The Danish brand Raidho is world-famous for its high-end loudspeakers. In the top-of-the-line TD series, the TD1.2 represents the "smallest" model. Join me in exploring the exciting question of how big and good a compact transducer can really perform when the effort is taken to the extreme.

My expectations are high and curiosity is great. The speakers are quickly set up and placed in the proven position in my listening room. Though they sound quite good, they don't even come close to meeting my high expectations. I should have known it from the start, this has to be burnt-in - the manual refers to about 250 hours. Lets allow the TD1.2 to follow this guideline and in the meantime deal with the technology of this loudspeaker, which is not exactly lightweight. The makers of the TD1.2 have not failed to treat them to exquisite ingredients. And there isn't anything off-the-shelf - all the drivers are, of course, completely proprietary developments and are handcrafted with a great deal of time and effort.

Let's focus on the ribbon tweeter first, one of the hallmarks of all Raidho speakers. In a ribbon driver, the entire diaphragm is electrically conductive and thus also takes over the function of the voice coil. Usually a wafer-thin rectangular folded metal foil is used for this purpose. Due to the short conductor length, the impedance of this type of ribbon is very low (0.2 ohms to max. 1 ohm). Therefore, an additional matching transformer is needed to isolate the amplifier from the extremely low electrical impedance. Hardly any amplifier likes to drive an almost short-circuited load.

An alternative to this concept is to dispense with a fully conductive membrane and instead use a wafer-thin plastic film to which conductor tracks are applied. With this technique - which Raidho is also using - it is easier to realise an impedance in the normal range between 4 and 8 ohms, as longer and thinner conductor tracks are possible here, running meander-like across the diaphragm. Speakers that make use of this concept are also called "semi" ribbons or magnetostats. The foil used by Raidho is said to be record-breakingly light at only 20 milligrams and a full 11 microns thick. The version of the "ribbon" used in the TD1.2 has also been given a particularly powerful motor that increases sensitivity by three decibels compared to the previous model. The acoustically optimised chamber behind the foil should lead to a further reduction of distortion by 35 decibels compared to the already extremely low values of the previously employed version.

Almost more complex than the construction of the ribbon is the manufacturing of the midwoofer with its diameter of 11.5 centimetres. Right from the beginning, Raidho has relied on composite materials for the diaphragm technology. The advantages lie the individual balance between high torsional stiffness on the one hand and high inward damping on the other. With the technology used in the TD1.2, the effort was taken to the absolute extreme. An aluminum cone with a ceramic coating forms the basis of the diaphragm. Added to this are layers of tantalum, which is extremely hard and stiff, and - yes, you read that correctly - diamond. Raidho specifies 10 micrometres or 1.5 carats of diamond on each membrane. The tantalum/diamond layers are said to reduce resonance by 36 decibels compared to ceramic and to be 50 times stiffer than a pure ceramic diaphragm. At the same time, this is said to have raised the resonance frequency to 20 kilohertz. The result of this enormous outlay is said to be a perfect transient response without measurable distortion. The motor is based on neodymium ring magnets with optimised magnetic field characteristics, which, in interaction with the underhung titanium voice coil wound in flat wire, ensure that an extremely strong magnetic field is created inside the driver. This should lead to a drastic increase in dynamic performance. However, the effort expended doesn't stop with the drivers. The crossover of the TD1.2 was completely redesigned, with the focus on a correct phase response at all frequencies and an optimal impulse behaviour. Only a few, but very high-quality components from Mundorf are used here. The wiring is point-to-point, waiving therefore the customary circuit board.

Each driver is mounted in its own solid aluminum frame, which is fixed to the baffle with four screws each. The frames are rounded to avoid diffraction effects at the front of the speaker. The lower baffle section is slightly tilted to optimise phase response. The curved cabinet, optimised for low resonance, tapers slightly towards the rear and is reinforced by a thick aluminium backbone accommodating for the bass reflex ports. The optimised crossover and the new driver design afore described should lead to a considerable improvement in efficiency - not exactly one of the strengths of Raidho speakers up to this day. In operation, I got by with the modest output of my Omtec CA 25 without any problems.

Meanwile the 250 hours of burning-in time are over and a new listening round is due. The bass reproduction of the TD1.2 is now more precise and the upper frequency ranges have opened up considerably. What remains is a somewhat constricted sound character and a spatiality that is simply not accurate enough for me. Moreover, the integration of low-mid and high frequencies could also be more homogeneous. Therefore, I would like to give the TD1.2 another 200 hours of play-in time.

In the meantime, let's take a look at the accompanying stands. The stands are a clever design in terms of aesthetics and the materials chosen, and they are as light as they look. The idea behind this is that the stand should store as little energy as possible. The vibration decoupling is done on two levels with movable isolation elements, each with some play. The loudspeaker doesn't sit directly on the top plate, but is decoupled from the stand by small discs mounted on metal balls. The stand itself is decoupled from the floor by four feet in a ball and socket arrangement. The whole stand, however, is less rigid than one would normally expect and reminds me of a leaf spring. This impression is reinforced by the heavy weight of the speakers, which cause the stands to oscillate at the lightest touch. Another aspect is the height of the stands, which at 78 centimetres makes the speakers stand unusually high visually. However, a cross-check of the Børresen Acoustics 05 Silver Supreme Edition standing in Dirk Sommer's listening room reveals pretty much the same distance between the bottom edge of the ribbon tweeter and the floor.

Now that I have gained the impression that the TD1.2 are getting better and better from day to day, the time seems right to take a closer look at the placement of the TD1.2. In my listening room, a large base width of more than three metres proves to be the ideal approach. That's more than is usually the case for me, but this way the TD1.2 requires to be angled in a lot. A little patience is needed to find the right balance between base width and angle. But then the sound really locks into place and we are rewarded with an exceptionally wide sound stage without the much-feared hole in the middle. The next step is to find the right inclination of the baffle, which also requires our attention due to the ribbon's dispersion behaviour. Depending on whether our listening position is rather high or low, the speakers may need to be tilted more forward or backward. This becomes audible when the highs are either lacking a little energy or, conversely, when they get too intense. If you are sitting in a low position, try raising the speaker slightly at the rear - if you are sitting high, adjust the inclination more towards the back. Furthermore, the correct tilt angle also influences the accuracy of the sonic image.

The TD1.2 is - as we will find out in a moment - a marvel in many different respects, but for physical reasons alone it cannot do magic in the bass range. I assume that everyone who is interested in a compact loudspeaker is aware of this limitation. Therefore, I will refrain from using justifying descriptions such as "in view of the size" or the like. Let's put it this way: for a wide range of pop, jazz and classical recordings, the TD1.2 delivers a very satisfying low frequency foundation with a clean and fast bass. If you want more of the bass thing, I recommend to think about one or better two good subwoofers.

And from now on it gets a little gushy. For the set-up procedure just described, I used the corresponding test tracks on the Sheffield "XLO Test & Burn in CD". Already at this point I was struck by how extraordinarily realistic the speaker's voice is reproduced by the TD1.2. The sampler Jazz Ballads (Jazz Ballads - 2xHD 24/44.1) offers excellent recordings of beautiful jazz ballads interpreted by finest female singers. Fascinated, I listen to "The very thought of you" with Emilie-Claire Barlow. The singer stands exactly between the speakers and you can almost feel her presence in your listening room. Just as impressive is how precisely and clearly the TD1.2 carves out the differences in the voices of Holly Cole, Amanda Martinez or Jill Barber. What is more, however, it also becomes clear that the recordings were made in different studios - sometimes very intimate, sometimes recorded rather directly and then again rather slightly distanced, which is one of the things that makes this compilation so appealing.

The TD1.2 imparts each individual voice that certain "human element" that makes it sound so particularly authentic and distinctive. This creates a special connection with the listener and makes me believe that I am experiencing it live when, at the beginning of "Tennessee Waltz", Allan Taylor asks his colleague Chris Jones for the right key and then creakily retunes his guitar. When it moreover becomes apparent that Allan Taylor is sitting closer to the microphone and that his voice is therefore captured more direct than that of Chris Jones', it quickly becomes clear what an outstanding speaker the TD1.2 is in this field.

The afore described capabilities of the TD1.2 also fully benefit the reproduction of acoustic instruments. On the album Pepe Romero Flamenco! it can be heard particularly well what skill and musical maturity Pepe Romero already had at a young age. The piece "Jota" combines the highest technical ability with great musicality. With the TD1.2, the sound of the solo guitar is round and full, while at the same time the strokes of the strings are faster, more precise and more dynamic than I am accustomed to. Equally convincing for me is how the high frequency range is able to connect to the fantastic midrange without any kind of break. In the string sonatas by G.A. Rossini for two violins, cello and double bass (Salvatore Accardo - Rossini: 5 Sonate a Quattro - LIM UHD) the strings sound velvety and smooth up to the highest pitches without the slightest hint of harshness.

On top of that there is this unbelievable speed characterizing the performance. In the excellent recording of the "String Quartet Op. 76, No. 5, Finale" by Joseph Haydn (The Nordic Sound - 2L audiophile reference recordings - 24/192), the Engegård Quartet is bursting with enthusiasm and with the TD1.2 we are literally projected into the centre of the string quartet. This impression is intensified by the fact that some corners and edges remain audibly untouched without being pleasantly smoothed out.

If you now have the impression that the TD1.2 only delivers its strengths when performing voices, solo instruments or small ensembles, then I can put you at ease. The TD1.2 shows off its assets with orchestral music as well. The fact that the sound completely detaches from the speakers paired to great spatial depth is something I took for granted in this class. But the point here is how the TD1.2 does this. In the excellent recording of Ludwig van Beethoven's Symphony No. 7 with the Budapest Festival Orchestra (Beethoven: Symphony No. 7 - Channel Classics, 24/96) conducted by Iván Fischer, a huge sound stage is created not only in depth but also in width. Directly behind the speakers to the outside on the left and right, virtual walls of a concert hall are created, giving the sound firm boundaries in conjunction with an excellent depth gradation of the individual instrument groups. Even in fortissimo passages, there isn't any shadow of a doubt as to where each instrument has its place - nothing is blurred or covered up.

One of the outstanding benefits of the TD1.2 is their enormous soundstage - when set up correctly - which dwarfs many a full-grown floorstanding loudspeaker. This does not mean, however, that the TD1.2 will enlarge or even pull apart every recording to a CinemaScope widescreen format to the lateral limits of the loudspeaker. As evidence, let's listen to the beautiful recording of Franz Schubert's "Symphony No. 3" with the Pittsburgh Symphony Orchestra conducted by William Steinberg (Schubert Symphony No. 3 and 8 - William Steinberg - Pittsburgh Symphony Orchestra Spain - HDTT 24/352.8). Here, too, the TD1.2 produces a sound with great spatial depth, but the width of the soundstage doesn't quite reach the speakers - and so the proportions of the recording stay preserved. This is similar to black bars displayed on the left and right of the screen during the playback of a movie.

But with the TD1.2 you can listen to more than just classical music. A good example is "Nothing's Changed" (Joe Stilgoe: New Songs for Old Souls - Linn Records, 24/96): On this track Joe Stilgoe sings his way through a racy wall of brass, while the excellently captured drums really push forward. The horns sound lustrous, but without that overdrawn "bite" and Joe Stilgoe stands genuinely in the room in front of the orchestra excellently staggered in width and depth. In daily use, the TD1.2 proves to be a highly sensitive seismograph for any change in my system. Let me just give some examples: What happens if I use a Toslink cable for the connection between the router and my SOtM switch? What influence do the Ansuz Acoustics Sortz termination plugs have on noise at open inputs (a review is coming up)? Can I hear differences between the different quality levels of the plugs? Yes, the TD1.2 shows every little change as if under a magnifying glass. But lets rather immerge into the music once again.

What always catches my ear after a longer listening session is how playfully easy the TD1.2 reveal subtle details. We can set out to enjoy the relaxing mood with the TD1.2 on the album Remember Love by saxophonist Houston Person and bassist Ron Carter or listen more closely. Then in "Love Is Here to Stay" we hear not only the wind noise of the saxophone, but also how Houston Person takes a deep breath between the passages. But it’s not about these subtleties only that gets me excited about the TD1.2. It’s that certain something that is created by the extraordinarily realistic reproduction of voices and instruments. I contemplated at length about the best way to describe this characteristic feature of the TD1.2: "acutance" is the word which condenses the ability to not let the edges of instruments fade or become slightly blurred. That probably hits the mark best.

Closely related to this is the TD1.2's ability to reproduce fine dynamic gradations within a virtual room. With the "Spanish Overture no. 1: Capriccio brillante on "La Jota Aragonesa" by Mikhail Glinka with Vladimir Jurowski and the London Philharmonic Orchestra (Valdimir Jurowski: 10 years), I listen with fascination to the successive forte entries of the individual instrumental groups during the orchestra's crescendo, while others still linger in the piano; this is particularly impressive when rear instrumental groups, such as the timpani, have already reached the fortissimo and the violins, still playing softly pizzicato positioned in the front of the orchestra, are not obscured by this. On top of that, there is once again this fantastic tonality: The violins sometimes sound velvety and supple, then again austere, the brass sparkles without sharpness, the woodwinds appear either woody and creaky or soft and round.

As you can read by these lines, the TD1.2 leaves me completely enchanted. I'm therefore already dreading the day when they have to make their journey back to the manufacturer. So, let’s conclude with a little musical fun: Louie Armstrong and The Dukes of Dixieland (HDTT DSD128). Louie plays wonderfully his trumpet and sings his vocal solos here on classics that were not part of his usual repertoire, such as "Dixie", "New Orleans" and "Sweet Georgia Brown", which he had never recorded before. The sound stage is again magnificent, you can exactly spot where the instruments are located in the room, and Louie gives us the honour of singing right two metres in front of us!

Nach dem Test zu Beginn des Jahres stand für mich fest, was mein aktueller Traum-Kopfhörer ist: Der Dan Clark Audio Stealth ist nicht nur der bestklingende Magnetostat, den ich je gehört habe, sondern dank seiner geschlossenen Bauform auch noch universell einsetzbar. Jetzt kommt eine offene Variante.

Bisher habe ich unter anderem beim Audeze LCD-X(C) die Erfahrung gemacht, dass geschlossene Kopfhörer nicht ganz das klangliche Niveau ihres offenen Gegenstücks erreichen. Kein Wunder, dass ich nachhaltig beeindruckt war, als mir dann ein geschlossenes Modell begegnete, das alles bisher Gehörte in den Schatten stellte. Da gibt es schlicht keine Notwendigkeit mehr, in einen offenen Kopfhörer mit bestem Klang und einen weiteren geschlossenen beispielsweise für eigene Aufnahmen in recht lauter Umgebung zu investieren. Spontan habe ich erwogen, meine beiden Audezes zu veräußern und einen Stealth zu erwerben – wozu ich mich dann aber doch nicht durchringen konnte.

Dan Clark gelang es, den Stealth so ausgewogen, offen und luftig klingen zu lassen, indem er ihn mit dem neu entwickelten und inzwischen zum Patent angemeldeten Acoustic-Metamaterial-Tuning-System – oder kurz AMTS – ausstattete. Das befindet sich zwischen der Membran und dem Ohr und vereint Wellenleiter, Diffusionskontrolle, Viertelwellen- und Helmholtz-Resonatoren in einer kompakten Struktur: Die Resonatoren fungieren sowohl als Präzisions- als auch als Breitbandfilter, die den Frequenzgang glätten und formen, indem sie die Amplitude der Frequenzgangspitzen und -senken vom Mitteltonbereich bis zu den höchsten Frequenzen verringern. Die Diffusionselemente sollen die Ausbildung stehender Wellen verhindern. Das AMTS sorgt also vorrangig dafür, dass mittlere bis hohe Frequenzen linear, präzise und detailliert wiedergegeben werden. Natürlich kommt das AMT-System auch beim neuen Expanse, der offenen Variante des Stealth, zur Anwendung. Das gilt genauso für den von Dan Clark für den Stealth entwickelten magnetostatischen Treiber, der eine um 20 Prozent größere Fläche besitzt als derjenige, der im Ether2 zum Einsatz kommt. Beim Stealth/Expanse-Treiber wird die Membran mit einem neuen System befestigt, das für eine gleichmäßigere Spannung und somit für geringere Verzerrungen sorgt. Darüber hinaus soll Dan Clarks bewährte und patentierte V-Planar-Technologie den Klirrfaktor reduzieren und die Tieftonwiedergabe verbessern.

Dass in Stealth und Expanse die gleichen Treiber Strom in Schall wandeln, bedeutet aber leider auch, dass dem neuen offenen Kopfhörer der gleiche Nachteil anhaftet wie dem geschlossenen Modell: ein niedriger Wirkungsgrad. Der verhindert zum Beispiel, wie ich im Artikel über den Stealth erwähnte, dass dieser an Kopfhörerausgängen gängiger Mischpulte oder auch dem der Nagra VI nicht betrieben werden kann. Aber wer in einen extrem hochwertigen Kopfhörer investiert, dürfte auch die Ausgaben für einen kräftigen Kopfhörerverstärker nicht scheuen. Abgesehen von der beim Expanse optisch ansprechend gestalteten, offenen Gitterstruktur auf der Rückseite der Ohrmuschel unterscheiden sich die beiden Kopfhörervarianten in ihrem mechanischen Aufbau nicht. Das heißt, dass auch der relativ leichte Expanse sehr lange Zeit bequem und ermüdungsfrei zu tragen und dank der ausgeklügelten Konstruktion des Kopfbügels für den Transport sehr platzsparend zusammen klappbar ist. Ein kompaktes, schön gestaltetes Case gehört auch hier zum Lieferumgang.

Expanse bedeutet übrigens: Weite, Ausdehnung, Raum. In der Broschüre zum neuen Modell führt Dan Clark aus, dass die offene Variante die Darstellung einer noch größeren Klangbühne möglich machen soll: „Expand Your Soundstage.“ Carsten Hicking, einer der Inhaber des deutschen Dan-Clark-Audio-Vertriebs audioNEXT, hatte mir die noch recht spärlichen Informationen und einen Expanse freundlicherweise schon vor der offiziellen Produktvorstellung zukommen lassen, so dass ich den nagelneuen Kopfhörer fast eine Woche einspielen lassen konnte – manchmal sogar 24 Stunden am Tag. Gespeist wurde er dabei von Chord Electronics' HUGO, der teils per USB mit einem MacBook Pro verbunden war, das die Files von Apple Music bezog, teils mit dem angedockten 2go, bei dem die Musik-Files auf einer Micro-SD-card abgelegt waren. Exakte technische Angaben lagen mir beim Verfassen des Textes nicht vor, so dass ich auf die Daten des Stealth zurückgegriffen und sie, wo nötig, geändert habe.

Da die Treiber im Expanse und dem Stealth – wie erwähnt – die gleichen sind, kann ich mir Experimente mit verschiedenen Kopfhörerverstärkern sparen und das neue offene Modell gleich mit dem SPL Phonitor x hören, der harmonierte auch ganz hervorragend mit Dan Clarks geschlossenen Top-Modell. Der SPL bezieht seine analogen Signale von der Digital-Kette im Arbeitszimmer. Um mich ein wenig einzuhören, genieße ich erst Abdullah Ibrahim & Ekayas Sotho Blue und danach Albert Mangelsdorffs Music For Jazz Orchester. Auch wenn letztere einige freie Passagen enthält, geraten die ersten anderthalb Stunden mit dem Expanse zum Genuss: Der Kopfhörer ist auch längere Zeit genau so angenehm zu tragen wie sein geschlossenes Pendant. Noch wichtiger: Es stellen sich auch keine akustischen Ermüdungserscheinungen ein. Die Musik fließt entspannt und kommt mit einer solchen Natürlichkeit rüber, dass man sich über die an ihrer Reproduktion beteiligten Geräte schlicht keine Gedanken mehr macht. Einen guten Teil zu diesem Wohlfühl-Erlebnis trägt auch die Tatsache bei, dass der Expanse eine Menge Details enthüllt und dabei emotional so ansprechend spielt, dass man selbst bei recht moderaten Lautstärken zu keinen Zeitpunkt versucht ist, den Regler des Phonitor weiter nach rechts zu drehen.

Ohne einen direkten Vergleich kann ich schon jetzt sagen, dass mich der Expanse genauso stark für sich einnimmt, wie zuvor der Stealth, den ich erst kürzlich beim Test des Cen.Grand 9i-92SA II wieder hören konnte. Mit dem hatte „Overture – Communion“ von Ruta And Daitya, dem Duo-Album von Keith Jarrett und Jack DeJohnette, jede Menge Spass gemacht. Das ist beim Expanse auch nicht anders: Die Bass Drum wirkt so realistisch, dass man glaubt, sie sehen zu können. Dazu kommen die verzerrten, mit einem Wah-Wah veredelten Sounds des Fender Rhodes: musikalisch und klanglich grandios. Ebenso faszinierend ist das Titelstück, bei dem Jack DeJohnette an den Congas und Keith Jarrett an der Flöte zu hören ist. Der Wechsel zum Stealth verändert den Klang nur marginal. Bei beiden Stücken wirken die Räume nun einen Hauch kleiner, bei „Ruta And Daitya“ scheint sich auch Höhe die Aufnahmeumgebung ein Stückchen verringert zu haben. Die Congas haben über den Stealth etwas wenig Punch, dafür gefällt mir die Bass Drum beim geschlossenen Modell minimal besser.

Da der Unterschied zwischen den beiden Dan Clarks laut Hersteller vor allen in der Raumanmutung liegen soll, höre ich den ersten Satz von Mahlers Symphony Nr. 3 mit dem Symphonieorchester des Bayerischen Rundfunks unter Mariss Jansons, das ja in natürlicher Akustik aufgenommen wurde. Wenn man sich auf den – für mich bei Kopfhörern immer ein wenig schwierig zu beurteilenden – Raumeindruck konzentriert, kann man eindeutig feststellen, dass beim Expanse die Instrumente ein wenig mehr Luft umgibt. Bei Stealth ist Klangbild eine Spur kompakter. Bei Lautsprechern würde man unterscheiden, ob sich das musikalische Geschehen nur zwischen ihnen abspielt oder in Teilen auch noch neben ihnen zu orten ist: Der Expanse erzeugt eine minimal breitere – und bei sehr guten Aufnahmen auch höhere – Abbildung. Das dürfte für wahre Kopfhörer-Aficionados das entscheidende Argument für den Expanse sein.

Ob mit ein wenig mehr oder weniger Luft um die Instrumente: Das packende Zusammenspiel von Slap-Bass, Drums und einer neunköpfigen Bläser-Sektion macht eine Menge Spaß, wenn der Schallwandler dynamisch auf der Höhe und in der Lage ist, tiefe, druckvolle und saubere Bässe zu reproduzieren. Wie „Silly Putty“ von Stanley Clarks Album Journey To Love beweist, lässt der Expanse in beiden Disziplinen nichts anbrennen. Diesen Spaß gönne ich mir dann noch einmal mit dem Stealth. Doch der ist nun ein wenig weniger intensiv als mit dem offenen Dan Clark. Warum ich bei dieser nicht gerade audiophilen Studioproduktion auf einmal einen Hauch Luft und Weite vermisse, ist mir nicht so richtig erklärlich. An mangelnder Einspielzeit beim Expanse dürfte es nicht gelegen haben. Hatte ich beim ersten Vergleich einfach einen größeren Unterschied erwartet oder hat inzwischen der Gewöhnungseffekt an die leichten klanglichen Vorteile des Expanse eingesetzt und es ist wie immer schwieriger vom auch nur einen Hauch besseren zum immer noch sehr guten zurückzukehren?

Bei „Deep As Love“ vom Album Changing Places des Tord Gustavsen Trios probiere ich es deshalb andersherum. Ich beginne mit dem Stealth und wechsele dann zum Expanse. Und nun funktioniert es auch in diese Richtung: Ein wenig mehr Atmen des Raumes, seine scheinbar größere Höhe und eine noch einen Tick mehr fließende Wiedergabe sprechen hier für die offene Konstruktion.