I have the Etymotic ER-6, the Stax SR-003 (the earphone that comes with the SR-005 system), and the Stax SR-404. I use the ER-6 at the gym and on the train. I use both the SR-003 and the SR-404 at home. When traveling I take the SR-003 with the SRD-P (a battery powered pro amp/adaptor with 8 C Cell batteries and two 5 pin plugs). This is the most satisfactory portable set up I have ever heard.
First, the SR-003 is nothing like an Etymotic. It does not have the isolation characteristic of the canal phone. They do not isolate much at all, not enough for the train or the airplane. The SR-003 is an open electrostatic design. Because the driver is small in size my wife does not complain about the sound coming out of them. At first I used them with the headband and they were very acceptable. I have since discarded the headband and now use the “lick and stick” method of getting them into the ear canal. I need to use one medium size ear pan and one large size.
Once placed in the ear canal they are nothing short of stunning in terms of their musicality. The bass is quick and taunt but still full and rich. They do not however have the visceral “slam” that many here prize so highly. They do go fairly deep. Mids are transparent, well defined, and really nice to listen to. Voices, strings, and acoustic instruments are presented effortlessly. People say that the highs are rolled off. I think that violins, cymbals, triangles, and gongs all sound the way they are supposed to. Music in general has a sense of immediacy and they have a great detail; two qualities that I highly appreciate. Drivers are well matched or at least appear to be so. They also give a fairly good illusion of instrument and belie their dimunitive size. Foot tapping factor is really high! I think they rock!
The most impressive characteristics are their dynamic range and the ability to reproduce multiple instruments. From the quietest passage to the loudest crescendo they play without a sense of strain or distortion. They have the ability to play very loud (in excess of 115 db at certain frequencies) so be wary of your hearing. The number of instruments in a small ensemble can easily be counted and they do not appear to be reproduced as an amalgamation.
On the downside, they took about 2-3 weeks to really break in. At first the midrange was smeared and kind of ill defined. They were also somewhat uncomfortable at first, this has since become a non-issue. They require the 580V bias voltage to energize the electrostatic plates. The unit with the SR-005 has the standard 5 pin plug. It is however not portable. The SR-001 is portable but has a non-standard plug. The cable on the SR-003 (or SR-005) is also very short, be sure to get an extension cord. They also do not like to get wet.
IMHO they are the greatest bargain in terms of getting a glimpse of the high high end and may be enough headphone for some.
Thank you both for the responses. So it looks like these phones do the midrange right. For the total price of little over three hundred, it does look like a real good deal! I just wonder how they would handle rock....
I have not heard the amp with the SR-001 system. I use an SRD-P and have an SRD-X on the way from a used item store with the SR-003's. I think the sound with the SRD-P is really good for a portable set up. Tons of gain and uses the standard 5 pin plug. Only problem is that it requires 8 C cell batteries and therefore is on the heavy side.
With regard to comfort, I have gotten used to the way they feel. I highly recommend doing away with the headband and sticking them into the ear canal. The bass is fuller sounding and overall balance is more pleasing. I can also wear them for a couple of hours without discomfort.