An instrument there is less obtrusive.


GENERAL OBSERVATIONS

I differentiate headphones, as well as other equipment, on two main categories, frequency response, including range range and flatness, and resolution. Frequency response means the range of audible sound which can be reproduced by equipment, roughly 10 octaves 20Hz to 20 kHz. Flatness referes to the neutrality of the frequency response, not having obvious peaks or dips which color the sound. By resolution, I mean the ability to differentiate and reproduce different signals so that different sounds really sound different.

FREQUENCY RESPONSE - RANGE

These days, even fairly cheap phones have a decent frequency response, being reasonably flat and with good treble and bass extension. Of the three considered here, the 404 had the best extension because of its extended treble and bass. This alone tends to make them seem realistic, as they cover more of the audible spectrum. The 007A had slightly less deep bass (these did not have the Spitzer blutack mod which can extend the bass) The Sigma/404 had the most restricted frequency extension, having the least deep bass and the most rolled-off treble.

Curiously while early reports of the original Omegas called them dark, suggesting a similar response as the Sigma, the 007A is not at all dark I would call them very neutral with a hint of bass boost just a bit higher up than the 404.

FREQUENCY RESPONSE - FLATNESS

I feel that the 007A was the best in this comparison. It seemed pretty neutral sounding, for some people, at least on first listening somewhat bland. The 404 has a bright upper midrange, which is somewhat overpowering on some pop/rock if it is already too bright. However, this characteristic generally helps it with orchestral music. The Sigma/404 is the most obviously colored of the three with the bass hump and declining trebele yet it is such a euphonic coloration that it is not objectionable and even helps make rock/pop sound more rhythmic.

RESOLUTION

Here is where the 007A wins hands-down. It just pulls details and dynamics out of music. The 404 is probably second in this respect and the Sigma/404 third. This is what you are paying the bucks for with the 007A. Aparrently Stax has succesfully implemented a audio breakthrough with the Omega's very large and solidly made drivers fitted to a rigid aluminum frame.

I found myself unable to listen to anything else for some weeks after I got 007A. Subsequently I did more listening with the Sigma/404, on a different system, where its more realistic soundstage and generally euphonic sound makes them very listenable.

Comfort wise, I prefer the Sigma/404. even though it is very boxy and awkward looking. It puts no pressure on the ears and is very cool. Both the 404 and 007a press on the head and ears. The 007 is the least comfortable of the lot and I am not thrilled by its swivelling ear pads. I don't feel that they need to be adjusted, whereas the head band, which does need to be adjusted, must be bent to fit, by brute force.

Nevertheless, the 007A is, as John Buchanan said about the 007, a "seriously great phone." My take on the 007A is that I have never heard anything pull out detail and yet still sound so listenable over such a wide range of music. However when I put on the 007A after the Sigma/404 and the sound-field collapses into 2 dimensions I would like something which could marry the Omega and Sigma concepts. What would be really nice would be a Sigma rebuilt with an aluminum frame and 007 drivers. I would hope that the aluminum would be less resonant than the current plastic frame. The 007A drivers might be just a bit too big to fit the Sigma frame, but you get the idea.

LAST EDIT
Long after I wrote the above I became aware that different users of these phones used different orientations of the D-shaped earpads. I started out with the curved portion going behind the back the ear (which is more or less curved) Other users suggest the flat edge should go behind the ear. I have tried both and prefer my first choice. I feel that pad orienation makes a significant difference to the sound and anyone trying these phones, should, if unhappy experiment with different orientations.
 
Nov 17, 2008 at 11:58 AM Post #5 of 48
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Thanks for the interesting read. I'll have a chance to compare the 007 and 404 with a 717 next week, which I'm looking forward to. I got the impression that the 404 was better with tubes, and the 007 better with transistors, something I intend to experiment with next week.
 
Nov 17, 2008 at 5:05 PM Post #6 of 48

krmathis

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Great reading indeed!
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Its no question that the Ω2 are in a league of its own compared to the Lambda series 'phones.
 
Nov 17, 2008 at 8:20 PM Post #8 of 48

HeadphoneAddict

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I have plaidplatypus's Sigma Pros here for loan. I have compared them to the Lambda and Lambda Sig and O2 Mk2, similar to this comparison.

I certainly can add my testimony that the Sigma Pro (not 404 drivers) is definitely rolled off and mids centric, to the degree that some instruments (triangle) are missing from some orchestral pieces I have listened to. The details really suffer as well.

I can also testify that they produce a cohesive front centered sound stage unlike any other headphones, with 180 degree wraparound, that can only be dreamed of by other headphones. Switching from the Sigma Pro to Lambda and Lambda Sig really does leave a big hole in the middle of the sound stage, although the O2 Mk2 are not as bad and the brain fills in the middle quicker after listening to the O2 for a while than it does with the Lambda which takes longer to adjust (partially due to recessed mids vs O2). But the Lambda sound stage is never as cohesive as the O2 Mk2.

The final observation I would like to offer is instrument placement. The O2 seem to do it in spades, while the Sigma Pro just blur everything into nebulous blobs here and there, and the Lambda and Lambda Sig are in between. The ESP950 and HE60 come closer to the O2 Mk2 in pinpoint instrument placement than the Lambda, with the difference being the HE60 are more etherial and airy like listening to a hologram, and with the ESP950 the instruments are more solid like the O2 Mk2 but more squished together than the O2 Mk2.

The O2 at first seems a little rolled off, but the brain accommodates and all the details are there to be enjoyed in full, but the Sigma Pro (not 404 drivers) never seems to fill in the missing details no matter how long they are on the head (at least up to 20 minutes at a time). The Lambdas just don't seem to have a flat enough frequency response to provide the full illusion of the real instrument being there, and one is often aware that it is just a very good sounding recording - sometimes I feel like I hear the sound coming from the Lambda's drivers but when I focus my attention on it then the sensation goes away. The Sigma Pro at least have the ability to make you feel like you are in the hallway outside of the auditorium where the concert is playing
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Nov 17, 2008 at 9:30 PM Post #9 of 48

Faust2D

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In my experience Sigma frame from conceptual standpoint is superior to all other headphone frames. You really get close to speaker like soundstage.

Quote:

With SR-Σ Stax attempted to recreate a natural, realistic sound field in a headphones format. After four years of development the huge Stax SR-Sigma series was released in 1977, followed by the SR-Lambda series in 1979. SR-Sigma design positions an oval driver at about 80 degree angle to the ear. This creates an illusion of sound field located in the front of the head not on the sides. Very large driver, large than the ear, allows the outer-ear to guide the sound into the inner ear thus removing the in the head effect.



The drivers are not up to part of providing the details and plastic just gives up at some point and fails to tame vibrations. With chamber music with limited instrumentation or folk music Sigma is unbeatable. I wish new Sigma with SR-007 class driver and some kind of light alloy frame would grace this earth. I bet it would kick ass in very serious way.
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Nov 19, 2008 at 10:19 PM Post #13 of 48

John Buchanan

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Ed, nice work!
As you know, I run a similar stable (LOL) of phones...errrr.....earspeakers - the Omega 2 Mk 1, The Lambda Nova Signature and the Sigma/404 run from the SRM-717.
Given that we have the common grounding of the Sigma/404, I was very interested to hear your comments regarding the sound of the Omega 2 Mk 2. In my comparisons, the Omega 2 Mk 1 does much better deep bass than the Sigma/404 and slightly better deep bass than the Lambda Nova Signature (and if the LNS has a similar deep bass to the 404, this gives some food for thought regarding the differences between the Omega 2 Mk 1 and Omega 2 Mk 2). I could quite happily survive with any of these 3, but the way I look at it is as follows......
(1) If you were listening to midrange centric music (especially choral music), or music recorded with a harsher treble and overblown bass, the Sigma/404 would be unbeatable. They need to be turned up loudish IMHO. They still pick up the purring of Tony Levin's Stick in the Projekct 1 Live At The Jazz Cafe CD very nicely. The Jecklin Floats rolled that sound off to inaudibility!
(2) If listening to very high quality recordings, or slightly rolled off treble recordings, the Lambda Nova Signature is excellent.
(3) The Omega 2 Mk 1 is in a class by itself and does everything very well - it is like a flattened frequency response Lambda Nova Signature and does brighter music better than the LNS, while still having a better deep bass. Ginger Baker's relatively soft (very deep) bass drum heard intermittently throughout "My Spanish Love Song" on Falling Off The Roof is more audible through this phone.
With summer a coming in, I suspect that the Sigma/404s will get more usage than the Omega 2 Mk 1, due to reduced heat retention and improved comfort.
 
Nov 20, 2008 at 7:16 PM Post #14 of 48

edstrelow

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Quote:

Originally Posted by John Buchanan /img/forum/go_quote.gif
Ed, nice work!
As you know, I run a similar stable (LOL) of phones...errrr.....earspeakers - the Omega 2 Mk 1, The Lambda Nova Signature and the Sigma/404 run from the SRM-717.
Given that we have the common grounding of the Sigma/404, I was very interested to hear your comments regarding the sound of the Omega 2 Mk 2. In my comparisons, the Omega 2 Mk 1 does much better deep bass than the Sigma/404 and slightly better deep bass than the Lambda Nova Signature (and if the LNS has a similar deep bass to the 404, this gives some food for thought regarding the differences between the Omega 2 Mk 1 and Omega 2 Mk 2). I could quite happily survive with any of these 3, but the way I look at it is as follows......
(1) If you were listening to midrange centric music (especially choral music), or music recorded with a harsher treble and overblown bass, the Sigma/404 would be unbeatable. They need to be turned up loudish IMHO. They still pick up the purring of Tony Levin's Stick in the Projekct 1 Live At The Jazz Cafe CD very nicely.
(2) If listening to very high quality recordings, or slightly rolled off treble recordings, the Lambda Nova Signature is excellent.
(3) The Omega 2 Mk 1 is in a class by itself and does everything very well - it is like a flattened frequency response Lambda Nova Signature and does brighter music better than the LNS, while still having a better deep bass. Ginger Baker's relatively soft (very deep) bass drum heard intermittently throughout "My Spanish Love Song" on Falling Off The Roof is more audible through this phone.
With summer a coming in, I suspect that the Sigma/404s will get more usage than the Omega 2 Mk 1, due to reduced heat retention and improved comfort.



I have often wondered why choral and opera sound so good on the Sigma/404 (and other Sigmas too) . The fact that the voice has a ;lot of mid frequencies may very well explain this since the Sigmas do these well and the treble roll-off prevents harshness.

Interestingly, I have been trying the Spritizer mods on the 007A (see related thread) and find that the spring modfication, seems to flatten the frequency response and extend the bass so that now my 007A seems to go almost as deep as the 404 which previously had markedly deeper bass. In this tweak, the 007As spring is bent flat like that on the 007, and the base of the spring is widened. Sealing the 007A's port gives a big boost to the extreme bass but I didn't like its effect on other aspects of the sound so I removed the port plugs after about a day. The spring mod is more promising and I am still evaluating it.
 
Nov 20, 2008 at 7:50 PM Post #15 of 48

HeadphoneAddict

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I don't see any reason to reverse the spring mod so far, after 4 weeks with the flattened spring.

I have had plaidplatypus and Sherwood come to listen to it that way and they both preferred the O2 Mk2 to the SR-5NB, SR-Lambda, SR-Lambda Signature and Koss ESP950. The HE60 is tougher to rank because they are polar opposites of the O2 Mk2, and their airy ethereal soundstage can sometimes be enticing because it is so unlike the other stats or dynamics on hand. Nevertheless, the O2 Mk2 have been getting more ear-time than the HE60.
 

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