Interview: Martial Rousseau, Head of Research at B&W


Mis à jour le 26 February 2019.

Martial Rousseau BW

Martial Rousseau is Head of Research at B&W Group. After completing a degree combining physics, acoustics and mechanics, he joined the team of the British speaker manufacturer in 2002. He agreed to speak with us about the new B&W 700 Series speaker range.

The new B&W 700 Series replaces the CM range: why did B&W change the name?

The new range incorporates a host of technologies inspired by or adopted from the 800 series. Consequently, it is a considerable leap forward in terms of sound quality, and we chose to change the name of the range in light of this advancement.

How long did it take to design this new range?

The product development phase lasted about 18 months, but the research that laid the groundwork for components such as the carbon dome and the Continuum cone, for example, began long before that. The research program which gave birth to the carbon dome began in 2013. The Continuum cone, for its part, is directly derived from research conducted for the 800D3 range.

How would you describe the sound of the B&W 700 Series speakers?

Nothing beats hearing them for yourself!  On a more serious note, there is a remarkable amount of coherence between the different registers, in addition to a spectacular stereo image and a total absence of coloration in the mids and highs.

What technologies are integrated into the 700 Series speaker range, and what benefits do they offer?

The 700 Series showcases several of the brand’s exclusive technologies. First of all, there is the Continuum cone, which it inherits from the 800D3 range. This technology restricts the cone?s mechanical vibrations in order to limit coloration in the mids. The functioning principle is similar to that by which a Kevlar cone operates, but with far superior results. Furthermore, the driver fitted with the Continuum cone is decoupled from the cabinet in order to reduce vibrations and further minimize coloration in the mids. Next comes the carbon tweeter, which boasts nearly the same level of efficiency as a diamond dome tweeter. This is obtained by maximizing the initial resonant frequency of the dome, situated at 47 kHz. In certain models, the Solid Body Tweeter-on-top design limits coloration in the highs (thanks to an inert mechanical assembly) while improving the directivity of the sound restitution. Lastly, the bass driver?s Aerofoil cone benefits from a design directly derived from the 800D3 range. This concept is based on the use of a sandwich material which is optimized to maximize overall rigidity. In the 700 range, this is accomplished with combination of a polystyrene core and cellulose fiber.

Why did B&W abandon Kevlar, and what is the new silver Continuum cone made of?

The composition of the Continuum cone is, unfortunately, confidential. However, I can say that it is a braided composite material. This material significantly improves the cone?s performance in the mids and highs, resulting in a more effective control of mechanical vibrations as well enhanced directivity. Consequently, the mids are free from coloration, and the stereo image is stable and detailed.

What are the benefits of the Tweeter-on-top design implemented by the 702 S2 and 705 S2 models?

The Tweeter-on-top design enhances directivity, thus improving the overall sound restitution. In addition, the new Solid Body design, directly inherited from the 800D3 range, guarantees inertia and eliminates coloration in the highs.

What amplifiers would you recommend to get the most out of the new B&W 700 Series speakers?

A neutral and transparent amplifier is best. We obtained particularly good results with Rotel amplifiers.

Has the B&W 700 Series speaker range been developed for both hi-fi and home theater installations?

Absolutely! As for each range of B&W speakers, we spent a lot of time developing the center speakers, and we took great care to obtain a balanced sound in order to ensure that the center channel is well restituted by our stereo speakers.

After the revolution which enabled audio playback control with a smartphone, do you think voice control will win hearts in the hi-fi community?

I think that voice control will have its place and will probably become omnipresent in the near future, even if not all commands are perfectly processed, at least for the moment. My youngest children have already gotten the hang of it!

How do you listen to music on a daily basis, and with what kind of installation’

While I use a lot of online music services to discover new artists, I?m faithful to my collection of CDs and local audio files. I recently acquired a pair of 702 S2 speakers, but haven’t installed them yet. I am looking forward to using them!

Lastly, what is your most memorable musical experience?

One of my most memorable musical experiences, even though it?s not the most recent, was Massive Attack at Brighton Dome in 2010.

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