Spirit Torino’s approach in this area it is as radical as it is simple: to preserve the amplifier energy all the way up to the drives, avoiding current dispersion.
To this end, their wiring does not provide for intermediate connectors but is welded directly to the drive eliminating from the path two welding points and a connector contact that cause current dispersion. The search for the cables to be used for this delicate task required years of development and led to a definitive configuration consisting of a braid with 4 anti-inductive coaxial cables, made with very thin class 5 OFC copper according to their own specifications by Italian specialist Tasker.
German Viablue connectors where chosen for single-ended, while Neutrik is the connector of choice for balanced connections.
Starting from the fact that each material has its specific resonance behaviour and that headphones are not musical instruments, but an instrument to reproduce recorded music, the "SPIRIT SOUND" provides that any “colouring” of the sound introduced by resonances of the frame and overlapping the sound reproduced through the drives, must be totally eliminated.
To obtain this result they relied on the study of the behaviour of headset materials and a composite frame has been thus designed that, while respecting the inertial frame requirements, is at the same time transparent to sound.
The frame is therefore made of “Dural” aluminium to which a layer of Dynamat Extreme™ is applied. Dynamat Extreme™ is in turn a composite material derived from car hi-fi applications that adds the damping characteristics of a high-density adhesive putty to a sheet of rigid aluminium.
This dural/putty/aluminium composite dampens the typical resonance frequencies of aluminium, making the inertial frame of the SPIRIT headphones one of the best headphone frames in the world.
A good chassis is not enough without an exceptional engine!
Experimenting with drives led us to Nhoord Audio to become Spirit Torino’s partner of excellence for the supply of “engines”, and subsequently allowed them to develop with them a new drive that, starting from an already excellent base, has achieved the goal we set out to achieve: obtaining maximum speed.
As with the development of an engine, the focus was on the release and intake of the air flows generated by the piston-like movement of the mobile unit. This way the Twin Pulse went from two to four rear ventilation holes thus allowing maximum freedom of movement even at low frequencies and providing an instantaneous impulse response. The rear structure of the drive is heavily treated with petals of Dynamat Extreme™, which are interposed between the vents to make the structure become even more inert, while the membrane surface of the mobile unit is treated by Nhoord Audio with a special gel that optimises the behavior of the drive at high frequencies.
This aspect is very important for a correct sound reproduction in the headphones. If you think about what happens when you talk in a completely empty room: even with very strong concrete walls your voice will always have a booming sound.
To avoid this, the internal walls of SPIRIT headphones are covered by a felt panel that, with its structure, efficiently dampens internal reflections. Another decisive element for the final headphones' sound result is the Pad, or the contact element with our head which in fact constitutes a second chamber inside which much can happen, sonically speaking.
The Twin Pulse Isobaric System® design and its single-drive derivatives, require that the pad be of the open type, in order to allow the pressure wave to vent outwards, without influencing with counter pressure the movement of the mobile drive group. At the same time, the pad walls must not create internal sound reflections therefore two types of high density ZF foam pads have been studied which provide a semi-open cell structure and a shape that guarantees comfort and the right distance from the sound emission point
SPIRIT’s proprietary technology which innovates on the concept of a headphone driver unit, exploiting the concept of isobaric load in a new fashion.
In high fidelity audio, many companies have used this load system, essentially to enhance low frequencies’ output, exploiting the resonance phenomenon of two woofers that, not being loaded in the same way, can have frequencies in which their movement is in counter-phase while in other frequencies the phenomenon of resonance will deliver a peak of efficiency. In the Twin Pulse system, two broadband drives are in “free air” and see the same load, allowing the synchronous movement of the two mobile groups throughout the entire audio spectrum.
To guarantee perfect synchronicity, Spirit Torino carefully couple the drive assemblies with very tight tolerances.
The design advantage of the Twin Pulse technology derives from the two drives working together in the release and intake of the characteristic headphone drives’ air flows, which will be less affected during instantaneous accelerations by the aerodynamic “brake” caused by the rear vents, and also by the greater ability to stop their movement by counteracting the hammer effect generated by the air column contained in the frame chambers.
There are other important features in the Twin Pulse Isobaric System® driver unit design:
In Spirit Torino’s opinion, one cannot claim to know the true potential of a headphone before listening to it with separated masses. Unfortunately, they have mostly only experienced the standard headphones connection whereby the negative pole of the left channel is generally connected to the negative pole of the right, making the two drives interdependent in their movement. To become free from this interdependence as with the separate masses configuration adopted by Spirit becomes essential in order to maximise the impulse response at low frequencies. The advantages of this balanced connection are many and increase if the amplification is correctly designed to work in a balanced current circuit.
As in the motor world of engines, after an excellent chassis and a fantastic engine, come the electronics!
In their experience, Spirit have noticed that listening is easily influenced by irregularities in the midrange frequency response, where the human ear is more sensitive.
Therefore, using a calibrated artificial head, they created a map of the frequency response of their headphones in order to then apply correction parameters at a digital level.
The results of this process are remarkable and allow levels of naturalness of the sound unimaginable before, preserving the original signal since the operation is performed in floating point before the digital/analogue conversion.
The implementation of the maps on the major music players available on the market is under development.
The final setup of such a complex system was the key to the “SPIRIT SOUND” and took three years to research, develop, test refine every aspect of the headphone.
The headband in padded natural leather, the pivotal slides on leather brakes, the choice of sheaths to make the cables flexible and light are just some of the aspects they focused on with the aim of making the “SPIRIT SOUND” experience more and more engaging.