Page 1 (Released from restrains/Concept)
The result of having freedom to pursuit real high quality sound, birth of the outstanding Walkman
* Most people were predicting the next model to be NW-ZX3, what led to the development of the WM1 series?
Urushihara Teruhiko [Product Planning]
Although the ZX series (NW-ZX1/ZX2/ZX100) are the models which pursuit sound quality in the Walkman line up, it’s also a fact that there are restrictions during their developments. Then we start from that point of what if there is no limit in the pursuit of “making a Walkman that truly strives for the best sound”, and that became the WM1 series.
The result of having complete freedom in development to pursuit quality in both hardware and software is that the style of this model is somewhat disjointed from the ZX series and became a model that improved far more.
*So because it isn’t an extension of the ZX series, this is reflected in the “WM1 series” naming scheme.
Urushihara Teruhiko [Product Planning]
Thinking about the brand of Walkman, we really wanted to put the word “Walkman” into the model number. Although this isn’t back to basics, we really wanted to make a Walkman that is better than all the previous walkmans, and this feeling is reflected in the naming of the WM1 series.
* Please tell us more about the intention of having two models - WM1Z and the WM1A.
Urushihara Teruhiko [Product Planning]
Cutting into the chase about the circumstances, it all started from “In the end, the sound preference is different for each individual”.
For example, of course some will have to preference for “quick and sharp sound” which is the strong point of previous walkmans, on the other hard there are people who prefers “an elegant and gentle sound”. Considering that both cannot be mixed together, we developed the project with the stance that the user could “Choose the sound you like from these two models”.
*Then please tell us the positioning of the two models
Urushihara Teruhiko [Product Planning]
The positioning became clear as the project progressed during the sound tuning stage. WM1Z is able to more naturally reproduce the acoustic area compared to the WM1A so it has a wider range of expression, thus it became the top of the line model.
Sato Asaake [project leader]
Although we said just then that “the style of this model is somewhat disjointed from the ZX series”, speaking frankly without fear of any misunderstanding, the WM1A can also be said to be the proper evolution model of the ZX2. This is because it takes a lot of the same basic audio technology from the ZX2. Even then, due to the new chassis and the full digital amp, the jump is large enough that it doesn’t inherit the naming scheme of the ZX series.
*So the WM1Z is even more….
Sato Asaake [project leader]
When we push further from that point I think is how we reached the WM1Z. This is what it is like to develop without concern for things like cost, raw materials and parts. It’s almost to the point that one would question whether it is okay to go that far for sound quality, and in the end it really became a model where the brakes are off and everything was done according to the will of the engineers.
*Including the WM1 series Sony has created 3 flagship items in the “Signature Series”. Is there some common concept for sound amongst them?
Sato Asaake [project leader]
The other items are a stereo headphone (MDR-Z1R) and a headphone amp (TA-ZH1ES), and the goal which this “Signature Series” aims for is the “reproduction of micro sonic” from the moment when a performance starts till the end of complete silence. And of course the WM1 series also keeps this theme in mind during development.
Page 2 (The one and only amp/S-Master HX)
Completely renewal of “S-Master HX”. The unique heart which faithfully reproduces micro sonic.
*When it comes to sound reproduction of the WM1 series, which part evolved the most?
Sato Asaake [project leader]
The biggest point this time is that the “S-Master HX” is completely new. Sony developed inhouse a completely new full digital amp in the form of a semiconductor chip (CXD3778GF) for specially for Walkman use, and it can be said is the main reason for the big jump from the ZX series. In essences what changed is the support of balance output, DSD native (balance mode only) playback up to 11.2MHz, and Linear PCM playback up to 384kHz/32bit.
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*There seems to be some overt persistence in the full digital amp.
Sato Asaake [project leader]
We believe that there exist sounds that can only be heard with the full digital amp “S-Master”. On top of that, I think we can say with pride that Sony is the only maker which makes such a high sound quality full digital amp in portable audio. Because the unique point of “S-Master” is that it is an amp that uses no feedback, using this method even the faint sound of the input can be reproduced faithfully without being buried by the other sounds. In other words, the ability to faithfully reproduce even the faintest sound in the recording as the artist intended to convey is why we are so dedicated to the full digital amp. Sometimes we hear people say “Walkmans uses digital amp is a measure to reduce cost and reduce battery consumption”, but that is a misconception, the full digital amp of Walkman is a device that we developed via many trials and errors for the purpose of reaching the sound quality we strive for. If we are concerned about cutting cost then we would have used a general purpose amp device (laughs).
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*Is there are merit of full digital amp in balance output?
Sato Asaake [project leader]
In the world of high end portable audio, I think “dual DAC” has become the keyword when it comes to balance output. But why is there a need for dual DAC – that’s because if you use a normal analogue amp with two DACs, if you don’t physically separate the electrical signals by making separate circuits, the L channel and R channel will interfere and result in crosstalk. On the other hand, the balance output of a full digital amp cannot interfere with each other, if you let me make a bullish statement, it is in a completely different world compared to dual DACs coupled with analogue amps.
Sato Hiroaki [sound design]
In electrical circuits which use DAC and analogue amps, there are a few situations where the L channel and the R channel and other analogue signal had to be placed next to each other on the circuit board. Compare to his in the case of the full digital amp “S-Master” because the signal is digital until final output to the headphone, the chance of crosstalk occurring is reduced to the minimum.
- *Because of the renewal of “S-Master HX”, the headphone output has also increased.
Sato Asaake [project leader]
That’s right. Because we redesigned everything from the semi-conductor level up, and thanks to the evolution of the interior of the semi-conductor we successfully increased the power output. We achieved 60mW+60mW (16ohm) for unbalanced output and 250mW + 250mW (16ohm) for balanced output, so with balanced output you can drive high impedance headphones with the unit itself.
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*The balanced connection headphone jack uses the new 4.4mm standard
Sato Asaake [project leader]
Currently in the portable audio world the type of headphone jacks are all over the place… in fact there are 4 types in use right now. Recently the usage of 2.5mm has increased, but Sony’s portable amp PHA-3 uses 2 x 3.5mm. We had many very serious internal discussions of whether to continue to use 2 x 3.5mm or introduce something else.
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* What was the deciding factor in using the new standard?
Sato Asaake [project leader]
Around that time we received information that JEITA is to consolidate and propose a new standard, also one of our partner is in the processing of developing new devices based on this new standard, so we put the prototype of the 4.4mm headphone jack into a ZX2 and tested it.
The surprising result was that the transparency and the extension was changed just by changing the plug and jack, and that undeniable fact became the deciding factor. On top of that, an industry wide standard would convenience the end user as well, so we headed towards using the 4.4mm.
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*Please tell us more about the specific advantages of the 4.4mm
Ishizaki Nobuyuki [mechanical design]
Compared to the current balance compatible plugs it is mechanically stronger, on top of which because of being able to secure more sectional surface area the resistance is also reduced to the minimum. Also to prevent incidents where the small plug when pushed too far can break and parts of it would be left inside the jack, and also L-shaped plugs can be made unlike 2 x 3.5mm.
Sato Asaake [project leader]
There is one point which I want to stress here – it is that just by using the new 4.4mm standard the sound quality doesn’t improve. I touched upon this earlier – the jack that we use this time is from our partner Nippon DICS named “Pentaconn”, it’s not that the standard makes the difference, but that it is this specially developed jack that causes the difference.
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*For example, where is the difference?
Sato Asaake [project leader]
A little bit of back story, the “Pentaconn” actually has implemented a few things which we proposed as possible areas of improvements during our search for the right jacks for the ZX series. In the beginning the prototype had not implemented the requests, and during the development phase of the WM1 series when we put the jack into our prototypes, the jack itself also improved along the way.
For example, when we wanted to test the jack which is made from special copper alloy plated with gold on the outside and with a undercoating made from special non-magnetic material, Nipphon DICS will make several different prototypes for us, and Sony tests each one and then decides on the final spec.
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*Is the any other special quantities for the “Pentaconn”?
Yoshioka Katsuma [electrical design]
For the common 3.5mm connection, for each of the 3 connections (L+/R+/GND) of the plug there is only 1 point of contact in the jack. However in the “Pentaconn” each connection (L+/L-/R+/R-) there are 2 points of contact. The point of contact in the jack is made into a C shape, and both sides of the plug are in contact.
Sato Asaake [project leader]
Because there are 2 points of contact, so even if one side of the jack becomes lose the problem of bad contact would still not occur, also the decrease in surface contact resistance helps the sound quality. The design and its advantages are usually not seen in portable audio jacks where the main focus is on miniaturization.
Page 3 (Improving the sound via the chassis/Architecture I)
The forbidden oxygen free copper (OFC). The reality that stands in front of the ideal material.
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*Please tell us about the focal point of the WM1A which is milled out of solid block of aluminium
Ishizaki Nobuyuki [mechanical design]
The basic thinking is the same as the ZX2. Milling the chassis from a solid block of high purity aluminium and then putting on it a gold plated copper plate to achieve both toughness rigidity and reduce impedance, also to stablise the ground.
The improvement for this time, although it is the same for the WM1Z, is that one of the copper plate was changed from Tough-Pitch Copper (TPC) to high purity OFC. Another plate’s thickness and size was increased, both resulted in the lowering of impedance.
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*The rear panel is also the common improvement point for the WM1 series too
Ishizaki Nobuyuki [mechanical design]
That is correct. It is changed from the stainless steel of the ZX2 to a Ni-Cu-Si type alloy. Although this is the first time we use this, but because the main component of the alloy is copper it is able to maintain a high level of conductivity while also having the necessary rigidity it is an invaluable material. Compared to stainless steel the conductivity is about 20 times better, so of course the sound quality improved.
Sato Hiroaki [sound design]
Although the audio signal doesn’t go through this part, but the more we persisted the more the sound changed. This is the newest version of the “using the chassis as a ground” method that we have used since the ZX1.
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*Let’s move on to the WM1Z chassis. Please tell us about process which led to the use of OFC.
Ishizaki Nobuyuki [mechanical design]
Ever since the development of the ZX2 we have thought about trying to make the chassis out of OFC while testing out aluminium of different purity.
Sato Hiroaki [sound design]
Copper is a dense and low resistance material, if you only think about sound quality it can be said to be the ideal material. In actuality when developing the ZX1 we tested making the chasis out of brass, but because the treble didn’t sound good so we gave up on the idea. However if we didn’t stumble when trying to search for the right balance between the weight of the material and its resistance, we probably wouldn’t have looked at copper.
Ishizaki Nobuyuki [mechanical design]
For portable audio application, we had to take into consideration about things such as cost and weight, so at that time we had no plans to mass product it at all and only made it as an experiment to study the effects it had on sound. Though deep in our heart we thought it would be nice if we had a chance to make it into an actual product 3 to 4 years down the line.
Sato Hiroaki [sound design]
When actually listening to it, it is exceptionally good. Even so, when the mechanical design thought that we wouldn’t be so reckless to use OFC and assumed the prototype was going to be made using TFC I got angry and said “Of course we are using OFC!” (laughs).
Ishizaki Nobuyuki [mechanical design]
Because there are several places to source OFC in Japan, even though it’s made as a prototype, in the end we really just wanted to use the best material we got our hands on.
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*What difference does it make when using copper of different purity?
Sato Hiroaki [sound design]
From our experiment with the aluminium chassis of the ZX series, we know that the higher the purity the better effect it has on the sound quality. This is the same with other material, when the purity goes down there’s a tiny increase in the resistance, and that tiny difference has an effect on the sound.
Ishizaki Nobuyuki [mechanical design]
Even when the specification says the value is the same, and when you measure the resistance between the two there’s very little difference, I think there’s a great difference when listening.
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*So that ZX2 prototype now sees the light of the day as the OFC chassis of the WM1Z.
Sato Asaake [project leader]
Actually when we decided to go with OFC, we haven’t been able to secure a place which can mass produce it. However for us, having understood the excellent sound quality via the ZX2 prototype, we really pushed the mechanical design team to try to make it into an actual product.
Ishizaki Nobuyuki [mechanical design]
Actually during the phase of productization, there’s a new pressure which risen from the thought of whether is really suitable from the view point of mechanical design (laughs). Because copper is a material that is heavy and soft, the thought of dropping it….
Sato Asaake [project leader]
Especially regarding strength the schedule was decided in many stages, there were many tests done in the back where it felt like “If the test is cleared by this point it should be okay”.
Ishizaki Nobuyuki [mechanical design]
Structural wise it does use the frame structure of the ZX2 chassis, instead it is a very solid structure shaped like a bath tube where the entire area is increased, which is how we solved the problem of reinforcement. Also the thickness increase also helped. This is like a by-product due to balanced connection, but together with the unbalanced connection with large coils and others parts being placed on both sides of the circuit the thickness of the enclosure was increased to accommodate, which made it possible to secure the necessary strength.
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*Was it difficult to mill OFC?
Ishizaki Nobuyuki [mechanical design]
Material of high purity has increase sticky-ness to them, which means more resistance during cutting. As a result it is very difficult to cut, and the cutting blade becomes unusable very quickly. This time we had to worry about the weight too. Before cutting the OFC block weights about 1.8kg.
Sato Asaake [project leader]
Because the copper is roughly 3.1 times more heavy the aluminium, if we cut it like aluminium then the chassis becomes too heavy. If we make it lighter, then the strength wasn’t enough. Speaking from the stand point of factors to strive for in portable audio, these were difficult and completely opposite properties from the norm.
Ishizaki Nobuyuki [mechanical design]
From there we searched for the best balance between things such as how to cut it and what kind of cutting blades to use, in the end it takes 1.5 times more time to cut than aluminium.
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*What is the purpose of adding a plating of copper/tin/zinc alloy between the OFC chassis and the gold plating?
Ishizaki Nobuyuki [mechanical design]
If you directly plate gold onto copper, no matter how careful there would be tiny holes in it. For portable audio of course you would be carry it outside and touch it with your fingers, in that high moisture environment these holes will result in corrosion, that’s why there is a need to plate a primer layer in between.
Usually the primer layer is done with nickel because it looks very good, however due to the magnetism of nickel it has a negative effect on the sound, as this time put sound quality first thus we chose the copper/tin/zinc alloy due to its magnetic free property. To get a good finish with this type of plating requires very high quality of the material and the plating process and is a very difficult technique, but for the quality of the sound we didn’t give way.
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*Let’s talk about the parts used in the power supply and audio line. First the “electric double layer capacitor” in the power supply, it has increased capacity compared to the one in ZX2.
Yoshioka Katsuma [electrical design]
In was increased from 350mF to 500mF. Due to this when the power supply generates large variation waves the electric supply capability is also increased, furthermore the power supply is more stable. As the capacity is increased the charging time is also increased. As such to reach full capacity it takes roughly 220 seconds, so from the moment of powering on till that point the sound is not perfect.
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*Due to the increase, it helps in times such as when the bass hits hard
Yoshioka Katsuma [electrical design]
That’s correct. In those cases where there is a sudden large power discharge, it is able to provide a more accurate signal and thus one can really feel the difference.
Sato Hiroaki [sound design]
Not only that, but the S/N is also improved.
Yoshioka Katsuma [electrical design]
On top of that, we placed two large FET in parallel to the switch which charges the capacitor, so to have even less resistance when charging and discharging.
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*“the large battery pack”, where is there 5 cables?
Yoshioka Katsuma [electrical design]
This is developed specially for the WM1 series, we put in an extra cable each for red (+) and black (-). Because the soldering points increased it made work difficult for the mechanical design, but thanks to this the resistance was also decreased by half, power supply capacity was increased.
Ishizaki Nobuyuki [mechanical design]
It was real burden. Saying “We increased it to 5 cables” so lightly…. and usually only after it was already done (laughs).
*Was there any work put into the protection circuit board?
Yoshioka Katsuma [electrical design]
We doubled the through holes on the PCB. A through hole is a plated hole that goes from the top surface of the PCB to the bottom surface, when there is more through holes the current can flow more easily.
Sato Hiroaki [sound design]
Thanks to all these little improvements around the battery, the transparency of vocal and music instruments increased, the speed when the sound starts is also increased, I think the dedication of the mechanical design is greatly rewarded (laugh).
Page 4 (The ultimate high quality sound design/Architecture II)
Employing key parts that was the result of 3 years of dedication. Building the bridge to the desired sound
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*In the place where “OS-CON” were found in the ZX series are the “newly developed macromolecule condensers”.
Sato Hiroaki [sound design]
I really want to say this is the substitution that was made specially for the Walkman. When the development of the ZX1 was finished, we finished this part with a partner’s sound design team when co-developing a desktop amp, and when we received the prototypes we check the sound, it took 3 years of brushing it up together with that team.
The transparency and extension of vocals, power are all combined here, so till the very end we requested to make the tiniest adjustments all in the name of the best quality, it’s a part where a lot of heart is put into it.
Sato Asaake [project leader]
One of the sound we aimed for was for reproduction of natural and acoustic sound was a great match with this condenser.
Sato Hiroaki [sound design]
It really is a great match with the new “S-Master HX”, I can’t imagine not having this part.
Yoshioka Katsuma [electrical design]
In fact the number of this type of condenser used in the WM1A and the WM1Z is different. On the B side (balanced) the numbers are the same, but in the WM1A’s A side (unbalanced) several “OS-CON” is used.
Sato Hiroaki [sound design]
As the sound differs due to the chassis, and as said in the beginning of the interview the concept of the products is that the sound of the WM1Z and the WM1A shall be different, thus during the process of tuning the number of condenser differed.
(OS-CON is a registered trademark of Panasonic)
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*“Super low noise LDO Regulator”, this part is very large.
Sato Hiroaki [sound design]
It’s roughly the same size as the new “S-Master HX” chip (CXD3778GF).
Yoshioka Katsuma [electrical design]
Usually the ones used are about 1mm in size, but this time we used three 5mm ones. The cost increased significantly, but because of the excellent ability to remove noise we didn’t hesitate in using them.
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*Specifically what role do they play?
Yoshioka Katsuma [electrical design]
For example when you need 5 volts of electricity, first you must get about 7 volts from the battery and in switched-mode power supply. After that the regulatory removes the noise and reduce it to 5 volts.
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*So in other words it purifies the power?
Yoshioka Katsuma [electrical design]
That’s correct. We deliberately increase the voltage from 4 volts to 7 volts, then aim to decrease it to 5 volts and during the process remove the noise from the switched-mode power supply as well. When the number of times voltage change is increased it uses up electricity and has some impact on the battery life, but we prioritised the sound quality first.
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*The “large coil” used in the balance output LC filter, what effect does it have on the sound?
Sato Hiroaki [sound design]
From the 7mm size of the ZX2 we increased the gauge of the coil wire so it became even bigger. Because of this there is an increase in power output and the resolution for the entire frequency range is increased.
Sato Asaake [project leader]
Not only it is the case for this coil, but also the previously mentioned headphone jack and condenser too, they are all parts that were made since the ZX series with great help from our parts partner. Although we can’t say they are just for Walkman use, but thanks to them there’s an increase of parts for us to strive for sound quality in the walkmans.
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*For the muting circuit of the balance output there are two “relays” with great presence
Sato Hiroaki [sound design]
It’s a mechanical relay that is opened with magnets when muting sound, and when sound is played it is shut with a click.
Yoshioka Katsuma [electrical design]
It’s a switch to prevent noises from being transmitted into the ear at times such as when power is switched on, it’s controlled by software and is triggered frequently.
Sato Hiroaki [sound design]
Previously we use larger than usual transistors for this purpose, but in listening the sound quality difference was vast. It’s large and close in size to the one used in PHA-3 and again caused trouble for the mechanical design, but in prioritising the sound quality of the balance output we pushed for its usage.
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*What’s the purpose of using “large high sound quality resistors” in the WM1Z?
This is a part that is used in desktop home audio products, and during development I listened to it and really wanted to use them in the WM1Z. They use non-magnetic copper plating so the sound is very faithful. The WM1Z’s soft, extended and glittery sound came out exactly as intended.
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*The 2 clocks (48kHz/44.1kHz) also both increased in size
Yoshioka Katsuma [electrical design]
Previously the size was 3.2mm by 2.5mm, this time it is increased to 5.0mm by 3.2mm. Inside this chip is a crystal and IC, but due to the increase in space it became possible to make a layout such that it is difficult to be affected by IC noise, thus resulting in an oscillator with lower phase noise. Also the oscillation frequency is doubled to match the new “S-Master HX”.
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*The audio block and digital block is cleanly separated
Yoshioka Katsuma [electrical design]
To prevent effects from digital noise from things such as the CPU and memory, the audio block is placed at the top and digital block is placed at the bottom, on top of which the unbalance (A side) and balance circuit (B side) is also separated completely by placing them on different side of the board.
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*It is said that analogue output is removed
Yoshioka Katsuma [electrical design]
Analogue line out/line in no longer goes through the WM-Port. If we are passing an analogue signal then the digital block must contain a ground for analogue use, and because this influences the sound quality so we removed it completely this time.
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*The WM1Z uses cables internally that was co-developed with Kimber Kable
Sato Asaake [project leader]
When Sony collaborated with Kimber Kable to develop headphone cables, a Braid cable of size that could be used as internal wiring for Walkman was also developed, so for the WM1Z we used them for both the balanced and unbalanced output.
By this, from the amp to the headphone jack, and if you connect the headphone cable which is sold separately, then the entire length of the circuit all the way to the ear are Braid cables.
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*What effect does this cable have on the sound of the WM1Z?
Sato Asaake [project leader]
The characteristics of sound with Braid structure that is unique to “Engineered with KIMBER KABLE” cables couples exceptionally well with the WM1Z. For example, since the impedance is flat all the way up to high frequency range, the merit is that it can reproduce very good reverbs and reverberation sounds.
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*What is the reaction of Kimber Kable?
Urushihara Teruhiko [Product Planning]
When I went to America and showed them the internals and let them listen to the sound, the people of Kimber Kable was very pleased with the cables making way into the player itself.
Sato Asaake [project leader]
I went as well, and everyone was excited with comments such as “The sound quality is amazing!” and “You really went for it!”, even the floor shook a little.
Page 5 (Breakthrough UI/Software)
The UI is pictured from the image of listening in the room. “seeing the sound” and “analogue feel” were also big themes
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*The software also changed drastically. Please tell us the concept for this time
Harada Kazu [software design]
Up until now the walkmans had 2 software platforms - “A series type” and “Android type”, but as said in the beginning during the product planning, this time software design was also made with no constraints and lots of freedom. The first thing that was decided was the framework of the UI. As you know there are various functions in a Walkman, and after many discussions with everyone on how to provide these functions to the customer and what type of experience they should have, the concept of “making the playback screen the main screen” was born.
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*So you put the playback screen in the centre, and put everything else around it?
Harada Kazu [software design]
Again, unlike previous Walkman there is no need to go back to the Home screen, the Playback screen is main screen and is placed in the centre. The is the major premise.
From there, when I try to picture what situation I would be experiencing this Playback screen, the image of “sitting on the sofa in the room listening to music” appeared in my mind.
Next is picturing the situation of choosing the content. Although it’s rare now, “picking a CD from the rack”, the image of getting up from the sofa to get a CD was the image, and so “Library Top” was placed above.
Then, what sort of situation would customizing the sound be like. Here there’s no movement and the image of “controlling in the hand” is why “sound setting” is placed below.
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*So the top and bottom screen is decided, how about left and right?
This time is to picture the situation of checking the track list of the album currently in play. Here I image it like “taking a glimpse of the CD case” so the “Playlist” is placed on the left side.
Then, I thought about what should be placed on the right side, when thinking about that I remembered old mini component systems where I could program my own playlist, the situation is like “putting your favourite item on the side table”, so I made the right side the “Bookmark List”.
In summary, there is a sofa in the middle “Playback screen”, above that is the CD rack “Library Top”, below is the panel which controls the machine “Sound Settings”, the CD case “Play List” and the side table “Bookmark List” is on both sides within reach of the hands, that’s the image I pictured and put into the UI.
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*There’re now 5 modes for “DSEE HX” which up samples normal music to hi-resolution
Sato Hiroaki [sound design]
This is something our team requested from the software team. You can choose from standard/female vocal/male vocal/percussion/strings, for example “female vocal” makes the treble extension more sparkly.
Previously “DSEE HX” was positioned for compressed sources, but when applied to CD sources it really makes them sound like a hi-res, so we really hope users would try and use these modes.
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*It’s happy to be able to see that improvement.
Harada Kazu [software design]
We added a spectrum analyser similar to old components with a graphic equalizer. When you turn on “DSEE HX” and change the “Playback screen”, on the right side of the spectrum analyser is a part labelled “High” where you can see the effects. Also we added an analogue level meter that is like the VU meters on amps, “visualizing the sound” is a theme this time, and being able to see music with eyes is something new which we persisted in the UI.
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*The equalizer was also improved.
Harada Kazu [software design]
We increased it from 5 bands to 10 bands (31Hz~16000Hz). This time each band covers exactly one octave, and with 20 steps (-10.0~+10.0) with each step of making 0.5dB adjustments, we think the users can make settings that is even closer to their taste.
Sato Hiroaki [sound design]
It’s also worth noting that by making upward and downward adjustment on the slide, the graph is now displayed as a curve too.
- *What sort of function does the “DC phase linearizer” perform?
Sato Hiroaki [sound design]
This feature is something that we have looked into since 3 years ago, and we were finally able to put it in this time. Basically, it is to make the low range phase behave more like traditional amps.
As for why is this feature needed, it is because Walkman’s full digital amp “S-Master HX” (CXD3778GF) does not have a coupling condenser like traditional analogue amps.
The coupling condenser is a part to cut off DC components and very low frequency signals, but it also affects the phase of low frequencies. Depending on the content the presences of a coupling condenser makes a difference, in other words the difference is felt in the phase difference in the low range, and this is the effect when using the “DC phase linearizer”.
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*So is it something that is instantly noticeable when engaged?
Sato Hiroaki [sound design]
It’s not a difference that would floor you, but when something that works well with “DC phase linearizer” it will make you think “Oh that’s right, that’s the bass punch I wanted.”, and once you get used to it it will surprise you. Also there are 6 different phase modes (A/B pattern x High/Standard/Low) to choose from. Please try them out.
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*There’s a significant increase in the volume adjustment steps
Harada Kazu [software design]
We doubled it from the ZX2 and it is now 120 steps. Furthermore you can now set the gain (Normal/High), so changing the gain depending on the headphone and earphones being used will now make it even easier to finely adjust the volume.
- * It seems that “Analogue feel” is the keyword for the software this time
Harada Kazu [software design]
That is true. I had a strong desire to represent the worldview of audio equipment from the past. For example just now we were discussing the experience of the volume changing knob for one. When you touch the volume bar at the top of the Playback screen it will show the volume changing knob, if you touch it with your fingers you can change the volume. We also prepared a tone control knob interface as well.
Page 6 (Inevitable design/ design)
The design that directly accept the story of “making sound”
* What concept do you have when designing the WM1 series which strives for the ultimate sound quality?
Tanaka Souichi [design]
Because every is “about the sound”, there is absolutely nothing about the WM1 series which prioritised the design over the other aspects. We started working together since the early phases of development and how the sound would be made was shared with us, so in directly reflecting the design team’s thinking the resulted in this shape. In essence, the story which the engineers told in this interview is the design concept.
* The protruding sides for the headphone jacks attracts attention.
Tanaka Souichi [design]
For the WM1 series, the circuit was designed such that the signal flows straight from the memory in the base of the unit to the headphone output, so the headphone jack was placed right at the top. However, due to this the space to for the antenna at the top is reduced and that became an issue. One proposal was to make space by extending the top by 20mm, but the added vertical length would have many effects such as pushing the touch panel downwards thus making operation more difficult, so we decided on the plan to just make the headphone jack part wider horizontally.
* So the iconic protrusion of the WM1 series wasn’t a decision based on styling.
Tanaka Souichi [design]
As with the protrusion on the back for the ZX series, it is a design that follows from prioritising the sound, but resulted in an iconic characteristic. However, the cut out between the jack and the control section was added for ergonomic reasons.
* There are various curves on the edge, what was the intention for those?
Tanaka Souichi [design]
During the designing stage, there was a request from Mechanical Design "to eliminate the angular part of the edge" in order to prevent abrasion etc. due to aging.
As already mentioned the WM 1 series chassis is cut out from a block of metal, we want to make sure that beautiful process is directly reflected in the ridgeline, else it will look like a injection molded case rather than milled chassis. However if it is made to a right angle edge, it becomes easily dented with impact and has an uncomfortable feeling in the hand…
The solution to the dilemma is to round out all the edges first, then cut the rounded edge partially at the middle. With this process it leaves a beautiful edge with a surface configuration that makes the angle equivalent to 130 degrees, it’s a finish that is easy to hold and not easily scratched.
* Where they any special effort that went into the hardware buttons?
Tanaka Souichi [design]
Due to the weight of the WM1 series when dropped it will suffer a great impact, as such the buttons were made flat and non-protruding, and for easy pressing the sizes were made big. Also in total there are 3 places with small bumps on them such as the “Play/Stop” button such that when in the bag or the pocket it is still easy to control without hesitation.
On top of which, the most used buttons – “Play/Stop”, “Vol+”, “Vol-“ – has counterbore added to the surrounding. The indention makes a contrast to the flat surface which makes it easier to distinguish.
* The separately sold case this time opens vertically
Tanaka Souichi [design]
With the hardware buttons and the headphone jack layout the number of times you have to open it increases, so this styling is inevitable.
As we were talking about details, we were able to secure two recess points just under the strap hole and the finger hook of the microSD memory card slot, so this time we successfully made a case which can open fully without exposing the back.
* What do you mean by that?
Tanaka Souichi [design]
Working in this job for a long time it’s an issue which comes up often – it is that conflict happens frequently between development members when securing space. And the request for designing an optional accessory such as a carrying case comes at the end of development, which is at the point where "oh it’s already too late", it’s impossible to have 100% freedom to consider the assembly method ... I’ve backed myself into a corner many times (laugh).
Fortunately, for WM 1 series I was participating since before the final construction decision, I thought that "If I don’t secure recess points to hook the case immediately it’s going to be bad", that's why I immediately made my request to the mechanical design team.
Mechanical design is under pressure from both electrical designer and designer and gets sandwiched in between, and I feel sorry for them as they don’t have much freedom to move too, however if I hear "there’s enough space" and let my guard down that space would be filled 3 days later, so this time I strongly forced my request (laughs).
* What about the separately sold remote?
Tanaka Souichi [design]
Since this remote also supports the new A series, so as to make the overall style coherent as well as to increase the rigidity the design was a overall very flat with sides a slightly rounded. In addition, transparent material is cut into shape of the main body and is applied with a paint that is mixed with a bead material, resulting in a slight moist finish that is great to touch.
I expected that there will be many customers who will use it by attaching the remote to the headphone cable, so I bundled two kinds of attachments that corresponds to cables of various thickness. Of course, you can also keep it in a pocket like a clip too.
Urushihara Teruhiko [Product Planning]
Also because the WM1 series is heavier than the ZX series is also one of the reason for making the remote. Besides having it in the pocket, we think there will be many who will be walking with it in a bag, and in such circumstances having a remote will definitely add to the convenience.
* It’s true that it’s not as easy to carry like the NW-ZX100
Sato Asaake [project leader]
That is true. Especially WM1Z’s OFC chassis is of considerable weight at about 455 g... but I can say with confidence the Walkman can be used alone without going through a portable headphone amplifier is a big advantage.
Although it is certainly heavy, the height is smaller by much as 7 mm compared to the ZX2, and previously for high impedance headphones the need for a portable amp is no longer necessary with the unit being able drive them alone, the battery life is definitely long, and with only one L-shaped cable the package I think is very attractive. Of course, portable amp has its own advantages too, so it’s not a simple comparison. But being able to achieve this level of quality in a single package .... including the ability to experience the sound of a balance connection is step above the world of the ZX2, and I think that is a big breakthrough for us.
* Finally, a message for all the users
Urushihara Teruhiko [Product Planning]
To summarise the comments made by the development members, I think it is that "everything is all connected to sound". Both the chassis design and the parts in the audio circuit are of the highest sound quality technologies that Sony has at this moment, and everything combined into a portable audio package becomes the WM1 series. I can confidently recommend this to everyone. Please look forward to the release.
Sato Asaake [project leader]
From the ZX1 to the ZX2, and now the WM1 I have been the project leader of Walkman's flagship model, but this time I am proud to say that the two models are a big jump from the ZX series.
Through development of the ZX series, our engineers gained experience, and places where it weren’t perfect, or this part isn’t as good as the other in the ZX2... those places we have all overcame this time. In that sense, I think the WM 1 series as a portable audio device has finally reached one point of arrival.
Due to that the cost is differently not cheap, especially WM1Z with a 300,000yen price may be viewed as a bit unusual, but we packed in all the sound technology we possess with no regard of cost. The level that you can experience when you listen to it is dramatically above that of the ZX2, so I please experience this sound yourself.
Yoshioka Katsuma [electrical design]
Using the new "S - Master HX" we were able to make two models that leaped over the ZX series. Although I already talked a lot in this interview, there are still parts that I think I haven’t fully communicated yet, so I would like you to actually pick it up and touch it yourself. Surely, the greatness will be conveyed at that moment.
Also, since I was in charge of an optional remote control, I would be pleased if you could use them together, and hope you would be satisfied with the convenient and comfort of use.
Ishizaki Nobuyuki [mechanical design]
Leveraging the experiences we accumulated in the development of the ZX series, we further challenged ourselves this time by increasing the purity of the material of the housing and quality of the parts, and the result is the WM1 series. Both in the case of the OFC of the WM1Zr and the aluminium of the WM1A, the high purity material is directly reflected in the sound, I'd wish you to feel the close connection between the chassis and the sound quality.
Harada Kazu [software design]
For the WM 1 series, even the software was built from scratch. In particular I am persistent regarding the theme of "visualization of sound", and equipped the UI with things such as spectrum analyser and analogue level meter, so please not only listen but also enjoy it with your eyes.
Regarding the operation aspect, previous Walkman user may feel a bit of confusion at first. However, if you get used to it, you should feel that this one is easier to use. If you find a demo unit at the shop front please try out its touch operation, and if you like it, there is no higher pleasure speaking as an engineer.
Tanaka Souichi [design]
The moment I borrowed a demo unit to listen to the sound, I was really surprised - "this is amazing!” I thought. Even the songs that I've listened to so many times before, it was the first time I heard singer entering too much feeling into his vibrato and he quivered a bit .... It is not only a good sound, but it’s a sound quality that conveys the feelings of the singers and the musicians, that’s the WM1 series.
Speaking also as a creator, I realise again that it is a very good thing that the feelings put in the work or the product are conveyed so firmly to the recipient. I think the customers will be able to experience such a moment while listening to his or her favourite artist's songs, and that is exactly the feeling we put in this Walkman.
. The body chassis is made of pure OFC copper solid carving, and 24k Gold plated with Matte finish, which put the 1Z gold color to be Deeper and Darker in tone. This unique chassis casing is used for the return and grounding purposes as the engineers had disclosed. The conductivity of Copper is great and that it reduced the resistance, provided better signal integrity for the ground, and because it is so pure, the signal integrity stays the purest when compare to Aluminum version on 1A . That is not all the tricks.
. It is similar to the boxing of Zx2. The experiences is not as special as opening headphones MDR-Z1R for sure.
