PureArtFi LS-6 design philosophies
The LS-6 project melds state-of-the-art hi-fi with the speaker as a fine furniture object. Using hardwoods and handmade craftmanship yielding beautiful objects for use in discerning homes where music is an important part of ones lifestyle.
In 2019 the dream team of Bruno Putzeys, Lars Risbo, and Peter Lyngdorf announced an audio company named Purifi. A team with such beyond reproaches credentials and history of successes in both the commercial and academic sides of the HiFi industry bears watching. They announced breakthroughs in understanding hysteresis distortion resulting from iron and steel components applicable to both Class-D amplifiers and loudspeaker drivers. This led to the introduction in 2020 of the first Purifi woofers touted to “crack the extended-stroke code”. The “code” referenced is the fact known to loudspeaker engineers and advanced audiophiles that despite appearing on paper to have identical air moving capabilities in use traditional 12” and 15” short stroke woofers sounded better than 7” class long stroke woofers. The design and use case dilemma this created is that bass systems using 12 to 15 inch woofers require large refrigerator sized enclosures. Such mammoth boxes are welcomed, even celebrated, in dedicated single purpose listening rooms and home theaters. In more typical multi use spaces such outsized boxes are rejected as out of balance for harmonious living spaces. The “extended-stroke code” Purifi cracked is the complexly interrelated factors that kept long excursion drivers producing higher levels of inter-modulation distortion (IMD) when using their long stroke capability to make deep loud bass. In HiFi such claims of breakthrough are essentially a weekly occurrence. Given the credentials of the team at Purifi and their explanations of the multiple techniques brought to bear in early 2020 a shipment of first production PTT6.5 woofers and passive radiators were brought in for testing. From the first test boxes the results can be described as ‘gob smacked’ and ‘stunning’. The promised bass depth and volume is delivered, beyond that the reductions in distortions across the drivers’ entire operating range brings a clarity unique to the luxury woofer segment. For the next two years all our loudspeaker developments centered on extracting the maximum performance from this true break though driver.
Clean and simple the exterior design features the rectilinear design elements that predominate in most homes’ interior designs. Hiding the speakers’ technical complexity inside the enclosures allows the cabinetmakers art to come to the forefront using selected solid hardwoods and veneers. Master cabinet building beginning with CNC machining then onto traditional bench craft and hand tools fabricate the enclosures. Multiple layers of hand rubbed oil finishing brings out the wood’s beauty as no production line sprayed finish can. The vital ingredient being the decades of experience in bespoke cabinetmaking and finishing that are brought to bear.
Finding a tweeter system to reproduce music’s’ treble tones that is as low in distortion and dynamic as the Purifi woofers proved a challenge. The solution is a horn waveguide loaded ribbon plainer type. Hidden inside the enclosure a large back chamber damps and absorbs the driver’s rear wave opening up treble dynamics and ‘air’.
Woofer and Enclosure
It is very common in HiFi to claim a ‘breakthrough’ for incremental improvements. Purifi’s woofers base technologies are real major improvements to the state of the art based on rethinking of first principles. The resulting lowering of measured distortion is clearly audible as a clarity, depth, and dynamic openness one typically only hears from the best large format drivers in very large enclosures. Purifi’s 6.5 inch woofer and dual passive radiators provide the LS-6’s midrange and bass system foundation. Every prototype using this state of the art redefining driver set sounded great. As development progressed it became apparent the extremely powerful motor system pumps both a tremendous amount of music into the room while also dumping higher than usual reaction forces into the enclosure. Each enclosure upgrade to stronger more inert techniques yielded audible improvements. Ultimately 1+ inch thick panels, constrained layer damping, and limp mass damping were brought to bear in the enclosure’s construction. The resulting system sets the music free from the distortion added by typical less overbuilt woofer enclosure systems.
A carefully refined crossover circuit seamlessly blends the drivers together. Every component in the crossover network is audio grade. Inductors all feature air core construction and generous wire gauges. All capacitors are polypropylene types designed specifically for HiFi use. Internal wire and connectors are specified to assure no weak links exist in the crossover system. The physical realization of the circuit is point to point wired with the tweeter and woofer sections separately housed within the enclosure reducing cross talk. Each section is enclosed in a damped box that serves double duty breaking up the enclosure’s internal volume standing waves further lowering resonance effects.
Speaker stands designed specifically as part of the LS-6 system complete the aesthetic design ensuring pride of place once installed. The stands also feature fasteners into the speakers improving stability, de-coupling dampers improving sound, and internal wiring paths allowing a visually clean connection to the amplifier.
Ordering the LS-6 begins with your desires, as a bespoke product we will discuss topics like wood options which leads to resulting finish options. From those choices a delivery time can be estimated. Once the build parameters are set a down payment starts the build. From time to time there are available built units as an option should they fit your needs. Use the 'contact' button to start the process.