STAX HISTORY PART 4

Stax SR-Sigma and SR-4070

SR-Sigma

STAX HISTORY PART 4 introduction

It would be possible to write a substantial amount about Stax and the Sigma series alone. This intriguing series warrants its own section in my story, but I won’t go into too much detail.

After four years of development and extensive trial and error, Stax finally unveiled SR-Sigma. The Sigma was conceptualised by Naotake Hayashi, inventor of Stax, with the intention of eschewing the immersive in-ear experience that other headphones provide. They positioned the drivers at a right angle to the ears, much like room speakers.

The SR-Sigma series deviated slightly from the other forthcoming Stax models due to this structure. Like I said before, you received a speaker-like sound picture when you positioned the newly-developed oval drivers from Stax in front of your ears. Furthermore, the SR-Sigma series is called “electrostatic panoramic earspeakers” because it provides an exceptionally wide sound image.

In 1977, the SR-Sigma was released; it was the first model to have the oval driver that would later be seen in the SR-Lambda series. The SR-Sigma had a normal bias of 230v and came with a black fabric cord. The cups have light-gray grilles and a 2-micron-thick diaphragm. While the treble is a little muffled, the middle is excellent, and the soundstage is quite expansive; the bass is nice, but muted, and there is no deep bass at all.

Stax SR-Sigma MK2

In 1979, Stax released the Sr-Sigma mk2, which was not officially an MK2 from Stax but was somewhat comparable to their current cables in that they swapped out the fabric for a flat one. When compared to the original, there is little to no change in the way it sounds. The driver that SR-Sigma utilises is also used by the first lambda.

Stax SR-Sigma Pro

This surfaced in 1987 and was a pro bias 580v model, as the name implies. It employs the same flat brown cable used on the SR-Lambda Signature with black grills on the cups. Black is the headband and assembly colour.

Stax advanced the oval drivers much more. The only two Stax models with a driver whose diaphragm thickness is just one micron are this and the Lambda Signature! This is quite special! Towards the end of manufacture of the SR-Sigma pro a few copies were given with drivers from the SR-404 Signature; this driver was quite costly and challenging for Stax.

Furthermore, the devices brought in for repairs matched the SR-404 Signature drivers. Though it is somewhat difficult to drive correctly, the Sigma Pro i noted for its very strong middle and bass reproduction. To properly value what these can offer, you should utilise a strong amplifier.

I should note that the SR-Sigma Pro arrived with a brown headphone stand, while the Sigma came provided with its own grey one.

Stax SR-4070

Stax’s second closed model after SR-50 Electret was the two versions of the SR-4070 series. The SR-4070 truly demonstrates Stax’s depth of experience in creating electrostatic headphones. You have a closed model here that sounds virtually exactly like Stax’s open ones. How they have accomplished this is absolutely amazing; you also get really strong bass reproduction. These were only offered as an ordered model and meant for usage in sound facilities. Their drivers are the same as the SR-404 Signature’s’. This surfaced in 2001 and boasts a 1,35 micron thickness membrane.

Stax SR-4070 MK2

Stax SR-Sigma and SR-4070

This version arrived about 2005 and had a fork fixed to the cup devoid of swivel or movement. This certainly is a design mistake that makes it a little harder to accommodate some people. Regarding sound, these feature extremely high resolution with airy treble, a big soundstage, and a very good and deep bass reproduction in line with the original.

Comments on the SR-4070

The design of the fork’s connection to the cup clearly distinguishes the MK2 from the first editions of SR-4070, which were delivered with a numerical serial number. The fact that the MK2 have a rather duller finish helps one tell them apart.