Enjoy your content. Anywhere, Anytime.
『HT-AX7』 Portable Theatre System.

Content-based audio-visual experience is undergoing a dramatic change following the proliferation of smart devices and growth of internet streaming services. In this context, Sony has announced the HT-AX7 portable theatre system, offering an unprecedented new audio-visual experience. The core members behind the development of the HT-AX7 discuss new ways and experiences demanded in today's world of multi-device entertainment.

  1. Overview
  2. Mechanism and design
  3. Product quality
  4. Ease of use
  5. Environmental consideration
  6. Summary


Product Planner
Project Leader
Sound Director
Design Director

HT-AX7. A revolutionary home theatre that enables
spatial sound enjoyment anywhere in the home.


Firstly, can you tell us about the evolving style of content appreciation these days?

Chijiiwa: A typical content appreciation in the past was enjoying movies and TV programmes with the whole family on a large TV set in the living room. Recently, however, with the proliferation of personal devices such as smartphones and tablets, and the diversification of content via popular video streaming services, content enjoyment is no longer restricted by time and place.

An increasing number of young people do not own a TV. HT-AX7 is a completely new form of home theatre system. Can you explain what this product is?

Osawa: The ways of listening to and watching content has diversified. A conventional home theatre system is restrictive in that it is usually connected to a TV set-up in a living room. We developed the HT-AX7 to do away with such a restriction, allowing anyone to easily enjoy the spatial sound of the latest home theatre equipment using any device at anywhere they like. The main unit has two built-in front speakers, with detachable rear speakers for you to place anywhere towards the rear to surround you in a 360-degree acoustic space.

Chijiiwa: The catch is the wireless connection between the image-projecting device like a smartphone or tablet and the three speakers. The speakers have built-in batteries, so no power cable is required. The small and light-weight unit makes it easy to carry around for installation even in the smallest space possible, be it your desk or your bed.

So you have created a new design that eliminates the use of cables as it is completely wireless, compact and can be used anywhere.

Chijiiwa: That's right. The batteries last for about 30 hours each, so you can enjoy a movie every day for up to a week. The rear speakers can be kept on top of the front speakers when not in use and will charge automatically.

Osawa: The small unit size may lead you to believe that the experience will not be great. But, you can position the HT-AX7 speakers closer to you than most home theatre system, allowing you to enjoy superbly realistic surround sound in movies and music.

Chijiiwa: Besides allowing one person or a small group of people to enjoy movies and live music using Sony’s proprietary 360 Spatial Sound Mapping technology, another sound mode is available for filling an entire room with sound so that even a large group of people can enjoy the music. You can simply switch the mode to suit the location, content, and ambience in which you are listening.

What kind of user profile do you envisage for HT-AX7?

Chijiiwa: So far, spatial sound could only be enjoyed in front of the TV in the living room. 3D headphones are becoming popular in recent years, but they too are meant for personal use. With the HT-AX7, you can enjoy spatial sound anywhere at home, and it does not block out ambience sounds like headphones do. People who want to enjoy content with better sound production without being restricted by location, device, or use case now has a choice. Please give it a try.


Entirely new way of experiencing sound. Freedom like never before.


The HT-AX7 is a new product, and there are many questions I would like to ask you, but first of all, please tell me about its unique mechanism and design, and how it was conceived.

Osawa: The configuration for producing spatial sound requires one front speaker and two rear speakers. We began by looking into the shape and considering how we could make it easier for customers to use casually. In terms of portability, we initially got a hint from a picnic basket with handles. We thought that if the two small rear speakers could be placed on the large front speaker, it would not only facilitate charging the rear speakers but also carry them around.

While working out actual use cases, we found that, for example, when a laptop was placed behind the front speaker, the handles would often interfere with the viewing experience and, if the handles were foldable, they might not be sturdy. We tweaked our approach and solved these issues by doing away with handles and had finger indentations on the bottom of the front speakers instead. The layout of placing the rear speakers on the front speaker remained as it was in the beginning as it was a usable and simpler design.

What is the reason for having thin cylindrical shape for the two rear speakers?

Miura: To realise the concept of HT-AX7, we considered rear speakers in a variety of shapes, but small speakers in a typical box shape would fall over or tilt when placed on a sofa or bed, making it difficult to stabilise them. In this respect, we thought a circular, thin shape with the speaker facing upwards would be a logical shape to meet our objective.

Now that we have seen the merit of a shape, what is merit of having the speakers facing upwards?

Miura: It means that sound is no longer directional. Surround speakers in conventional home theatre systems are placed in specific locations where the sound field is optimised to create an acoustic space. However, with HT-AX7 which can be carried around to different rooms, we wanted to have the freedom to enjoy spatial sound immediately anywhere. Moreover, the location of the rear speakers can change each time, so we wanted to ensure that the sound would not change significantly no matter how the speakers were placed or where they were facing.

At first glance, the furnished texture of the unit does not make it look like an audio equipment. What are your thoughts on this?


Osawa: To align with the product concept, we wanted to give it a soft texture that would fit naturally into a variety of interiors. We decided to use fabric to envelope the entire unit as it would not feel out of place on sofas and beds. In doing so, we had to ensure that the seams of the fabric were not visible.

The bottom and top surfaces, which are not covered with fabric, are also made of silicone material, so that it feels soft to touch and silent when placed on a hard surface.

If the texture is important, so is the colour. Am I correct?

Osawa: Besides the texture, we were focused on ensuring that it blended in homes, so we tried various neutral greys that were neither too light nor too dark and decided on this colour.

What other design aspects have you focused on?

Osawa: In the HT-AX7, the cylindrical rear speakers are placed on the top surface of the front speakers to charge. The shape of the charging terminal has been devised so that users can charge the rear speakers no matter how they are rotated and placed. By making the contacts on the rear speaker side circular, it can be connected to the front speaker’s contacts in any orientation.

What a unique idea!


Osawa: With speaker orientation no longer a factor thanks to cylindrical rear speakers and no visible seams on the fabric, we enabled the user to simply place and charge the rear speakers.

Chijiiwa: It can be a hassle should you need to orientate the rear speakers to charge them each time. With the HT-AX7, our aim was to eliminate the inconveniences that come with each use, so you need not worry about how they should face. Simply place them down to charge them.

Itagaki: As the front and rear speakers are held in place by magnets, they are unlikely to be dislodged when shaken or tilted slightly while being carried around.


The focus of HT-AX7’s sound production is enjoyment.


Now tell us about the sound quality and sound experience of HT-AX7. First, how did you approach the sound production?

Miura: As I mentioned earlier, this product focuses on easy and simple of delivery spatial sound for any user to enjoy. To reproduce an accurate sound field for spatial sound experience, the shape of the room and the position of the speakers must be measured properly. However, with HT-AX7, you can fully enjoy spatial sound without having to make any measurements.

I see. So that's the sound production approach for this product.

Miura: Yes, I have worked on several professional and home audio products that pursue precise sound quality, but with HT-AX7, I put emphasis on 'enjoyment' than 'precision'.


Please tell us a bit more about the mechanisms that create such 'enjoyment'?

Miura: The HT-AX7 surrounds the user with three speakers to form a triangle, creating a 'sound field' within which the user can enjoy a spatial sound. This is the basic style of use for this unit.

Chijiiwa: In this state, you can easily enjoy spatial sound without the need for troublesome settings. For example, you can use it when watching movies on a tablet on the bed, watching online live shows on a smartphone while sitting on the sofa, or watching YouTube videos on a laptop at the desk.

Miura: There is also another mode available, where the sound field is turned off and the three speakers are positioned in the corners of the room, to create room-filling sound like in a cafe.

Chijiiwa: Although it is different from spatial sound, it provides an enjoyable experience by uniformly filling the room with sound. The system is designed for use whether you are relaxing or concentrating, with your favourite music left playing in the background. It can also be used in large living rooms of up to about 40 square metres, for home parties and so forth.

The ability to switch between 'sound field' on and off - two different sound experiences - seems to be a feature of the HT-AX7. Please tell us how you create an acoustic space with the sound field turned on. You said that the three speakers are arranged in a triangular shape, but how exactly do you set them up?

Chijiiwa: To enjoy spatial sound with the sound field switched on, place the front speakers in front and the rear speakers behind at 1-1.2 m away from the user in the centre, to form a triangle. The number of people who can enjoy music in this mode is therefore assumed to be one or two.

Miura: The spatial sound field is generated using Sony's unique 360 Spatial Sound Mapping technology, or 360SSM in short, which creates virtual speakers (phantom speakers) arranged in a dome shape to make the sound feel multi-dimensional. The stereo audio sound source is transmitted from a smartphone or tablet, and converted into spatial sound by Sony's unique up-mix technology. This means that any source can be enjoyed in spatial sound.

Is it OK not to carry out measurement or optimisation?

Miura: It's OK. Based on the HT-AX7 concept, I tried out different patterns, and found that the tolerance of the 360SSM is higher than I expected, and in situations where each speaker is placed within arm's reach, you can feel that the spatial sound field is sufficient.

I took the opportunity to experience the HT-AX7 prior to this interview and was surprised that the sound was firm and multi-dimensional, even when the rear speakers were randomly placed. Are there any other innovations unique to this product in terms of generating the spatial sound field?

Miura: Since the emphasis of this product is on 'enjoyment', its spatial sound field has also been tuned for that purpose. Specifically, the position of each virtual speaker, the strength of the sound and the timing at which the sound is produced have been finely tuned. As a result, it is easier to get a clear sense of spatial sound, and I think we have succeeded in creating a surprising experience for people who have never heard spatial sound before.

The impact is indeed phenomenal. I would like people to try it, especially if they have not experienced spatial sound before. Next, please tell us about an alternative way of enjoying the sound field when it is turned off.

Chijiiwa: The most important difference between sound field off and on is the placement of speakers. With sound field off, you can place the speakers anywhere as long as they surround the entire room. They do not have to be positioned triangularly or at the same height.

Miura: In this mode, the front speakers resonate music throughout the room and are supported by the two rear speakers which distribute sound all around in 360°, creating a wonderful and comforting feeling in which one is oblivious to the speaker location.


Earlier you mentioned that it was "like a café".

Miura: Yes. Music in cafés doesn't interrupt conversation and you don't get tired of listening to it for long periods of time. You can enjoy these experiences with the sound field turned off.

Please tell us the efforts put into hardware innovations to achieve such an expression.

Miura: The HT-AX7 uses the X-Balanced Speaker Unit, which has been introduced in recent Sony portable speakers and soundbars to achieve the high sound quality required in a compact body. The X-Balanced Speaker Unit is a technology that expands the diaphragm area by making the speaker diaphragm ultra-elliptical in shape, close to a square, to achieve high sound pressure and rich bass. The HT-AX7 incorporates this technology in the front and rear speakers to produce a sound so powerful that it is hard to imagine that it is coming from such a size.

We then customise the individual speakers appropriately. The rear speakers in particular, if you look closely, are not circular but appear wrapped-around, with a matching off-centre central dome.

I see. What are the benefits of this?

Miura: The dome section is positioned at the centre of gravity of the wrapped-around shape to equalise the weight balance of the entire speaker unit for the correct vibration. This reduces sound distortion and enables clear sound production despite the thin speaker profile. Thin speakers also have the characteristic of distributing sound evenly, which also contributes to bringing out the characteristics of the HT-AX7. As the rear speaker unit also needs to be smaller and thinner, we also made an effort to directly attach it on the cabinet.

What about the innovations for the front speakers?


Miura: The front speakers feature X-Balanced Speaker Unit with increased driver power thanks to its longer width, as well as passive radiators on the sides to ensure good production from bass to treble. The high-performance X-Balanced Speaker Unit is more than sufficient to satisfy you as stand-alone active speakers.


Technology and care underlying
the comfort of the HT-AX7


There is also a question on the ease of use of HT-AX7, although it focuses upfront on enjoyment and simplicity. Please tell us about wireless connectivity, one of the technologies that makes this system easy to use.

Itagaki: While Bluetooth is used for communication with the screen device, a unique, low-power 2.4 GHz wireless communication technology serves the front and rear speakers. Such efforts also contribute to the rear speakers being so compact while having a built-in battery that lasts for about 30 hours.

How far apart can the front and rear speakers be used?

Itagaki: It has a transmission range of approximately 10m in the absence of obstructions. In a typical living room, you should not feel disadvantaged. We have also researched wireless communication environments in various countries, including Japan, and have tuned the system to prevent sound skipping.

What else have you focused on besides wireless?

Chijiiwa: The HT-AX7 supports 'multipoint connection', which allows up to two screen devices to be connected at the same time. This means that when you finish watching a film on your tablet and start playing music on your smartphone, the music will start playing from the HT-AX7 without having to reconnect. In the past, you had to disconnect it from your tablet and reconnect it to your smartphone. With the HT-AX7, no reconnection is required. I think this is a very effective feature for the HT-AX7 as it will be often used to switch between multiple screen devices.


When it comes to ease of use, we are also concerned about the initial set-up hurdles, as this is a product that has never been used before. Are there any features available to make it easier for customers who are buying wireless speakers for the first time to use them?

Chijiiwa: The HT-AX7 is compatible with the new smartphone app Home Entertainment Connect, which was introduced with the new HT-S2000 soundbar model launched in June 2023. If you have this app ready when setting up the HT-AX7 after purchase, you can check the HT-AX7's initial settings and detailed customisation using a manual with illustrations. A tutorial is also provided, so even unfamiliar customers can quickly understand how the HT-AX7 can be enjoyed. There is also a link in case help is needed online. Future software updates will also be provided via the app.


Going a step further with environmental considerations and an inclusive design

Recent Sony products have also received recognition for their various eco-friendly initiatives. What kind of initiatives are you taking with the HT-AX7?

Itagaki: As with soundbars and headphones over the past few years, the main unit is made from recycled plastic. A new challenge from the HT-AX7 is the fabric, which, for the first time in a home theatre product, uses recycled materials. By using fibres made from PET bottles, we are taking environmental considerations a step further.

Another major challenge is the use of a unique material for packaging, which we call 'Original Blended Material'. It is made from a mixture of bamboo, sugar cane, and recycled paper.

Packaging using original blended material is now the standard in headphone products, and you are doing the same with HT-AX7.

Osawa: Yes. However, the headphone packaging is different in size compared to HT-AX7’s packaging, so it was a challenge to ensure that it was strong enough. To do so, we decided to go with a double-layered structure. Compared to conventional packaging, this involved lots of work. The result was a packaging with a shock-absorbing function which eliminated the need for cushioning materials. Besides being environmentally friendly, the fact that the product can be seen as soon as the package is opened, makes for a much better experience.


It is nice to know that we no longer need to remove the cushioning material or to throw it away.

Osawa: This is a major progress from the perspective of inclusive design. For example, removing the cushioning material while taking out the product may be challenging for some people. With this packaging, anyone can take out the product immediately. This packaging is not only environmentally friendly, but also creates a new value.


Do try out the different ways of using and enjoying it

Finally, do you have a message for our readers?

Horiuchi: Itagaki: The HT-AX7 is a revolutionary product never seen before. We expect it to be used in ways that we have not even imagined. We hope that those who have purchased the HT-AX7 will enjoy using it in a variety of unconventional ways. If you find a unique way to use it, we would be very grateful if you could tell us about it on social media.

Osawa: No one has ever seen this product before. We strongly encourage anyone to try it for themselves. It will be worth all the hard work if you can hold it in your hands and feel its size, weight, and texture, and if you are surprised at how much sound can be produced from such a small size.

Miura: The HT-AX7 is a product for enjoying a variety of content, but as a Sound Director, I would wish for you to enjoy 'music' at least once. It can be a music streaming service or a live music video on YouTube, as long as you can experience the enjoyment of hearing your favourite music in more lifelike sound.

Chijiiwa: Miura recommended music, so let me recommend 'movies'. The HT-AX7's unique up-mix function converts any video source into spatial sound for your enjoyment, and the sense of realism is truly amazing. This is an unprecedented concept and a considerable challenge for Sony, but we are confident that we have created a product that will please you, and we hope that you can experience it yourself in our outlets.