Brochure

The graph on the left demonstrates the principle of the tuned mass damper. In red, an m1-k1 mass-suspension system displays a pronounced resonance. Adding an m2-k2 device (upper
section of the diagram on the right), generates two resonance spikes (represented by the blue curve on the graph). The anti-resonance dip associated with the resonance of the main
system produces the green curve. Finally, by tuning the damper, we obtain the purple curve, practically quashing the resonance entirely.
Our tuned mass damper (TMD) incorporates two bulges molded into the surround.
This simple solution, adapted with our new software, stabilizes the surround from
adverse resonances, which avoids cone deformation without disturbing its dynamics.
TMD Tuned Mass Damper
Midrange obsession
Midrange drivers are without a doubt the most
difficult to master in an acoustic system. Timbral
consistency and imaging depend on an even
transition of energy from the bass woofer to the
midrange, and its subsequent coherence with
the acceleration and dispersion of the tweeter.
A substantial 6" (15cm) midrange satisfies the
first requirement, which in turn complicates its
coherence with the tweeter.
Over the past 20 years, we
refined the "break up" (the
frequency at which a cone
deforms and generates distor-
tion) of our 3
rd
-generation "W"
Composite Sandwich Cone and
drastically reduced resonance
in the IAL-2 tweeter.
Now, we can go one step further
thanks to finite element limit
analysis (FELA). Our team
developed simulation software to visualize the
dynamic behavior of the surround that binds the
cone to the basket, thus exposing suspension
performance issues that required closer attention.
One common solution consists of increasing
the mass of the surround, which unfortunately
decreases definition. Our solution derives from
technology used for passive seismic
vibration control and racecar
suspensions: a Tuned Mass Damper
(TMD), controlling resonance
by counteracting it. Applied to
speaker drivers, our patented TMD
suspension incorporates two bulges
molded into the surround, the
dimensions and positions of which
are calculated to counter balance
each other.
Having eliminated distortion issues at their source,
we could then create a hyperbolic cone to increase
frequency response – and correspondingly, impulse
response – to further increase definition.
Sopra’s midrange
driver produces
astounding realism
thanks to its new
magnetic circuit and
TMD suspension