LITHOS

ACOUSTICS

ADVANCED SPEAKER RESEARCH FROM INDIA

No Listening Fatigue

Kontra - Design and Engineering

1. Separate Subwoofer and Satellite Cabinet per side:

When the bass driver is housed in a separate cabinet, it affords unique advantages. The cabinet size is optimized for the correct transfer function; low frequency vibration is prevented from interfering with the midrange and high frequencies. This minimizes intermodulation distortion and vibration. Further, the satellite sitting on top of the subwoofer is isolated with a specially designed curved stand mounted on thick isolation spikes housed in a neoprene rubber base. Thus, individual cabinets perform their duties better, and more economically.

 

Other, conventional high end speakers (with all drivers housed in a single cabinet) spend their money on 1 most important thing - the cabinet. Extensive materials, thick walls and elaborate bracing not only add to the bulk, but most importantly, to the cost that you pay.

2. Diffraction Controlled Satellite Shape:

The shape of the Kontra satellite is truly a case of form follows function. This unique design narrows the cabinet dimensions along each individual driver - preventing sound waves from diffracting around large areas. This means no time domain smearing along the cabinet edges, and coupled with a superb thin metal cut out grille, the sound is launched cleanly and without fuss into the listening area. Might we add that even though form follows function in this case, the result is true sonic and visual harmony.

3. Fast Acting 100Hz bass filter in satellite:

Most speaker companies allow their midrange to work down into the bass, or their bass drivers to reproduce midrange up to 300 Hz. This is because it is easier to design a solution around these criteria. This is not correct. A 5” midrange reproducing 100Hz and above, will have typically no visible movement. However, when it is asked to reproduce bass, it has to physically move.

 

The midrange frequencies are now launched into the listening room from a moving cone (because it is reproducing bass as well) - this causes Doppler distortion.

 

The Kontra crossover prevents the midrange driver from reproducing bass by using 24dB bass filters at 100Hz, preventing Doppler distortion. The midrange of the Kontra sounds natural and clean, fast and immediate. You will find it very hard to get a cleaner sounding midrange in this price and far above.

 

Furthermore, by using the same 100Hz filtration in the woofer, the bass is prevented from reproducing any midrange - the bass is fast, clean and tight. With no overhang and boom.

4. Complex Response Shaping Crossover:

We always maintain that the crossover is the heart of the speaker system, and the Kontra crossover goes further in using complex response shaping to deliver accurate, neutral and uncolored frequency response throughout its bandwidth.

 

To start with, any crossover has to be designed around the drivers. But little known (and definitely less practiced) is the fact that even the cabinet size plays a part in the crossover design. Our complex response shaping takes into account seldom-addressed parameters in speaker design.

 

The baffle step response problem causes a diffraction effect that raises the frequency response of a speaker typically starting between 500-700Hz. This causes a thinning of the sound at these frequencies and results in a frequency response that makes the sound bright, thin and fatiguing. This also results in an apparent lack of bass in the system and many of these speakers have to be placed near a wall to overcome this problem. Complex response shaping calculates the rise of this parameter due to the baffle step and accurately corrects this problem, for a smooth, flat midrange response, on or off the wall.

 

Metal cone drivers are a double edged sword…they have less breakup and tend to sound faster than other conventional materials, but they also have high intrinsic resonant points that cause severe spikes in the response resulting in ear fatigue. At the onset, the sound of metal cone drivers is exciting and appears very detailed. However, soon fatigue sets in and the over detailed sound begins to reveal itself for what is really is - high resonant spikes in the frequency response. Our careful choice of cone material uses a blend of metal titanium dust on a mica cone substrate…this tempers the metallic sound, yet reveals it’s advantages. Further, complex response shaping eliminates those frequency spikes that result in response anomalies even an octave after the crossover point. This prevents any edginess and fatigue and gives a natural, detailed and musical presentation of the music.

 

Our crossover is a complex 31 element engine (including the bass filter) that typifies the involved approach to network design that is at the heart of all Lithos speakers. With 1) all response anomalies taken into consideration and corrected, 2) inductors arranged to minimise emi and crosstalk, 3) impedance curve flattened out for easy interaction with any amplifier, 4) the usage of high quality elements like air core filters, drum core filters, dual-parallel capacitors and 5) high quality internal wiring, it’s not surprising that the sound delivery of the Kontra will surpass all expectations at this price point.

5. Unique High Density Cabinet Isolation Membrane:

The most important consideration of cabinet vibration damping is in the low frequencies. To start with, the use of a separate satellite and subwoofer cabinet makes this problem easier to tackle. Once physical separation is achieved between the low and midrange frequencies, we can optimize the bass cabinet accurately and efficiently. The Kontra has a unique high density absorbing membrane to isolate and absorb low frequencies. The membrane is organic, flexible and has the density of cement! This effectively isolates the low frequency and prevents the cabinet panels from absorbing excessive energy. Thus energy storage effects (where the cabinet absorbs excess low frequency energy and re-radiates this at a later time) causing smearing of the sound in the time domain, is eliminated. Bass transients are truer and more natural, tight and fast. The use of this membrane, to our knowledge, is the first for any speaker - worldwide.

6. Q balance technology for no listening fatigue:

The Lithos Q-balance technology is being appreciated by audiophiles the world over - and is the central theme around which our speaker designs are based. For more information on Q-balance, do check out the info and technical sheet on Q-balance.

7. Drivers:

The Kontra uses a complete new set of drivers as compared to other previous Lithos speakers. These drivers have been selected after careful listening and studying of their engineering parameters.

Woofer:

The job of the woofer is to reproduce accurately and realistically the low frequency spectrum of the music. In this case - from 32Hz to 100Hz.

 

The 8” cone is a propriety cone material using a laminate of different polypropylene films and adhesives. This creates a stiff but still dampened cone that will remain stable even under very large sound pressures. A long, 4 layer, 1.25” voice coil housed in a very narrow gap, optimizes sensitivity, power handling and transient response time.

 

The Aluminum Short Circuiting Ring prevents motor distortion in the voice coil.  At the same time, this acts as a heat sink for the voice coil, reducing power compression. There are 2, lightweight adhesive bonds on the Dust Cap. This way the dust cap and cone will respond to every coil movement accurately and without breakup.

 

The progressive suspension is designed to achieve soft clipping and low distortion even under extreme load. The open-backed spider is ventilated to achieve the lowest possible compression and allowing air to flow freely to create a cooling effect for the voice coil. The rigid cast basket with an aerodynamic profile provides the necessary sturdy base for the magnet structure and suspension and allows for the long excursion of the cone.

Midrange:

 

The midrange in the Kontra reproduces the critical frequencies from 100Hz to 3KHz. There are 2 midranges per speaker - aligned around the tweeter in a controlled directivity design. This allows the sound to interact minimally with the floor and the ceiling, and not loose sensitivity over long distances. The midrange is a unique component, with a multilayer cone material and a dual magnet system.

 

Like the woofer, once again, a sandwich cone, with a base made of mica filled polypropylene, and coated with a layer of titanium. A rigid, double bonded dust cap acts effectively as a single extension to the cone and reacts with its every movement, to prevent break-up. The dual magnet allows for higher strength, sensitivity and a faster transient response.

Tweeter:

 

Like the midrange and the woofer, the tweeter is also specially selected to respond accurately to the signal input, and more importantly to blend with the midranges to deliver a coherent, seamless high frequency. A 1” silk dome, with an open chassis front plate structure, allows the tweeter to have air and dispersion. The tweeter has a powerful Neodymium magnet and a unique rear wave cancelling chamber. This not only prevents interference from rear high frequency waves, it also acts as an isolator for the midrange spectrum as well.

7. Drivers:

Taken to the next level for the Kontra, this effectively works around making the cabinet stiff and rigid. These two parameters push the resonant frequencies of the cabinets higher and thus allow for easier elimination of low frequency resonances.

 

The woofer front and rear panels are sloped inwards, to extend rigidity and minimize bass standing waves. All panels in the woofer are 19mm MDF. Coupled with the high density isolating membrane, the woofer cabinet is stiff and rigid…thus maximizing low frequency clarity and detail.

 

The satellites are made with solid cut out 19mm panels for the sides and braced internally. All panels for the cabinets are cut-etched into each other and pressure bonded with epoxy resin. This forms a single monocoque shell cabinet which is highly inert and ideal for sound.

 

The stand over the subwoofer is dual isolated with thick spikes housed in a specially made tapered centre receptacle, further housed in a rubber packing to prevent any residual vibration from the 2 cabinets interacting with each other.

 

The overall strength and rigidity of the cabinet prevents excesive energy storage and the dual isolation between the satellite and the subwoofer prevents modulation distortion. The  weight of overall speaker is 32Kgs (each) - ensuring a solid, precise and clean output, a remarkable engineering achievement.

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