A Short Introduction
Earlier last weekend, I had the chance to come together with the Sony Singapore team for a second time since IFA at the Singapore Sony Signature Series event. I had a great time meeting many members of the SG Head-Fi community in person, and spent some time re-auditioning the Sony Signature lineup. Present at this event was Chief Sound Architect Koji Nageno, who really helped answer some of the questions that the community had regarding the MDR-Z1R. I intend for this piece to be more of an informational write-up, but I do suppose it is rather impossible to avoid sound impressions, so I’ve included some additional thoughts below.
Shift Of Perspective – Focusing In On Design
I started my little Q&A with a clarification on the development of the MDR-Z1R. There have been so many questions regarding whether the headphone is just an upgraded version of the MDR-Z7 (and why it has such a high price tag) that I simply couldn’t afford to leave it unanswered. Nageno-San’s explanation was thoroughly informative, and really changed my understanding of the Z1R. Simply put, we can’t understand the MDR-Z1R’s development without first examining the deeply intertwined development of the Sony 70mm driver. Yes, these are amongst the largest dynamic drivers (if not the largest) currently employed in the headphone market. Work on this concept began in 2010 while Sony was developing the drive unit for the MDR-XB1000. The end result was a generally well-received bass oriented headphone. Over the years, it has gained something of a small cult following. While the PET XB1000 70mm driver design wasn’t particularly refined, Sony obviously saw potential in its design. This led to the 2014 release of the MDR-Z7, which witnessed the introduction of the updated aluminum-coated LCP 70mm driver. In similar fashion, experiences with the MDR-Z7 then led to development of the Z1R driver. Initially, I kept pressing to figure out if the Z1R driver was just an upgraded version of the Z7’s, but here’s what I came to realize from Nageno-San. The true focus has actually been in perfecting the implementation of the 70mm concept. Yes, it is the size of the driver that is the underlying theme here . Aluminum-coated LCP, magnesium dome, etc. should be viewed as the technological aspects that have made the implementation of a successful 70mm driver possible.
So why aluminum-coated LCP? According to Nageno-San, there are two primary concerns to be had when picking a material for the driver. Acoustic velocity and internal loss. The ideal material should seek to strike a balance between these two elements. Acoustic velocity is the rate at which a disturbance travels through a medium, and internal loss factors contribute to the resonant ringing in drivers. For example, low internal loss means that drivers will continue to ring even after an input signal has stopped. Effectively, the resonant characteristics of the driver start to come through and this is unfavorable in most scenarios. I took a look at an analysis of several driver materials (including Beryllium) with Nageno-San, and unsurprisingly the top choices came out to be aluminum-coated LCP and biocellulose. And about the biocellulose? Originally, the Ajinomoto Company had developed (and rather unsuccessfully applied) biocellulose technology to packaging applications. Through Japan’s Agency for Industrial Science and Technology, Sony was introduced to Ajinomoto’s efforts in biocellulose development, and with the help of some other companies Sony was able to harness biocellulose technology for use in acoustic diaphragms. Somewhere along the line, production seemed to have stopped with Ajinomoto. Digging through Japanese patent records, I found that Ajinomoto had the patents on the cellulose-producing bacteria, while Sony and the AIST had jointly patented the acoustic applications of biocellulose. Interesting!
The New Kid In Town?
Naturally, I went in for the big question. Is this headphone better than the R10? The answer is, technologically – yes. There you have it! The answer isn’t quite so straightforward…or is it? Anyways, I was quickly reminded that each Sony flagship was a reflection of their designer’s personal tastes, and in this case the Z1R was Shunsuke Shiomi’s masterpiece. In many ways, it is deserving of this title. There are a great number of technologies in the new Z1R that you won’t find mentioned on the product page. It’ll also help to explain the cost of the Z1R. To start, let’s examine the driver unit. The new magnesium dome piece comes in at a mere 30 micrometers, and cannot be manufactured via a conventional press. I’ve been told that I cannot share how Sony managed to achieve this, but I can tell you it’s pretty ingenious and all in all rather impressive! The benefits are noticeable –the magnesium dome driver allows the Z1R to achieve better high frequency performance, and the LCP complement allows for more flexibility at the leading edges.
Some may notice that the magnet is comprised of two pieces as well. Let’s go over a quick rundown of what’s going on. To produce a magnet, and in the Z1R’s case, a neodymium magnet, several fairly standard processes need to take place. First a mixture of elements (including the central Nd2Fe14B) need to be melted in a furnace to produce an alloy. This alloy is then milled down into fine particles, which are pressed at higher temperatures to form a solid. The following gets a little tricky, and I didn’t get all of it on Nageno San’s first pass. In fact, I took what he told me and did a little additional research -and here’s how I can best explain it. There’s two standard ways of pressing – both involve an external magnetic field. The first is a transverse press. According to Nageno-San, this is how Sony has been making magnets in the past. Essentially, you compress the magnet while running a magnetic field perpendicular to the direction of the press. This tends to result in better magnetic properties for Neodymium magnets. Unfortunately, it also means that the preferred direction of magnetization is on the horizontal axis. The other method is the axial press, where the magnetic field is applied parallel to the press, resulting in a direction of magnetization along the vertical axis. To work around this, the Z1R driver has been cut into two pieces, and instead of pressing onto a flat, horizontal ring-mold, the mold has been flipped on its side. A transverse press still results in a preferred direction of magnetization on the horizontal axis. However, since the ring was on its side, when placed flat this direction is now on the vertical axis of the magnet! This anisotropic magnet is sintered to shrink pores within the mixture, machined, and magnetized via a huge electromagnet. Two of these half circles then come together to form a single, stronger, magnet.
A large amount of effort has also been put into the housing of the MDR-Z1R. The new acoustic filter enclosure allows for the same net venting as the MDR-Z7, albeit with more uniformity and across a larger surface area. I couldn’t help but to bring up the Fibonacci filter in the process – it certainly looks nice but what exactly does it do? Nageno-san explained that the frequently seen ring baffles tended to create reflections at certain frequencies, and the resulting peaks and troughs were sonically detrimental. The idea with the Fibonacci grill was then to disperse these reflections in a semi-random manner across the baffle. Thinner arms and harder, higher quality plastic for the baffle also contributed significantly. I find it a curious approach – instead of tackling the reflections directly, it’s a tradeoff that results in slightly more reflections in different places, but overall lowering the more jarring immediate effects of larger, more isolated reflections.
And about the 120K extension? There were several compelling, but still unproven theories posed by Nageno-San. However, most of us agreed that while scientific proof has not yet been produced, it was indeed possible for supposedly inaudible frequencies to affect our perception of sound. The 120K extension can then be seen as the ultimate safety measure. It certainly couldn’t hurt at any rate.
So how does all of this sound? Well, I’m still impressed by the Z1R on my second listen – and my original impressions remain mostly unchanged. I will say that the bass does have presence, and I definitely have to investigate further once I receive my review unit. I will also mention that the isolation is excellent on this can – but that it does get a little warm after a while (though this could also just be the number of people in the room at the time). I will not provide more impressions on the DAPs until I can volume match and test them in a quiet environment. It’s all too easy to go wrong with DAP testing, especially in noisy show conditions. I also had a chance to play with the amp a little more, and noticed some changes after turning off the DSEE HX and DSD upsampling functions. Overall, I came away with some very positive impressions, and I really look forward to giving the Signature Series an in-depth look in the coming weeks.