Final Audio Design Sonorous III Closed Back Headphones Review


Image copyright belongs to Final Audio Design.


The Final Audio Design Sonorous III Closed Back Headphones were kindly provided to me by KS Distribution free of charge in exchange for a fair and unbiased review on No additional compensation was given in exchange for posting this article on my blog.

The Final Audio Design Sonorous III’s are available in the UK from at a cost of £299 with free P&P. In the US the Final Audio Design Sonorous III’s are available from at a cost of $399. (Prices correct at time of posting).


To enlarge an image and view its description, please click on the image.


One of the most relatable comments I have read about the Sonorous III’s (a review on sonicelectronix) was “My only complaint is these headphones are addicting” and with all my heart, I couldn’t agree more, trying to write the sound quality section of this review was quite honestly an annoyance as all I wanted to do was listen to the music. For me this is a rarity as I oft far more enjoy writing about products than I actually do using them.

The 16 Ohm impendence means that no additional hardware is required to drive the Sonorous III’s and they are as happy connected to a HiFi as they are a laptop, tablet or phone. An example of just how easy they are to drive, I am yet to take them above 30% volume on a laptop and very little further on tablets and phones and I seriously struggle to see what benefit a headphone amp would offer.

Considering how easy they are to drive they are very well suited to those seeking to attain the best quality possible from their portable devices without compromise. Unfortunately, while the isolation is impressive during playback considering the closed back design there is significant leakage more akin to an open back and the lack of a bundled carry case will mean those seeking perfection on the go will need to make an additional outlay to protect their investment with the Final Audio Design Semi Hard Carrying Case.



The Final Audio Design Sonorous III headphones come supplied within a high quality, although rather basic retail style cardboard packaging. On the front is an image of the headphones along with Final Sonorous branding and on the rear is a cup dissection diagram along with some product bumpf and specification information in multiple languages.


Opening the box up you are greeted with a rather complex plain brown cardboard insert on which the headphones are retained without any further protection and a clear resealable plastic bag contains the following accessories…

  • A good quality illustrated instruction manual in English, German, French, Spanish, Dutch, Russian and Chinese (I think) with just 2 pages of information offered per language.


  • A gold plated 3.5mm to 6.35mm adaptor.


  • A 3.5mm male stereo jack to dual mono 3.5mm male jack cable, which will be discussed in-depth shortly.

Having reviewed rather a large selection of headphones in my time I have to confess that the overall packaging is at best lacklustre, it’s good quality, but rather basic for such a premium product. I also have to confess that the lack of a case, even if it were but a cheap velvet effect drawstring bag to protect your precious investment from dust is equally as disappointing.



  • Headphone Type: Over Ear
  • Cable: Removable single stereo 3.5mm jack to dual mono 3.5mm jack (each cup has separate inputs for left and right channels) with a twist lock connection
  • Driver Size: 50mm
  • Driver Type: Dynamic
  • Earcup Design: Closed back
  • Frequency Response: Unknown… I’ve read three different answers, but can’t find anything official
  • Impedance: 16 Ohm
  • Signal to Noise Ratio SNR: 105 dB
  • Weight: 410g (this is just the headphones and the cable adds 40g)



The Final Audio Design Sonorous III’s do not have a hardwired cable, it is removable and replaceable, on the underside of each cup is a recessed 3.5mm socket with a twist locking mechanism to secure the cable to each of the cups.

The supplied cable measures just shy of 160cm long (including the connector jackets, but not the connector pins) with a single 3.5mm male stereo jack on one end and two 3.5mm male mono jacks on the other end (one to connect to the left cup to provide the left channel and one for the right cup to provide the right channel).

All three connectors are identical in style, shape and size, well, except for the two twist locks pins found on the mono connectors. All connector pins are gold plated with a 4.5mm long, 5.5mm diameter black plastic spacer between the pin and the jacket to aid with the fit on mobile devices especially those used within cases.


This spacer on the two channel jack (that plugs into the audio output device) is plain, but with the two mono jacks that connect to the headphones this is where a small set of plastic wings are found that secure the cable to the headphones by inserting and then twisting the connector 45 degrees.

The connector jackets are made from aluminium with a mirrored silver finish and somewhat resemble the style of a reversed bullet casing with the main body measuring 8.9mm in diameter tapering to 6.5mm at the rear where the cable exits the housing.

Curiously, at the rear of the jacket there is no additional reinforcement where the cable exits, although I suspect that the tapered section at the rear of the jacket provides this function and also considering the thickness and quality of the cable additional protection is most likely not required. In truth, I guess that only time will tell, and worse case scenario, it shouldn’t be too difficult to source a replacement, such is the reason a replaceable cable is so desirable at such a price point.

The cable that exits the rear of the stereo two pole 3.5mm jack measures 3.96mm in diameter and located 104.5cm down the cable is the splitter that separates the cable. The split is reinforced by a housing and jacket that is visually almost identical in style, size and design to that of the connector jackets found at the ends of the cable.


At the opposite end of the splitter two separate wires protrude for the left and right channels measuring 2.93mm in diameter and 46.8cm long between the splitter and rear of the mono connector jackets.


As for the cable itself, this is rather similar to the Fisual S-Flex design only much thicker, the cable is coated with a matte black PVC sleeve that offers absolutely no resistance when dragged across a multitude of surfaces (or more importantly garments) and is entirely limp being able to coil the entire cable up in a loop less than 2″ in diameter. This cable does have a tendency to tangle if not correctly coiled before storage, however given the slick nature of the PVC sleeve all that is required to untangle is to hold one end and give it a couple of shakes.

While the 3.5mm stereo connector jacket is entirely plain the two mono connector jacks sport a discreet “L” and “R” indicators for correct placement of the connectors in the ear cups and the splitter jacket bears an equally discreet “Final” branding with a tri hexagon logo.


While this cable is hardly thin or light it is compared to most cables I have encountered with over ear headphones and Final have clearly made the effort to produce a set of audiophile quality headphones that are usually found only used in the comfort of ones home suitable for use on the go… at least for those who passion for music is matched by their confidence in wearing such obvious headphones in public.


While the Final Audio Design Sonorous III are clearly not intended for use in more rigorous activities, those wanting to use them on their daily commute will want to source a lapel clip as the transfer of noise caused by the cable rubbing on clothing as you walk along can be a source of annoyance with quieter tracks.

Overall the cable is a very nice quality product that compliments the Sonorous III’s well, I’m just glad they didn’t make the mistake of going overboard with the branding on the connectors as they have with the headphones themselves… that said there are those who like to show off such things so each to their own.



I have to confess initial impressions out of the box were mixed, but in the 5 days I have thus far been using the Sonorous III’s my appreciation for them has grown insurmountably since the first time I held them in my hands.

Once I had got the packaging and any prejudice caused by it out of my mind, I began to appreciate what I could see, feel and hear. While some may feel it wasteful I genuinely believe that the packaging needs improving as when spending this much on a pair of headphones it is not just about the performance, but also about the experience.

If you struggle to comprehend this have a look on YouTube for a video of someone having their million dollar Bugatti Veyron delivered in Russia on the back of a 50 year old rust ridden tow truck and you might begin to understand. (Not that I am saying the packaging is as bad as that).

Anyway, rant over so lets take a closer look…

Starting with the headband this measures approximately 58cm long (measurements taken on outside, or top if you prefer) and it is fixed place and does not expand, to adjust the cups they slide up and down the headband. At its core the headband is made from a varied width, 1.48mm thick band of stainless steel with a brushed effect finish.


At both ends of the headband a 14.5cm length of bare stainless steel is exposed measuring 23mm wide at the top and 16mm wide at the bottom. This section of the band is contoured at a 110 degree angle, providing a level of sprung torsion allowing the headphones to be expanded for all manner of shape and sized heads.


At the very bottom on both sides of the bare section of the headband is a 13.92mm diameter black plastic disc on the inside and outside surfaces that bear “L” and “R” indexers for correct placement of the cable and ear and also serve to prevent the ear cups from sliding off the headband.

As noted earlier the cup placement is adjusted by sliding them up and down the bare stainless steel sections of the headband, this action is consistent and suitably stiff as to prevent unintended of accidental movement requiring the use of two hands to adjust each cup when the headphones are not worn on the head. On the head sufficient force can be applied for adjustment with the use of a thumb on the underside of each cup while retaining the headband in position with the remainder of your hand.

At their shortest length of adjustment the measurement from the top of one cup to the other is just over 26cm long on the inside edge of the headband and from the base of one to the other measures approximately 46cm. It should be noted that when the cups are set at this shortest the bottom edge of the bare stainless steel section of the headband protrudes from the bottom edge of the ear cup by approximately 2.5cm.


With the cups moved all the way to the base of the headband (set to their greatest length) the measurement from the top of one cup to the other on the inside edge is approximately 34.5cm long adding a further 20cm if you want the measurement from the bottom edge of one cup to the other.


Some rough measurements of my head are as follows…. middle of ear over head to middle of other ear is approximately 41cm and the circumference of my forehead, around the top of my ear is approximately 61cm. With such a sized head, I find that setting each cup 7.4mm short of its greatest expansion provides a perfect fit.

At the top of the bare stainless steel section of the headband, black plastic caps are found bearing Sonorous III branding on the outside edge that serve to secure the padded section at the top of the headband in place. These caps are made from two sections of very high quality ABS plastic bearing a smooth but slightly textured finish that are screwed together, clamped on to the stainless steel band with no evident seam.


The padded section of the headband at the top measures just over 22.5cm long (at the top), 32mm wide at its narrowest point and 49mm wide at its greatest. This section of the headband is covered with a very soft, silky smooth synthetic leather with a seam evident on the front and back edges.

Located between the stainless steel band at the top section of leather is a semi rigid piece of unknown reinforcement that serves to prevent the leather coming into contact with the stainless steel metal band (which if it did would eventually wear a hole in the leather). On the underside between the metal band an exterior leather is a thin layer of foam padding, the total thickness of the padded section of the headband at its greatest point is 12mm squashing to a minimum of 4.5mm.

Finally, we come to the cups themselves, these are clamped onto the bare stainless steel section of the headband with a ball joint articulation hidden within the cup that has an action that can only be described as one that an amateur filmmaker could only dream on having on their tripod, it’s a small detail but it is beautiful to behold.

The articulation of this ball joint is approximately 15 to 20 degrees forwards and backwards, 15 to 20 degrees left and right and 40 degrees up and down. I know it sounds silly, but audio quality aside, it is easily my favourite feature of the Sonorous III’s.

The construction of the cups themselves is rather complex and best illustrated with pictures rather than words. They are largely created using the same plastic as found on the headband that retains the padded section in place with a simple silver metal detailing between the cup and padded ear surround.


The ear surrounds are covered with the same soft plush synthetic leather as found on the headband and the padding provided is via a 22mm wide, 19mm thick foam with no memory retention. The space within the cup for the ear measures 57.5mm in diameter (they are round) and 18mm deep.


Obviously, as the surrounds are foam there is a degree of give, that said with ears larger than one would call average that semi stick out (although nowhere near a full on Prince Charles) I had absolutely no problem with space and if anything they felt light and airy, neigh even near cavernous compared to some over ear headphones I have tried in my time. Thankfully, these pads are easily replaceable, replacements, however, are far from cheap at just shy of forty pounds a pair.

So as I said earlier, at this time of writing this chapter I’ve had the Sonorous III’s for about 5 days now and while my initial impressions out of the box were of indifference I have clearly formed a bond with them that can only be described as paternal and when they sit on their stand beside my monitor I do not think there is anything else more beautiful to behold.



Firstly leakage, to put things into perspective, I should first note that I find a comfortable listening volume to be in the region of 15% when the Sonorous III’s are connected to my workstation laptop and 30% was about the limit my ears could take. At a distance of 75cm from another person in a room with an ambient sound level of 23dB only a faint noise was heard when the volume level was above 14%.

With the volume level set to 30%, even at a distance of 8m in a room with an ambient sound level of 23dB sound can be heard coming from the Sonorous III’s. While the design may well be that of a closed back cup the fact is leakage wise, they act more like open backed cans and due to the 16 Ohm impendence at max volume they could quite easily compete with a midi Hi-Fi system for output.

Next up is isolation, sat in front of a slightly noisy workstation replacement laptop on a cooling pad and typing on a Cherry MX Brown mechanical keyboard at arm’s length the detected sound level next to my ear was 67dB. Wearing the Sonorous III’s with no audio playing the fans on the laptop cooling pad were just about evident and so entirely is the keyboard although the frequency is much lower.

With the volume set to 14% (the point where there was no leakage evident to the person sat next to me) I could not hear anything while typing, only the music playing. While the leakage may well be poor at higher volume levels in a public place they can still drown out at least 67dB of ambient sound at lower levels.

Finally, we come to comfort and fit. The Sonorous III’s, even by over ear headphone standards have large cups and they are an ill match for the young or those of a petite stature. While the degree with which the cups can be adjusted is commendable the size of the headband even with the cup positioning shortened as much as possible the fit will be sadly too limp for such individuals.

Thanks to the ball joint mounts on the cups that offer an excellent 3 dimensional articulation even those with prominent facial features will find that as long as their head a remotely near that of an average adult they should find the Sonorous III’s comfortable with little in the way of a clamping sensation.


I earlier noted some measurements of my head and to complete the picture my head is a sort of round shape squashed in at the sides with no prominent features such as jaw or cheek bones. For me a perfect secure fit is easily attainable and they are entirely comfortable to wear and secure with only the slightest clamping sensation on the back of my jaw.


During my audio testing of the Sonorous III’s I had no issue for the first 3 hours with a 1 or 2 minute break every 20-30 minutes due to interruptions. After four hours I started to develop a very mild headache, that cleared after a pause of about 15 or 20 minutes.

Despite having a closed back over ear design and pleather surrounds, after wearing the Sonorous III’s for such a long period I did not suffer with overheating or sweaty ears and even after 4 hours I only just noticed them starting to warm up, no doubt thanks to the very spacious cups.



Prior to conducting any sound testing with the Sonorous III’s they were first left to burn in for approximately 40 hours on a pink noise loop, in a few weeks when I have more time I will run the loop for longer and report back in the comments section to see if this made any difference.

The following sound quality testing was conducted using 320kbps MP3 tracks with the Sonorous III’s connected to a Samsung Galaxy Tab S2. It should be noted that these headphones are ridiculously easy to drive and when connected to a laptop I would consider a comfortable volume level to be 14% in a quiet room with my maximum threshold being  25% to 30% and at 100% they could be quite frankly used as speakers rather than headphones.

Having done a little research prior to my review consensus implies the Sonorous III’s are best suited to Instrumental, Rock, Indie/Alternative and Classical and less so for Hip Hop, Rap, Pop or Dub Step. While I do not claim to be an audiophile and I bow to the superior knowledge of my betters, I have done my best to articulate the quality as best as possible with a selection of music from various genres.

Metallica: Nothing Else Matters (Metallica & San Francisco Symphony Orchestra).
Simply outstanding, I’m on my third play through and I’m seriously struggling to write comment as the track is so enthralling and consuming. Separation is frankly above and beyond. Not wanting to gross people out, but the only comparison I can make is the difference in sound after having your ears syringed, I have never heard the intro of this track sound anywhere remotely as crystal clear as this before.

This is likely to be the strangest comment that anyone has ever made in a headphone review (or at least the second strangest after my last comment), the performance could only be described as Metallica as brought to you by Disney. The only comparison I could make is to listening to a grand orchestral piece in a Disney film in the comfort of a cinema, it was that good.

Strings are simply angelic and the balance even at the high end is sublime, the bass is entirely natural and for the most part tight, between 0:17 and 0:26 however the deepest notes evident through the track are a little wobbly with some notable reverberation. Overall 4.8/5

Nirvana: The Man Who Sold The World (MTV Unplugged).
Performance erred towards the higher end (most notably the vocals) and the bass while clean, felt a little weak and is perhaps best described as neutral. Guitar riffs, however simply sounded first hand rather than reproduced and the instrumental section is most defiantly the highlight of the track. Overall 4/5

Bob Marley: I Shot The Sheriff.
Well, one things for sure these headphones would be a lot easier to review if they were worse as I’m spending far more time listening than writing. A handful of Bob’s high notes were a little harsh, again, it did err towards the high end and the performance by the 3rd play through was becoming slightly fatiguing, otherwise highly enjoyable. Overall 4/5

Rage Against The Machine: How I Could Just Kill A Man.
The deepest bass lows are a little flat and it does overwhelm both the vocals and other instruments. In 0.40 when the electric guitars come into play the entire track falls apart and it becomes rather harsh and quite chaotic. As much as I love RATM, I simply could not bear to listen to the track a second play through to make more detailed notes. Overall 2/5, in stark comparison listening to the original by Cypress Hill straight afterwards I could not find a single flaw or point of detraction and it was without doubt the best performance I had ever heard of the song, 5/5.

Cage The Elephant: Ain’t No Rest For The Wicked.
Easily the sweet spot for the Sonorous III’s, that said the guitar riffs only evident on the left channel (by design) sounded disjointed at times, 4/5.

Nero: Doomsday.
The highest notes were slightly harsh and the Sonorous III’s do err toward the higher end resulting in a little bit of a fatiguing experience. I’ll freely confess this sort of thing isn’t usually my bag, but with some very light tinkering with an equaliser this performance would make most small town night club sound systems weak at the knees. I’m not quite sure what the basis was for people claiming these aren’t suitable for Dub Step as it took less than 5 seconds effort with an equaliser to tame the high end. Overall 4/5 (or 3 without adjustment).

The Fugees: Ready Or Not.
Again, I can not see the reasoning for claiming the Sonorous III’s aren’t as well suited to R&B / Hip Hop, balance was as far as I could tell perfect with the snare / cymbals being handled with precision, genuinely very hard to find any fault. Overall 5/5, that said Ooh La La La by the Fugees sounded rather unpleasant, it’s hard to describe, but the performance sounded washed out, chaotic and very fatiguing 2/5.

Other songs that were a joy to listen too were…
– Coldplay: The Scientist, 4/5
– The Cranberries: Zombie, 4.5/5
– Johnny Cash: Hurt, 4.5/5
– Iron Maiden: Run To The Hills, 4/5
– Dire Straits: Romeo and Juliet, 5/5
– Beastie Boys: Intergalactic, 4/5
– Gorillaz: Clint Eastwood, 4/5
– David Bowie: Space Oddity, 4.5/5
– Queen: Somebody To Love, 4.5/5.5
– David Bowie: Life On Mars, 6/5
– Pink Floyd: Wish You Were Here, 4/5
– Massive Attack: Unfinished Sympathy, 5/5
– Macy Gray: I Try, 5/5
– Tracy Chapman: Fast Car, live version = 4/5, studio version = 3/5
– P!nk: Family Portrait, 4/5

Some that were about average…
– Quindon Tarver: Everybody’s Free, 3/5
– Dolly Parton: Jolene, 3/5
– Righteous Brothers: Unchained Melody, 3.5/5
– R.E.M: Losing My Religion, 3.5/5
– Primal Scream – Loaded, 3.5/5
– Alanis Morissette: Ironic, 3.5/5

And some that were not….
– Alicia Keys: Empire State Of Mind, 2.5/5
– Dido: White Flag, 2.5/5

Thank you for taking the time to read this review, I hope it has been helpful to you. If you have any questions or comments regarding this review, please post a comment below and I will do my best to answer them.

Final Audio Design is a registered trademark of S’NEXT Co. Ltd.

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