New reference monitor
headphones "MDR-MV1"
reproduces spatial sound of the studio.
MDR-MV1 is a new model that offers enhanced value while maintaining the essence of monitor headphones that accurately reproduce sound. By maximizing the performance of the new "360 Virtual Mixing Environment" technology, which reproduces the same acoustic environment as a production studio with headphones, we aimed to contribute to a wide range of music production sites, from spatial sound source production to stereo sound source production. The core members of the development team talk about the technology and their passion about this new model, MDR-MV1.
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New monitor headphones for spatial sound and stereo mixing
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Unique open-back acoustic structure and specially developed driver reproduces the sound created by the virtualizer with extreme accuracy.
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Even professional engineers agreed… Extreme comfort even when worn for long periods of time.
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Easy user maintenance as a tool for professional use
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MDR-MV1 opens new horizons in music creation… It has been designed to become a reference monitor for a new era.
MEMBER
Tanaka
Shiomi
Ozaki
New monitor headphones for
spatial sound and stereo mixing
First of all, please tell us what kind of product category "monitor headphones" are, that include the new MDR-MV1, and how they differ from general headphones.
Tanaka:If general headphones are intended for listeners to enjoy finished music, "monitor headphones" are for creators to check (monitor) sound in the production of music and other content. In addition to checking how the finished content reaches the listener, they are used to check whether the sound source was accurately recorded and whether the effects added to the sound source are accurately reflected.
I see. So monitor headphones' main users are creators, correct?
Tanaka:Yes. It can be said that it is a tool for accurately evaluating the work results in each step of sound production. Therefore, even if they are just monitor headphones, the required sound quality and specifications will change depending on the specific stage of production. For example, the MDR-CD900ST, which was released by Sony in 1989 and continues to be in production today, is used in the recording process for artists to check their own performances in real time and for engineers to check the sound recorded through live microphones.
In addition, the MDR-M1ST, released in 2019, inherits the DNA of the MDR-CD900ST and supports playback of high-resolution sound sources. This product is especially useful for confirming detailed sound quality and making adjustment in the recording and mixing process on the engineering side.
In addition to design features needed for different applications, the specifications required may also change with the times, such as with the introduction of high-resolution recording and playback. By the way, what is the latest situation in the music production field now?
Tanaka:There are two main changes in recent years. One is that music content itself is changing. The spread of Internet music distribution services is greatly boosting the increase in sound quality with high-resolution and immersive sound sources. The other is the change in the actual music production environment. In the past, music production was usually done in a commercial studio for professionals with a full range of equipment, but with the evolution of an integrated music production environment of a digital audio workstation (DAW), a home studio or a notebook PC is now sufficient for music production. This has greatly increased the importance of monitor headphones that allow you to accurately check the sound anywhere.
Against this background, why was a product like the "MDR-MV1" designed?
Tanaka:For example, multi-channel audio formats that reproduce a three-dimensional sound field have become common for movie content. In addition to the conventional 2-channel stereo format, object-based spatial audio formats such as Sony's "360 Reality Audio" (hereinafter referred to as "360RA") and Dolby Atmos have been spreading in severalmusic distribution services. These formats are superior to conventional stereo audio formats in terms of realism and immersion, and provide an experience as if the artist is right in front of you. However, in order to perform the mixing process appropriate for this type of spatial format with high precision, a dedicated studio environment, with multiple speakers arranged to surround the operator in all 360 degrees, is usually required. For example, 360RA requires a dedicated studio with 13 channels of speakers. The fact is that studios with a production environment that can reproduce a three-dimensional sound field in this way, however, are limited and this has been a challenge for this type of production.
Amid the need for the evolution of production environments and recording equipment accompanying the spread of spatial audio and immersive sound production, the MDR-MV1 was developed as a monitor headphone for creators that will embrace this new standard.
Is it possible to realize a three-dimensional sound production environment with the MDR-MV1's alone?
Shiomi:It is possible by combining MDR-MV1's with Sony's proprietary technology called "360 Virtual Mixing Environment (360VME)". This is a technology that "reproduces the same sound field in headphones as in speakers." By utilizing Sony's virtual sound technology and 360 degree 3D acoustic technologies such as environmental and personal HRTF optimization, the sound field of a studio acoustic space can be realized in the comfort of your own home using headphones.
Tanaka:Before COVID-19, SPE (Sony Pictures Entertainment), a film company within the Sony Group, had been facing a lack of sound mixing rooms for the production of spatial sound for film content, and a solution to this problem was sought. As a solution, they turned their attention to 360VME, which allows users to virtually listen to sound with the same quality as a sound production studio, without being restricted by location. Since then, the R&D Center, a research and development organization within the group, and SPE have collaborated to test this technology in the actual production process of movie content, and through various trials and errors, the technology has evolved. And now, in response to the spread of immersive sound technology to the music industry, we have decided to start providing services in the music field as well.
There are already various technologies for reproducing spatial sound with headphones. What are the advantages of 360VME compared to those technologies?
Tanaka:360VME is designed for professionals, so we are particular about the accuracy of reproduction. The other day, we conducted a demonstration to a group of professional engineers, but even their ears could not distinguish whether the sound was coming from headphones or the speakers.
In achieving this accuracy, a signal processing technology called "binaural processing," which is used to reproduce a three-dimensional sound field, has been greatly advanced. Specifically, the different HRTF (Head-Related Transfer Function)* of each listener is measured individually and reflected in the generated audio signal, resulting in a dramatic improvement in accuracy.
* A function that describes the transfer characteristics (how sound is heard) from the time sound reaches the left and right ears until it is transmitted to the eardrums. Applied during spatial sound reproduction, it allows for a more realistic three-dimensional sound experience.
So "MDR-MV1" is a monitor headphone for music creation that can bring out the full performance of a technology such as 360VME?
Tanaka:That's right When developing 360VME, we developed not only the signal processing technology, but also the microphones for HRTF measurement and the headphones for playback, all newly developed. We have applied this technology to the production of spatial sound sources for music content such as 360RA (360 Reality Audio), and in combination with the MDR-MV1, we offer a spatial sound source production environment that can be used anywhere. The MDR-MV1 incorporates a hardware structure that takes binaural processing into consideration, with an open-back acoustic structure that has been used since the beginning of the trial operation with SPE, and has specifications that maximize the effects of 360VME.
What kind of users are you assuming for the MDR-MV1?
Tanaka:We feel that the main users are creators of spatial sound sources for music content, but MDR-MV1's superior spatial expression and ultra-wide bandwidth reproduction capability from 5Hz to 80kHz are also suitable for mixing and mastering of 2 channel stereo sound sources including high-resolution audio. We believe that MDR-MV1's can be used by a wide range of music creators.
Unique open-back acoustic structure and
specially developed driver reproduces the sound
created by the virtualizer with extreme accuracy.
Let us delve deeper into the sound quality of MDR-MV1. First of all, please tell us what kind of high sound quality you aimed for with this product.
Shiomi:MDR-MV1 reproduces sounds created with 360VME's virtualizer technology to accurately reproduce a three-dimensional sound field, so it must have low distortion, basic characteristics that allow proper reproduction of low to high tones, and a wide dynamic range that allows proper reproduction of quiet to loud sounds.
In addition, since it is necessary to reproduce spatial reverberation and other sounds with virtualizers in spatial sound source production and reproduction, we have designed a structure that eliminates resonance on the housing side as much as possible. This structure enables stable and accurate delivery of sound to both ears after external signal processing, including sound field information.
Generally, 2-channel sound sources are mastered so that they can be heard comfortably with room reverberation during speaker playback, so monitor headphones such as MDR-M1ST have been designed to create sound with a tone balance that is close to the impression heard in the room used as a reference. However, the MDR-MV1 monitors the sound including HRTF and room reverberation information through signal processing, which is a different approach to sound quality adjustment. I think this is a major difference between the MDR-MV1 and conventional monitor headphones.
I see. Although both the MDR-MV1 and MDR-M1ST are designed for professionals, the technologies of sound production seem completely different. Can you tell us what the key structure is?
Shiomi:Sony has released several open-type headphones in the past, but this time we've adopted a new structure that we call the "open-back acoustic structure," which is different from the conventional type. In order to eliminate resonance in the housing, the rear side of the driver unit is open. In addition, the front plate has a large opening area and a tuned acoustic resistor with a certain degree of resistance to control ventilation. This technology enables reproduction from ultra-low frequencies approaching that of sealed headphones, and has been able to achieve the required wide bandwidth reproduction.
So, there was a strong reason for this structure. What difficulties did you face in developing it?
Shiomi:Developing headphones that maximize the performance of signal-processed sound was a first time experience for Sony, and we had no previous research to draw upon. Therefore, in the beginning, we had to explore everything by hand. We repeated various prototypes, including one in the early stages in which the housing of MDR-M1ST was hollowed out,while working on achieving the ideal sound.
I understand that in addition to adopting a rear-opening acoustic structure, the driver unit was also renewed in the process of creating the desired sound.
Shiomi:In order to correctly reproduce the sound field created by the virtualizer, accurate reproduction of the sound source is first and foremost required. For the MDR-MV1, we designed a new driver unit capable of reproducing high sound pressure with extremely low distortion.
Unique vibration plate with redesigned corrugation shape
What kind of innovations have been made to the driver unit?
Shiomi:Many innovations have been applied. First of all, if the front side of the driver unit has a structure that allows a certain amount of airflow, this makes it difficult to reproduce low frequencies at high sound pressure. In order to reproduce low frequencies at a high sound pressure with this structure, the diaphragm needs to be amplified and 'swung' by a large amount, but this large amplitude also results in large distortion, which degrades the reproducibility of the sound field. To solve this problem, the shape of the "corrugation" grooves on the edge of the diaphragm has been investigated. By designing the grooves to be curved instead of the usual linear shape, distortion of the diaphragm's amplitude is minimized. This shape was derived as a result of repeated simulation and prototyping, and has enabled us to achieve ideal low-frequency reproduction.
To enable high-resolution reproduction, we also repeated prototyping and redesigning of the shape of the dome in the center of the diaphragm, which is responsible for the high frequency part, to enable reproduction up to 80kHz.
So, a lot of ingenuity has been incorporated into these small, thin parts.
Shiomi:And here is the driver unit incorporating the diaphragm. The unique feature of this unit is the three tuned ducts on the back of the unit. These ducts are incorporated into the driver unit to provide beat response control, which is normally achieved through the use of ports on the housing of ordinary headphones. Another key point is that the ducts are evenly distributed in three locations along the circumferential direction of the diaphragm, which allows the piston motion of the diaphragm to be driven equally, resulting in low distortion sound quality.
Why was it necessary to incorporate the beat response control function into the driver unit?
Shiomi:Because the rear-opening structure of the housing did not allow for the installation of ducts on the housing side. There were many restrictions due to the shape of this product, so that was where we had to show our skills.
Did you have creators and engineers in the music production field try out the sound you created in this way?
Shiomi:Of course. The Sony Group has a music company, Sony Music (SME), so we brought the MDR-MV1 to actual music production sites and received a lot of feedback from people there on how they felt about using the product in the creation of both immersive and stereo sound sources and in the track creation process before that, which we incorporated into the product. This feedback is so important and is reflected in our products.
Tanaka:On one occasion, Shiomi and I traveled to the United States to try out the MDR-MV1 at Sony Music Studios in New York, and then flew to the West Coast to have movie and game sound creators try it out, as well. I think it was a good experience for us to have creators from a wide range of genres try out the MDR-MV1 in the course of their work, so that we could understand what kind of sound quality they were looking for in their sound source production workflow.
Shiomi:I was very happy to receive a comment from a famous engineer who said that "with the MDR-MV1, you can definitely make a good three-dimensional sound mix", and that comment still leaves an impression on me.
It seems that this product will be a reliable partner for engineers in the future of music production. By the way, can this product be used for music production other than sound sources such as 360RA and other spatial sound formats?
Shiomi:Yes. We are proud of the fact that this product is a tool that can be used for a wide range of purposes, including the production of general stereo sound sources. In the process of stereo mixing of music, after multi-track recording, each track is subjected to various acoustic treatments and then mixed down to two channels. This process, up to the mixdown stage, is almost the same as for object based audio such as 360RA. In fact, engineers who produce conventional stereo sound sources have praised the system, saying that they can clearly perceive the sound changes that occur during the process, and that they can work with the same sensation as in a studio (even at home).
Even professional engineers agreed…
Extreme comfort even when worn for long periods of time.
Next, please tell us about the wearability required for professional headphones. I hear that it is not unusual for people in the music production field to leave the MDR-MV1's on for 10 hours or more.
Ozaki:We designed the MDR-MV1 not only to be soft to the touch, which is immediately apparent when you put them on, but also to be comfortable even when worn for long periods of time. In addition, because the product is designed to reproduce a three-dimensional sound field, we have also taken care to enhance the stability of the product so that it can always be worn in the same position even if it is quickly picked up and put on, and also so that it will not shift position afterwards. The first step in achieving both comfort and stability is to reduce the weight of the product.
In terms of individual technologies, for example, the suede-like man-made leather used for earpads has moderate breathability and moisture permeability, making them comfortable to use for long periods of time, and its gripping property prevents shifting when worn. This fabric is also used in the seats of high-end sports cars, which require similar characteristics, which may explain the high functionality of this material.
It sounds like a material with a lot of good qualities, but why hasn't this man-made leather been used in monitor headphones up until now?
Shiomi:The material used for the earpads that cover the ears has a great influence on acoustic characteristics, so it cannot be used for all types of headphones. Also, compared to the synthetic leather material used in conventional sealed headphones, this material has modest sound insulation properties, so there is a problem with microphones picking up sound that leaks out of the headphones in a live sound recording application. We were able to use this material because the MDR-MV1 is not intended for use while recording with a microphone, but rather for mixing recorded sound or for while recording direct instruments , so we did not have to worry about sound leakage.
I see. So different applications can require different materials. So, it's a challenge in many ways.
Ozaki:Yes, and when we try to improve wearability, at some point there are conflicts that arise. One example is the dimensions of the earpads. If you widen the inner opening of the earpads, even people with large ears can use them comfortably without being cramped, but the thickness of the earpads themselves become narrower, so the pressure on the surface that touches the head increases. Also, the problem of unstable and uneven wearing position is more likely to occur.
How did you solve this problem?
Ozaki:Sony has a database of head widths, ear positions, and shapes that we have cultivated over many years, and we used it to determine the most appropriate earpad shape for this product. We also have a team in place to objectively evaluate the fit, and I feel that their ability to confirm the fit not only with data but also with human sensation has contributed greatly to improving the fit.
The first thing that surprised me, and strikes you when you pick up the product is how lightweight it is. You can't imagine how lightweight it is from its high functionality and appearance.
Ozaki:We used a lightweight and strong aluminum alloy for the housing and reduced the thickness of each part by a few percent to reduce the weight of each part in 0.1g increments. However, we did not want to make the MDR-MV1 less usable by only reducing the weight of the product. The MDR-MV1 has thick earpads for wearing comfort, but because it is a professional tool, we cannot compromise on durability and strength. It was difficult to determine where we could cut while ensuring the performance that could not be compromised, even if the weight increased slightly.
That's the kind of attention to detail that only a tool for professionals can provide, isn't it?
Ozaki:Yes, for this reason, we decided on the balance of not onlysound quality but also wearability by listening to the opinions of professionals in the field. In the end, they commented that the product "does not cause discomfort even after long use. Also, speaking of other design features, the numbers indicating the position on the slider mechanisms are a small device for ease of use, so that the user can wear the product in the same position every time without stress.
If you have any additional design features to mention, please tell us about them as well.
Ozaki:The designers wanted to use solid aluminum so that the headphones could be used for many years with their owner's appreciation, and also to clearly express the fact that they are Sony's first rear-open type monitor headphones. To achieve this, we wanted to use a one-piece aluminum housing with holes drilled all around, which was the theme we were aiming for. However, from a mechanical designer's point of view, this would be extremely difficult, so we went through a trial-and-error manufacturing process to determine what kind of holes we could drill to make it feasible. As a result, we were able to create a single aluminum housing with round holes on the top surface and many slit holes on the sides to allow the entire housing to ventilate. In terms of design, the new housing has an originality that has not been seen in the past, and the aluminum construction, with no joints on the entire surface, provides an advantage in terms of strength, resulting in a weight reduction.
Shiomi:Acoustically, the rigid aluminum construction also makes it less likely to cause resonance, and the openings are evenly distributed around the entire circumference, allowing air to escape cleanly.
Easy user maintenance as a tool
for professional use
In addition to sound quality and wearability, user maintenance is also an important factor for a professional tool. What kind of efforts have been made in the MDR-MV1 in this area?
Ozaki:First, we made the earpads easy to replace. To keep the design clean, we often use a structure where the earpads are secured by claws in a part hidden by the housing, but since earpads are frequently replaced in professional use, we needed to make them easier to remove.
It's a common method used in old headphones.
Ozaki:The cable is also detachable and replaceable, so that only the cable can be replaced in the event of a broken wire. We also adopted a screw-type locking ring structure to prevent the cable from easily coming loose, so that it can be securely fastened to the main body when installed. Incidentally, the lock ring is finely knurled to prevent it from slipping when being inserted or removed.
Tanaka:This lock ring, as well as the body of the ¼" connector is made of machined aluminum. We are quite particular about the quality of such details. We have put a lot of effort into these areas as well, so we hope you will check them out. The plug standard is a φ6.3mm stereo standard plug for connection to sound source production equipment. However, in consideration of the fact that these monitor headphones are used in a variety of environments these days, a φ3.5mm stereo mini plug conversion cable is also included as standard. We imagine you will use this cable when connecting to a notebook PC or portable music player.
MDR-MV1 opens new horizons in music creation…
It has been designed to become a reference monitor for a new era.
Finally, do you have a message for our readers?
Shiomi:This is the third pair of headphones that I have created with Ozaki. After such a long relationship, I feel that we have been able to create uncompromising products while exchanging ideas and opinions with each other. I, myself am a music lover, and in my private life, I produce music and discuss music with artists and creators. The combination of 360VME and the MDR-MV1 is one such example, and in the future, it will be possible to create music anywhere, regardless of location. I hope that this will become one of the options for sound creation going forward, and that it will have an impact not only on creators' work styles, but also on their creativity.
Ozaki:The MDR-CD900ST has been used by professionals for more than 30 years, and together with the MDR-M1ST, which inherited its DNA, it is a special model that we have strong feelings about. We felt a great deal of pressure to create a product that would rival it. However, when I look at the finished MDR-MV1 and all three models side by side, I feel that we were able to successfully create another new professional tool. I hope that many people will use them for many years to come.
Tanaka:The MDR-MV1 is the first Sony monitor headphones to use an open-type design, so we put a lot of effort into it. I hope that the MDR-MV1 will lead to an improved production environment as a new reference monitor in the era of stereophonic and immersive sound.
360VME, which I introduced as a particularly important technology, was being researched even before the production of 360 Reality Audio began. The intense experience of not being able to tell whether the sound was coming from the speakers or the headphones is still burned strongly in my mind from the demo I experienced at the time. It was a very moving experience for me to be able to combine the results of that research into the MDR-MV1 product.
Some people may feel that the MDR-MV1 is a tool for creators that makes full use of the latest technologies, such as spatial sound production, but it can also be used for creating music with stereo sound sources, and I feel that its range of applications is wider than I had expected. For example, it would be interesting to use it as a tracking monitor for an electronic piano, and we would also like music listeners who would like to listen to their favorite music with the monitor sound from an engineer's point of view, to give them a try. We hope that you will try the MDR-MV1's unique sound and fit at your favorite dealer. Thank you very much.