The full story. To the TNT tracker email, Mads had added "sent from Mårten AB with whom we have some cooperation but not on speaker design". The next email would have the added tech info I'd asked for. While awaiting its arrival, I checked out US importer Mark Sossa's catalogue. Beside Qln, I saw the brands Aqua Hifi, Innuos, LinnenberG, Qualiton, Rethm, Clones, Gigawatt and Nasotech - all high performance and quite off the beaten path with its High Street shops. But with our Aqua Formula DAC and LinnenberG Liszt monos, I could actually assemble a full WellPleased AV system. Now back to Mads for the whole tech. "Our core design philosophy is that only the driver should create sound. So we strive to keep the level of parts influence in the signal path to a minimum because we have come to understand and respect how, even at small levels, all parts in the audio chain affect the final result at both a micro and macro level. However, one fundamental part is of utmost importance: cabinet design. First off, the drivers should be acoustically in phase. This is achieved with an angled time-aligned baffle. All of the area around a driver affects the sound so we utilize a truncated pyramid shape to minimize the area around the tweeter. This combined with the felt around it reduces the baffle's effect on the tweeter's dispersion. The rounded baffle edges minimize edge reflections. With the truncated pyramid shape, we also avoid the issue of standing waves within the cabinet. This functional design offers a fundamental advantage and foundation for optimal driver performance to further mitigate the cabinet's influence on the sound.

"Next, a speaker cabinet should be rigid, stiff and quiet. Achieving this is not as easy as one may think. On paper most the stiff rigid materials have low internal damping and materials with high internal damping are too soft for speaker cabinet design. What is normally done to get around this is using hard materials and applying damping materials such as bitumen or similar liners inside the cabinet. This works but is not the most effective solution. We address this issue with a sandwich design—Q-board®—where the damping material is placed inside the board which the cabinet is built from. Vibrations are hereby optimally damped and subdued, with noise substantially reduced. By first building the cabinet to be heavy and rigid, we reduce the initial amount of structural resonance. By then utilising Q-board® which converts vibrations into heat, remaining vibrations are absorbed far more effectively than with any other material. The first Qln speaker was based on this cabinet design. It was called the Qln One and introduced in 1980. Q-board® came by 1984. For drivers, the Qln Signature S3 uses a specially developed 7" Kevlar woofer with a 19mm long voice coil which allows long linear movement. The voice coil is made from Hex-formed pure copper wire. This Hex-formed wire minimizes losses by increasing the number of wire turns inside the magnetic gap. Copper sounds better than copper-clad aluminium, hence no manufacturer bases speaker-cable design on aluminium as a conductor. We use a T-shaped pole piece which creates a symmetrical magnet pattern on both sides of the magnetic gap. This also creates a symmetrical magnet pattern outside the gap."

"Inside the magnetic gap copper rings reduce voice coil inductance and provide constant inductance whenever the voice coil moves within the magnet system to produce increased current at high frequencies. This offers better dynamics at the woofer’s upper range. It also reduces intermodulation distortion. The 7" mid/woofer is based and designed around a coated Kevlar compound with low radial losses. The low-loss rubber surround offers minimal hindrance to the cone’s movement. This Kevlar cone also has a very low material/acoustic self sound and no sharp breakups with high Q resonances. The cone instead breaks up early and controlled which lowers its mass at higher frequencies. This in turn increases response and dynamics at higher frequencies alongside better micro details even for a cone of its size and composition. Furthermore, it allows us to get deep bass extension relative to cone surface and still with superior resolution at higher frequencies. The cone is coated and the woven Kevlar fibre makes for an acoustically very silent cone. The 25mm textile dome is a slightly modified version of ScanSpeak’s Illuminator. The wide surround provides a larger than normal cone area for a 25mm tweeter and a softer suspension which reduces low-frequency resonances far beyond the operating bandwidth. It also creates wider dispersion. The AirCirc motor design with six powerful magnets creates open air flow at the back of the tweeter cavity. Compared to normal ferrite magnets, these flat magnets also minimize the length of the hole in the pole piece to eliminate early reflections and resonances in the back chamber. A copper cap in the magnet system increases current at high frequencies in the voice coil which again provides for more dynamics in the upper frequencies and reduces intermodulation distortion. Response is flat up to 20kHz and just 5dB down at 40kHz.
"In the Qln Signature 3 we use a constant impedance crossover. This is designed so that woofer response compensation and crossover are separated into two parts. First, the crossover compensates for mid/woofer amplitude increase at higher frequencies. Then the crossover compensates for the impedance increase caused by the frequency compensation to achieve flat frequency and impedance. Then the tweeter output is adjusted in level/impedance to the mid/woofer with serial and parallel resistors. This allows us to make a filter between the mid/woofer and tweeter which is theoretically correct so that phase and impedance are practically flat. The crossover is a progressive 6dB/12dB slope. The high- and low-pass are 6dB on the woofer and tweeter, then an octave below/above the filter hinge we add a second 1st-order filter for a final 12dB slope*. This smoothes the phase across the overlap area. We shun all magnetic filter parts so the inductors are exclusively air cores and the winding wiring is baked to minimize physical resonances. All capacitors are polypropylene and all critical parts oil impregnated to prevent physical resonances inside the capacitors. All resistors are metal-oxide film resistors and all components are soft glued to a fibre board, then hardwired.

"The internal cabling is our own design and produced in Sweden. It is based around a 12-segment solid-core pure copper wire wrapped around a polypropylene core. Insulation is pure polypropylene with no additives to avoid colourations. The speaker terminals are massive pure copper. We chose not to use any metallic terminal plate to avoid a charge in the terminal posts from counter-rotating magnetic fields which distort the music signal by absorbing energy. Consequently, more electric power is transmitted. The higher the inductance, the lower the loss of energy and fine details. Hence mounting the terminals directly onto the cabinet, we avoid any metallic interference."

* We'd previously come across such a progressive compound slope with Apertura Audio whose designer Christian Yvon starts with 6dB/octave, then stacks 12dB + 24dB filters atop it.