Final Audio Sonorous IV



Featuring Final Audio’s Balancing Air Movement technology, the Sonorous IV provides advanced performance at an intermediate price!


The Sonorous IV is an audiophile’s dream.

With the synergistic effect of a hybrid design that merges balanced armature with a 50mm diameter dynamic driver unit coupled with BAM mechanism, Final Audio has achieved a clear, vast sound stage with depth to it. With these, the music that seemed to be localized inside our heads with existing headphones vibrates over a large space.

With balanced armature driver units, iron is driven to produce sound, and as such, these drivers face a number of problems, amongst which are “proving tiring to listen to”, “having sound that is subtle and beautiful, but lacking in depth and being flat” and “lacking bass interval”. At Final Audio, they decided to focus on developing technology for the reproduction of bass tones and three-dimensional space with the full-range reproduction of a theoretically unproblematic single driver unit, rather than taking things in a multiway direction. Their team went back to the beginning and reviewed the performance of the balanced armature driver, focusing their attention on something that had previously been overlooked; airflow inside the housing. For the Sonorous IV, Final Audio developed BAM (Balancing Air Movement), a mechanism that optimizes airflow inside the housing through the creation of an aperture in the driver unit, which is usually sealed.

The Sonorous IV, while achieving bass tones and deep, three-dimensional spatial representation, which proved difficult with single driver full-range reproduction, also achieved a BA type that at the same time made for natural listening the user doesn’t tire of.

The Sonorous IV balanced armature driver unit was developed by Final Audio for optimal use as a tweeter. They’ve paid special attention to the choice of materials used in the pursuit of sound quality, utilizing a permalloy with a high level of magnetic permeability in the magnetic circuit.

A driver unit with a diameter of 50mm, is newly designed for SONOROUS. By increasing the precision of the parts, it has become possible to make the gap between the magnetic circuit, the pole piece and the yoke narrower than with common products. A powerful neodymium magnet is coupled with this, making for a high magnetic flux density. The result is clear sound quality.

The Sonorous IV has re-examined the shape of the tangential edge and employed a lightweight diaphragm with a heightened responsiveness to micro-signals.

The voice coil is copper-clad aluminum wire CCAW. Clear, crisp bass tones are achieved with the combination of a magnetic circuit with a high driving force and a light vibration system.

So as not to inhibit the sound emanating from the driver unit, and so that there is no unnecessary added reverberation, a form that is as slim yet as strong as possible has been pursued. This contributes to clear
sound quality.

Ear pads with the optimum resilience for a comfortable fit
What plays an important part in sound quality is the fit between the user’s ear and the ear pad. If there is space between the two, then bass tones are lost; if the ear pad presses against the user’s ear with too much pressure, then apart from it being uncomfortable, the acoustic pressure of the bass tones rise too high, resulting in negative influences on sound quality. In spite of this, there was no evolution seen in the ear pads on the market, and they continued to be made using the same structure for many years.

Final Audio got engineers who had been involved in the development of corsets to participate in developing their ear pads, and re-examined the fit between the user’s ear and the ear pad. By employing the appropriate technology – pursuing synthetic leather with the best elasticity and the best sponge cutting and adopting ultrasound fusion for the adhesion of the synthetic leather to the inner frame – the Sonorous IV is constructed with an unwrinkled, three-dimensional form with just the right amount of tension to it.

A 1.5mm thick aluminum back plate at the back of the driver unit for achieving air pressure balance. Not only air pressure balance but also great results in the suppression of unnecessary vibrations are manifested.

To achieve a high level of precision with the hard matt-finished ABS housing used with high-grade camera lenses, Final Audio conducted a substantial number of simulations, right up to the fluidity of the molding
material used.

They employed a gold-plated monaural plug with a 3.5mm diameter for the connector on the headphones. By employing a connector with a long-standing performance record, we avoided any trouble resulting from poor contact owing to deterioration due to aging. The cable also has a locking mechanism that rotates 90 degrees.

If you haven’t experience what makes Final Audio one of the top headphone companies in the game, and you’re in the Southern California Area, come on into the shop and take a listen!

Additional information

Weight10 lbs
Dimensions10 × 9.5 × 4.5 in



50mm dynamic + balanced armature




8 ohms



Cord Length


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