A lil' twt wit Heir Audio

For future reference. A lil twt with these God-forsaken Neanderthals, who still bang their heads against a tree stump.

Stax SR-lambda Professional: History revisited

Disclaimer: Measurement has been carried out with acoustic leak minimized, by using a silicone putty as a sealant.

Electrostatic headphones are said to have a wide sound stage, exceptional detail, and flat frequency response, easily surpassing the sound quality of any moving-coil headphones. Carl A. Poldy, the designer of AKG K1000 earspeakers, explains the basic principle of electrostatic drivers this way:

"The electrostatic transducer consists of a charged membrane, usually supported at its edges, and driven in an electric field modulated by the sound signal." 

Once the stators are charged, the d.c. polarized diaphragm starts to move towards the opposite charge, creating a sound wave in push-pull motion as the polarity is switched between the stators. Theoretically, the entire surface of the diaphragm acts uniformly at once in phase to the input signal, preventing a motion break, caused by uneven vibrational modes, from occurring. On top of that, the low-mass diaphragm yields a flat&well-extended frequency response and a fast transient characteristic.

However, in order to secure a linear low frequency response, tight seal is a must, according to the British audio engineer Peter J. Baxandall. Acoustic leak will most likely push the resonance of the diaphragm to higher frequency range, by cutting off the bandwidth in the lower end:

"...a given electrically produced force, at some specific low frequency, will now produce a much larger diaphragm velocity....the total stiffness is very much reduced, being only that resulting from the diaphragm tension and electrical negative stiffness."

Introduced in 1982 as a successor of the original Stax SR-lambda(Λ), SR-lambda Professional is the very first electrostatic earspeaker featuring 580 V bias(professional) voltage from the manufacturer. With the diaphragm 0.5 µm thinner than that of the predecessor, the manufacturer claim distortion has been reduced dramatically.

Moreover, this very headphone is an important piece of history of the headphone industry, as it has been featured in numerous research papers, including the well-known study of 1985, which helped standardize the diffuse-field reference, by Günther Theile. Furthermore, With the help of Institut für Rundfunktechnik(IRT), Stax come up with an equalizer, ED-1, which can turn SR-Λ Professional into an accurate diffuse-field simulator.

Hidition New Tears 6: New vs Old

[A big thnx goes to my dear friends, rubin, who is the owner of the older NT6, and shwl, who gladly loaned me his newer NT6. I truly appreciate them for the contribution!]

Originally started as a distributor of hearing aid brands such as Phonak and Starkey, Hidition is currently the only custom IEM manufacturer in South Korea. Unlike other CIEM companies such as Earsonics and Heir Audio, who still bang their heads against a tree stump when it comes to electroacoustic evaluation, Hidition has a capability of analyzing their own products using an equalizer, a microphone, and a simple silicone tube. It is quite disappointing though, that one of my friends, nalsse, have helped them setup the measurement jig, but Hidition never give him a credit for the contribution.

New Tears 6 is one of Hidition's top-tier models, which goes for $1,200, featuring a triple bore technology. As the internal crossover of the IEM is said to be revised once, the current model and the older model will be compared/analyzed together side by side.

Final Audio Design Heaven V Aging

Disclaimer: This review is dedicated to the owner of the IEM, Vlad. Thanks to his contribution, my review on Final Audio Design products is continuing on. And of course, Inks takes credit for organizing this loan. You never fail to impress me, my dear friend.

After the commercial success of their BAM-driven Heaven series, Final Audio Design quickly revises the lineup once again. Unlike the predecessors, which are rear-vented, the new Heaven series models are featured with an unvented design.

The working principle of the new BAM technology is briefly described in 特開２０１２－１５５８０. The possible vented/unvented schemes have been proposed here, and it can be expected that many different variations are actually available for commercialization. Interestingly, this patent is not of the manufacturer themselves, but of Molex Incorporated, suggesting some kind of partnership between two companies, or perhaps an outsourcing of the product. As 高井金盛 san, who is the representative director at Final Audio Design, has been formerly employeed at Molex Incorporated, such analogy makes sense after all.

SONY PFR-V1 part3: In-depth analysis

Disclaimer: Thanx to my friend, vAsurada, I am having another shot at this funky headphone. 

Continued from Part 2.


Sony PFR-V1 features several brilliant innovations:

1. Free-field referenced localization with separated treble / bass transduction

2. Elongated bass port (extended bass reflex duct)

3. Minimized cabinet resonance

4. High-quality materials

While considering the others as commercially driven mumbo-jumbos, the first two factors must be considered in a technical manner, since they are the fundamental working principles of PFR-V1.

SONY PFR-V1 part2: General analysis

Disclaimer: Thanx to my friend, vAsurada, I am having another shot at this funky headphone. 

Wait..

..That surely rings a bell! LOL

Paradox Audio modified T50RP by LFF

Disclaimer: This review is dedicated to Flysweep, who generously got this headphone on a loan tour for friends at Head-Fi.org. Such a great man.

The modder, LFF himself.

In September of 2011, a Head-Fi user, LFF, introduces his modified Fostex T50RP, Paradox, with a ground-breaking modification technique utilized. Once enough feedback has been gathered, he commercializes the model at his website, Paradox Audio.

In contrast to the stock version, Paradox comes with higher sound quality, which is comparable to that of more expensive headphones like Sennheiser HD650, HiFiMAN HE-500, and even LCD-2, according to Purrin. And on top of that, Paradox features an elastic headband for comfort, and a pair of sock-pads, which turns T50RP a semi-open earpad headphone. LFF hints that these pads are simply the upper part of female black socks with a pair of Fischer Audio FA-003 earpads sowed together. What a brilliant idea.

Suyama Fit Ear F111

Disclaimer #1: This opportunity has been provided by Bryan, who is a frequent contributor of this blog. Had there been no support from my fellow contributors, I would've long given up on this blog. Thank you again!

Disclaimer #2: Measurement has been carried out right at the reference plane of the occluded ear simulator, using a pair of stock single flange sleeves.

Originally named as TO GO! 111, Suyama's FitEar F111 was first introduced in July of 2012, and later released in February of 2013. As a single-BA transducer driven IEM, F111 has a lot of competitors, such as ER-4 of Etymotic Research, and SE420/e4c of Shure. And of course, in order to keep their product competitive in the game, Suyama develops a proprietary technology once again. Made in titanium, F111's テーパードポートステム(Tapered Port Stem) delivers great airiness and elegant treble, according to the manufacturer.