Behind the Design: The Astro Bluetooth 'Pure Audio' Speaker

If you sit a computer all day, you likely have a speaker sitting there next to you, and if you like to take that speaker with you, it’s likely a portable, Bluetooth speaker. The sound quality among these is typically so-so, good enough to get you through the day. Most wouldn’t know the difference in the sound unless all the options were compared side-by-side. So, when I heard about the Astro ‘Pure Audio’ Bluetooth speaker, I was curious. And when I saw a side-by-side comparison, I was blown away. I’ve now used it for a few weeks and it is, without a doubt, the best portable, Bluetooth speaker I’ve experienced. I wanted to find out more behind this speaker, so talked with founder Alexis Corval about everything from the concept and industrial design to the audio design and manufacturing.

The Astro speaker is a development of Swiss brand Tree-Labs by a self-identified team of audio geeks. They’ve apparently hit upon something as their Kickstarter campaign has blown past the goal. For a speaker that’s promoted at a lower price with higher quality audio than the closest competition, it’s not surprising.

Tree-Labs sent the new Astro speaker over, so I’ve been comparing it between my favorite oontZ Angle, my Sonos PLAY:1 and other headphones and desktop speakers. It blows the oontZ away. It’s not in the same class as the Sonos, and definitely doesn’t have that deep bass, but the clarity over the Sonos is magnificent. They’re billing the speaker as “the worlds first ‘pure audio’ Bluetooth speaker.” Honestly, I hadn’t heard the term ‘pure audio’ before–thought is was more a marketing gimmick–But it made sense when I cranked the volume. I usually can’t push the volume on these desktop/bluetooth speakers, but this thing doesn’t even lose fidelity, snap or crackle at the highest volume. That, with the wireless range and the battery life leave me listening to it all day and locking this baby up while I’m asleep.

Along with taking a different approach to the audio, they’re taking a different approach to the design, both in materials and in cosmetic appearance. On the latter, they’re teaming up with top-ranked tattoo studio, Tattoo Temple, for a range of cover art for the speakers. They’re fabulous.

The Tree-Labs team started development of Astro about three years ago. For them, it was the continuation of what they had already been doing in portable speakers. Having developed bluetooth speakers for different American and European brands over the years, they already had extensive experience in the field, but had the desire to do something that was completely their own.

They had one goal: A speaker with the best sound quality and the most simple design possible. Oh, and all of that in a portable, Bluetooth, battery-operated format. Simple right? Well, it turns out there’s quite a process behind a simple design in a simple package, and Alexis broke down every single aspect for us.

INDUSTRIAL DESIGN

This is the first thing we worked on. I wanted to do a minimalist design that was in line with the style of Dieter Rams and the functionalist school. I wanted to have only one control button on it and all the lines to be as simple as possible, with the only standout design element being the side O-ring which serves as the key design point and also serves as a carrying point by passing one finger through it.

The size and shape of the device were also key. I wanted something that was flat (not too much depth) to ease portability, was solid looking and felt “right” in size for the sound that was going to come out of it (That’s actually something I spent a lot of time on, because it’s something that could kill the speaker if we don’t match the amount of power with the size.)

THE PROCESS

1. Hand drawings: First, I would create differnet hand drawings of different versions. In general terms, I would do three to five different versions. Then we would focus on one and I would revise everything until satisfied. In this particular case, it was really in terms of eliminating elements and keeping it as simple as possible. This is the stage where materials already start to be considered.
2. Paper samples: This is specifically to confirm the general shape and size. To make sure it “feels right.” At that point we were already starting to consider what kind of hardware would go in and whether it would be appropriate.
3. 3D drawings cosmetics: We use SolidWorks for this. The first step is to do a cosmetic drawing without final considerations of the construction and assembly of the parts, so it’s all about the external appearance at this point. We go through multiple iterations of this until it is the representation of what I envisioned.
4. 3D drawings mechanical: We use SolidWorks here also. At this stage we translate the design to something that’s designed internally, externally and with consideration of actual production. Materials to be used are set.
5. CNC sampling: This is where we see the first sample. Materials are very close to what will be used in the end (even though they are not exactly the same as the materials used for CNC which vary from the ones that are used during production) and we can finally see things in detail.
6. Revision of the design: After seeing the first CNC sample, details are worked out and improved. Some of the main things that were looked at are angles, thickness of materials and dimensions. At this point, I remember we revised the O-Ring quite a bit. We also worked out the angles and radius, so it felt right, and we increased the size of the button and repositioned it so if also felt right. We also increased the depth of the design at this point as we were already working on the internal part and we felt the extra depth was needed for extra space of the parts and for audio considerations. A lot of details are worked out and 3D drawings are revised and sampling is redone until satisfied.
7. Final review: This goes along with the audio development (covered below), but basically, at this point, we confirmed everything and we are ready to start tooling.

Functions

• As the idea was for the product to be as easy to use and with the bare minimum set of functions we set on only one control button with only the essentials: turn it on, pause the music and Bluetooth pairing. This comes along with the charging and the external auxiliary ports which were set in a recess with a removable cover for dust and splash protection.
• I really wanted that anyone could use the product right out of the box. All the functions that you need are already on your source device, whether it be a smartphone, tablet or computer and end consumers are already fully familiar on how to operate these.
• The only 2 functions we added aside from ON/OFF are Pause, which is really an emergency button in case someone walks in the room or you get a call or something similar like that. The other one is the Bluetooth pairing button which needs to be there otherwise to change form one source to the other you would need to turn off Astro and restart it which would be annoying.

Materials

We are using the following main materials:

1. ABS fiber glass reinforced cabinet: Using fiber glass is an old Audio trick where you use whatever you can to reinforce the cabinet to get a better audio response as it’s stronger than just standard ABS.
2. Silicon surround piece: This makes the finished speaker shock proof and it also adds a really nice feel both to the touch and to the eyes. I really like working with this material. It’s a lot more expensive than using some other types of substitute materials such as ABS with a satin finish on it or TPR, but it has a lot more nobility to it and is also really unlikely to go bad and is more durable. It also helps with the sound.
3. Aluminum button, front and back dust covers: Aluminum is a great materials as it is light and has a lot of great properties. We used a stronger grade than usual to work our way around bending during the manufacturing process and also during its life.

Audio Design

This includes hardware, electronics and software design as it is all linked. This is probably what took the longest time to work out. First, developing a battery-operated speaker is a lot different than developing a standard speaker–it’s actually really hard to achieve good sound quality with a battery-operated speaker and even some of the biggest names in the field mess it up. In order to get good sound on a product like Astro, you have to work and excel in many areas (and failure in one area basically makes everything else crash):

1. Drivers: The drivers in Astro are 100% custom made. We worked from the ground up to build our drivers. There are a lot of parts in a driver and we worked on everyone of them in order to get a driver that was as full range as possible and with as little distortion as possible for its size and power rating (6 Watts per driver for a total of 2, so total 12 Watts). We started with a 50mm diameter width of driver versus the most common 40mm size used in most Bluetooth portable speakers, which gives a lot of advantage in term of the range and details. The process on this was basically the following:
   • Specify parts needed and assemble them.
   • Test using Audio Precision equipment frequencies and other standard audio measurements.
   • Actually listen the drivers with a pair of ears (unfortunately a lot of sound engineers seems to skip this part…) as the results only tell a small part of the story.
   • Adjust parts dimensions/materials. which can require new tool or CNC (depending on what is required).
   • Repeat until satisfaction is achieved.
   • There is a passive radiator to the front which also require a similar process to the drivers but is a bit simpler to work on. Each change requires a minimum of one week to get the new parts. Testing normally takes 2 days to go through (both equipment testing and listening testing).
2. PCBA, Amplifiers and power supply: These are really difficult to work on in small size speakers too, because all the parts used affect the sound in equal part as the drivers themselves. Luckily we had a lot of experience in this department as well, but we wanted to push the envelope as far as we could. The process went pretty much like this:
   • Once functions and dimensions are set, create a PCBA layout and work our way to a first sample. It takes about a month to get everything done and get the parts in hands and assembled.
   • We would power and audio test on this using AP equipment (Audio Precision).
   • From there, it’s similar to the driver development, as we would tweak manually parts and layout in order to test and improve response, power, etc. We would use our drivers to do testing as well as to perform listening tests.
   • Once we render the PCBA useless we would restart from the beginning and work on a new PCBA based on what we learned, and improved.
   • A key point is that everything affects the sound quality so there is a lot of room for experimentation there. For example even the battery affects the sound quality a lot. Everything matters.
3. Bluetooth chip: We like to use CSR chips, which are the most reliable and most commonly used in the market for the higher-end Bluetooth speakers.
4. Software: Aside from basic power and function related items, we keep things to a minimum. We don’t use DSP in our process for example. There is DSP available in components found on our PCBA such as the Bluetooth chip and amplifier, but we don’t use it. We like to develop our sound with everything else I described but we don’t like to use DSP for the simple fact that it changes the sound in a bad way, distorting the frequencies and even going to the point of removing some of the layers of the sound. Unfortunately DSP is very easy to use, it takes a few minutes to adjust sound via DSP and get some “improvements” and because of this it is widely used. DSP is also a good way to compensate for the weakness found in the drivers and electronic structure which would normally result in distortion but are removed via DSP at the detriment of a better sound.

Packaging

We went with a carton shock-proof design. I wanted to keep the general idea of the shape of the speaker (flat) and keep things as simple as possible and in line with what the design of the product is.

Manufacturing and Quality Control

Here are some of the main points. ASTRO already has gone through a Pre-Production phase where a small batch is produced exactly as it should be done during a master production (MP) phase and during which any issues can be worked out before MP.

1. Drivers: We are working with a specific supplier for this. We teached them how to assemble our drivers as they are quite complex. A point of interest is that drivers are mostly glue, as everything is glued together. Small size drivers are a pain to manufacture, because of their size. Most of the assembly is done by hand for these. After we received them, they go through 100% QC on our end before assembly.
2. Mechanical parts: Silicon uses a different process than standard plastics such as ABS which are injected. The process is more of a cooked process with the mold looking like a waffle mold in the shape of the part and the materials placed in it and then cooked. Our Aluminum front and back dust covers are stamped from Aluminum sheets, the front dust cover requires three steps in order for the front perforations to be created without breaking the aluminum plate. Everything is checked 100% again prior to assembly.
3. Electronics: All the parts come from all around the world and are then assembled via SMT at a third party. Upon receipt, we test everything again 100%, testing power and Bluetooth properties among other items.
4. General Assembly: The internal parts are screwed, glued or sonic welded together. There is a final check on the sound and all the functions for all the speakers and a cosmetic final checkup. Finally, everything is moved to a final assembly line where there is a final cosmetic check up and everything is packed (speaker, cables, instructions and packaging and barcodes and inner cartons and master cartons).

The pre-production versions of the speakers are already out and with the Kickstarter funding going through the Astro speaker is clear to move into Master Production. Being able to move straight into production is a key aspect to a successful Kickstarter campaign and where Tree-Labs obviously knew they needed to be once funded. When you look at this little speaker, you would agree it looks simple. The process however, not so much. As Alexis says, “Everything matters.” It’s clear they understand what it takes to bring a product to market and based on the sound that’s coming out of my speaker right now, it’s clear they have a understanding of how music should sound.