Home » Review: Jern 11 Loudspeaker- Rock-solid design from Denmark

Review: Jern 11 Loudspeaker- Rock-solid design from Denmark

Review: Jern 11 Loudspeaker- Do not expect a grand spectacle, but nevertheless be amazed by their generous bass reproduction and dynamics.
4.2/5 - (13 votes)

Small speakers, you have them in all kinds and, uh… well, also in sizes. Because nowhere is it described how big a loudspeaker may be before it is no longer called ‘small’. But I am talking about the category of ‘small’ loudspeakers that quickly find their way into the office or the bedroom for many seasoned hi-fi enthusiasts, because “their small size does not make much difference”. However, there are also small-sized people who cannot do anything with the large floor uprights that are often used for ‘the more serious display’. And fortunately there are more and more manufacturers who are also doing their very best in the flyweight class to build an audiophile loudspeaker. I have already had quite a few at home and I am always amazed at how people are able to use the laws of physics more and more. The Jern 11 Loudspeaker certainly belongs in this class in terms of size, but is absolutely no flyweight. The drop-shaped speakers that would fit in a large shoe box (size 46) weigh an impressive 12.6 kilos each. The explanation for this is simple: they are made of cast iron.

The name JERN

In Danish, JERN means IRON, which refers to the cabinet material. We use our special grade grey cast Iron (called Vibrakill ®), with a very high amount of Graphite (Carbon) mixed in the Iron. The Graphite dampens our cabinets vibrations 100 times better than Aluminium, and much better than MDF and wood.
Iron is also much stronger and heavier. This also reduce cabinet vibrations, so you mainly hear the good sound from the loudspeaker cones.


  • Two-way design. Wide phase linear dispersion design. Sealed closed cabinet for best transient response. There is no noise from a bass reflex port.
  • Tweeter Drive Units: Custom Wavecor 22mm. Wide dispersion. Textile membrane. The foam covering around the tweeter dome absorbs diffractions and provides a smoother response.
  • Woofer: Specially developed Wavecor woofer 5 3/4 inch 146mm frame.
  • Excellent mid-range performance due to a new optimized fiberglass cone design.
  • Rigid steel chassis with wide vents for lower airflow velocity that reduces audible distortion.
  • Large engine structure for better control and power handling.
  • Built-in aluminum field stabilizer ring for reduced distortion at high levels.
  • Low loss suspension (high Qm) for better reproduction of details and dynamics.
  • Black plated engine parts for better heat transfer to the surrounding air.
  • Spider Conex for better durability in extreme conditions.
  • Frequency response: 45 – 20,000 Hz in room, -6dB at 65 Hz in anechoic chamber.
  • Measurements by experienced reviewer Paul Messenger showed bass at 32 Hz in his room.
  • Comments: These speakers are developed to work very well close to walls.
  • Crossover: The custom made 6dB / octave linear phase crossover uses a Mundorf polypropylene capacitor and an air core coil. It offers a good 3D soundstage.
  • Amplifier requirements 25 – 150W / 4 Ohm Sensitivity (2.83V / 1m) 86 dB Impedance 4Ω.
  • Accessories: The rubber ring is included with every JERN11.

A closer look at Jern 11 Loudspeaker

Jern is the Danish word for iron, the name could not have been simpler. The designer is Søren Dissing, music lover, audiophile and ‘coincidentally’ the owner of Dansk Skalform A / S, an internationally renowned forge / foundry that can count brands such as McLaren, Daimler, Porsche, Rolls Royce, Siemens, VW and Volvo among his clientele. . He came up with the idea of ​​using carbon-rich cast iron as a speaker enclosure, and so the first Jern 14 was born, which was fitted with speaker units and a crossover filter by a local expert. Ole Lund Christensen, a veteran of the hi-fi world who is also the man behind the Gamut brand, saw these speakers at a trade show and was so impressed that he offered his help in refining the design. The Jern speakers are cast using a special process at Dansk Skalform A / S. The choice for carbon-rich cast iron is not surprising at all. The material is very amorphous, so it has great internal damping – according to Christensen 100 times better than aluminum and ‘many times better than wood or MDF’ – and it can be molded in many shapes, if you know what you’re doing.

Christensen also decided to use a principle that has been used in the car industry for some time for the range of ‘peanut-shaped’ loudspeakers, which consists of three models with a total of 9 variants: reuse of the basic shape. Both the entry-level Jern 11 as well as the Jern 12 and Jern 14 models have the same perfectly finished cast iron housing. The differences are in the used speaker units, differences in attenuation and the tonal tuning of the filter.

The 11 and 12 models are designed to provide a full-range listening experience in smaller rooms by placing it close to the rear wall, even without a subwoofer. If desired, they can be combined with a subwoofer when placement close to a wall is not possible or desired. The Jern 14 models are specifically designed for use with a subwoofer and the recently introduced Jern 15 is aimed at listeners who want to hear a more direct pro audio sound. Later in 2021, Jern will also present On-Wall-Woofers (OWWs), with which the two-way system Jern 11 and Jern 12 can be upgraded to a three-way sub / satellite system , with more lows and a more realistic and dynamic mid / high.

All models have a closed housing that is 30 cm high, 19.5 cm deep and 21 cm wide. Their round shape counteracts the development of standing waves on the inside, while no distortion due to diffraction occurs on the outside. All things considered, this gives Jern practically the ideal shape for loudspeakers. The drivers used in the Jern 11 Loudspeaker are manufactured to specification by the Chinese manufacturer Wavecor. There, Christensen’s fellow countryman Per Madsen holds the technological scepter. He is also a veteran of the loudspeaker world and previously worked at Via and Scanspeak, among others.

The tweeter in the Jern 11 has a 22 millimeter woven textile membrane and the front plate is acoustically damped with cell foam. The Woofer has a 14.6 centimeter cone of woven glass fiber. The units are covered by an acoustically transparent cloth that is stretched on a light plastic ring, which is held on the speaker chassis by means of magnets. One pair of speaker terminals is provided, so no bi-wiring. That’s how I like to see it in a practical sense with compact speakers. The nice regular system impedance is specified by Jern at 4? and the sensitivity is at 86dB (2.83V / 1m) not even that low for a loudspeaker of this size. Despite the closed housing of only 3.7 liters, Jern specifies the frequency range within -6dB at 45 to 20.

Compose and listen

Not so long ago you got a thick rubber ring with every Jern loudspeaker. This served to safely place the speaker at a rear angle in case their setup required it. That way you could direct the sound to your ears, for example when you placed the speakers close to you on a desk in a near-field setup. But because the rings were not used by everyone and their production is not really sustainable, Jern stopped supplying them as standard. They are now available as an accessory, as is a fairly high, slim base.

With me, the speakers were placed on carefully filled / damped NorStone Stylum 2 feet of 60 centimeters. Although they have a small flat piece at the bottom, I found them with their heavy weight and with my rather thick AudioQuest William Tell Zero speaker cables attached to them, so I put four little jokes of Bluetack underneath.

The Jern 11 were turned in quite far, further than I am used to, according to the attached instructions from Ole Lund Christensen. The tweeters were neatly at ear level, and the stands were pushed back until the distance to the wall was no more than 20 centimeters.


The album The Door To The Sky by Orbit Service was allowed to produce the first sounds from record. I know this is a very spatial production, but I was still surprised by the enormous bubble of sound that the Jern 11 managed to project into my living room. Hey folks, this is the better work!

The low that is also abundantly present in this recording did not have the depth and push that I am used to from my own speakers with 11-inch woofer, but what came out of those less than 4 liter-large iron drops still bordered on tangible low. sorcery. Ok, the very deepest basses of the church organ from the Saint Eustache (Récit de Tierce and Taille by Nicolas de Grigny, by Jean Guillou) could not be heard, and Junior B by Yello (on The Eye) also lacked some foundation, but again: what came out was very meritorious and I could happily live with it in a slightly smaller room. By giving the speakers a little less ‘yield in’ (and therefore deviating from Christensen’s instructions), the image became wider without sacrificing focus between and especially behind the speakers.

The little Jerns provide a wonderfully large and deep spatial image. A track I like to use to test that is Springtime Coming Soon by The Nits, from the album Omsk. It contains a number of very unusual percussion sounds from überdrummer Rob Kloet. At one point – I imagine after years of fruitless inquiries – he taps a coffee mug with a key, and that sound was actually about five meters below the floor, as if my new neighbor had broken out our dividing wall and I living room as an acoustic ‘hinterland’.


Small loudspeakers with a relatively low efficiency are usually not known as dynamics monsters, but there too the Jerns managed to surprise me in a positive way. In their performance of Stravinsky’s Sacre du Printemps, the Kirov Orchestra, propelled by Gergiev to great performances, achieves a dynamic that regularly makes you gasp for breath on a large full-range system. And although the scale of that with the Jerns was inevitably a lot smaller, they didn’t really have to be ashamed dynamically. It was a real ‘torture test’ but they fought back.

Speech intelligibility with TV sound (‘Het Journaal’ is a regular part of my test routine) was excellent, the Jern 11 leaves very little in the field of timbre. They are neutral rather than euphoric, but not analytic. Voices like David Sylvian and Ane Brun had timbre and body, and piano (on the incredibly beautifully recorded live album Tripping With Nils Frahm) was powerful, fast and harmonically correct.

Jern 11 Loudspeaker – Conclusion

For just under 1300 euros per pair  at the time of this review  the Jern 11’s offer a surprising amount of value for their money. The fact that they are made of cast iron is not only a nice story for the audiophile drinks table, it really makes sense (figuratively). Their tonal behavior is very neat, they do not really stand out in a positive sense, and their spatial representation is even of very high class. I think they are not really everyone’s friends, their design is perhaps a bit too pronounced for that, although it can freeze and thaw for that matter. In any case, I think they look beautiful and organic, and the female part of my household was also charmed by the white ‘Barbapapas’ as my daughter called them giggling at the first meeting. Well, maybe she was just right about that, because these little speakers did a real ‘barbat trick’ by pretending to be a lot bigger than they actually are.

Sound wise I can not fault it very much, someone who is small in housing and can put a good amplifier in front of it will be able to listen to all kinds of music with great pleasure. Do not expect a grand spectacle, but nevertheless be amazed by their generous bass reproduction and dynamics, and their amazing image and placement. I think you’re a happy person then. A very strong design that deserves an almost perfect review score within its price range.

Positives of Jern 11 Loudspeaker

  • Very spatial representation
  • Surprisingly good low
  • Good dynamics
  • Compact
  • Outspoken design (organic shape)

Negatives of Jern 11 Loudspeaker

  • Must be placed near the wall
  • The deepest layer (<40Hz) does not come out nevertheless
  • Or a subwoofer or the soon to be introduced OWW
  • Outspoken design (not everyone’s friends)

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