In high-end audio many speakers are manufactured and marketed commanding serious amounts of money to purchase. Yet they are, in their fundamental design, entirely conventional and follow the same principles as a £150 pair of speakers with the addition of a £150 subwoofer. It stands to question the wisdom of simply refining designs full of compromises and problems that drastically prejudice the possible outcome. Many such speakers suffer from the same audible problems as their cheaper counterparts, despite commanding often 100 times as much money. Few high-end speakers, admittedly, succeed in working around the various issues and reducing them to near inaudible (or at least inoffensive) levels. They do so however at huge material and engineering cost which of course translates to exorbitant High Street prices.

Conventional 2 or 3-way box speakers suffer from many problems, starting with their non-directional low- frequency response which excites room modes and thus compromises the rendition of individual low-frequency notes, with their compromised and distorted transient response due to the internal cavity's resonance (the "room-modes" of the "room" inside the box) and the inevitable colorations introduced by the cabinet walls "singing-along". These intend to completely contain the rear output of the drive unit(s) but usually fail to do so.

Also with their wildly-varying directivity (generally omnidirectional at low frequencies, progressively directional towards the midrange with a return to semi-omnidirectional response when the dome tweeter takes over) results in an in-room response that is usually toned-down in the lower midrange (that's were the actual tone-forming overtones reside) and with a strong emphasis in the upper midrange and lower treble where the "brightness" region of human hearing is located.

Furthermore, by sub-dividing the musical spectrum into several "ways" and reproducing these through independent woofers, midranges and tweeters many other problems are introduced; from a lack of time/impulse coherence through to the inherently different "sound" produced by the dissimilar materials. And let us not forget that the electrical components of the crossover networks also tend to color the part of the music spectrum passing through them.

Instead of attempting to contain and minimize the problems introduced by placing our drive unit in a box (using expensive sound-deadening materials, unusual shapes, extreme sizes, etc.), is it not better to use "no box" at all?
This is exactly what we have done!

Instead of using multiple inexpensive drivers to cover different frequency ranges and shape their response by electrical means using coils, capacitors and resistors to attempt to put back "Humpty Dumpty" after first smashing him to pieces, is it not better to employ a single point-source driver carefully engineered to cover the largest part of the musical spectrum, one that uses the same material for it's entire radiating surface?

When compared to any form of acoustic loading (Reflex Box, Sealed Box, Transmission line and even Horns) we find that speaker placed on a flat open baffle offers a more accurate response to low frequency transients (see Fig 20/4 taken from Reference 3 and reproduced below), a fact that has been known since the 1950's.

An open baffle dipole speaker interacts with the listening room in ways that reduce the excitation of room modes which are the main cause of "boomy" and "ill defined" bass (1, 2). A dipole speaker drastically reduces the colorations of sound radiated from surfaces other than the driver, namely the enclosure panels and secondary radiation through the cone from inside the box. A dipole speaker radiates nearly 5db less sound into the room overall than a normal speaker for an equal sound level directed at the listener, so the room reverb and reflected sound is also reduced by the nearly 5db, especially at frequencies in the fundamental and formant range of most musical notes. Thus by eliminating the Box and placing our Speaker Driver on a plan open baffle virtually all key problems plaguing conventional boxes are eliminated.

When compared to any multi-way speaker system a well engineered single full range driver offers a coherence, togetherness and realism in music that is very difficult if at all achievable with multi driver systems of any kind and especially difficult when using the common Dome Tweeter and Cone Midrange/Woofer-Midrange found in many conventional speakers, be they cheap or expensive.

• It is true that most modern speaker drivers do not perform well in open baffles.
• It is true that a baffle needs to be comparably large to perform well at low frequencies.
• It is true that few well made and balanced-sounding full-range drivers exist.

However once one has recognized the fundamental solution to a problem, the various issues can be addressed and the problem can be more or less solved.

At "3Dsonics" we have created a modern full-range driver specifically designed for use in our open baffle which at 67 x 105 cm is rather small for the full-range performance on offer. The said baffle is made out of 15mm clear acrylic, chosen as much for its sonic as well as its aesthetic properties.

The dimensions of the baffle itself and the precise placement of the driver within, have been calculated according to esoteric numerical systems, thus avoiding the generation of un-wanted resonance.

The Transparence reproduces the frequency range from around 50/60Hz (in room) to 18KHz, time coherent and from a single point source. This frequency range covers practically all fundamentals of the notes found in acoustic music and continues to include all the formants and the overtones for the majority of instruments.

The Transparence provides 106db SPL at 1m and over 100db at 3m listening distance from a stereo pair in a normal-sized living-room when driven by a 10 w/ch amplifier. The Transparence plays as loud driven by 10 watts as many conventional loudspeakers will do with 100 watts. One can even use low-powered valve amplifiers with only 2.5-3 w/ch output (2A3, 45, etc.)

The Transparence minimizes the interaction of the speaker with the room all across the audible spectrum from the fundamentals to the overtones, thus there is no need for expensive room treatments such as big bass-traps and the like. You will experience a note played on a plucked string of an upright bass as a distinct and clear note and not as part of an ill defined low frequency mush. Your virtual soundscape will be clear and detailed, not diffused and indistinct.

The Transparence, lacking a crossover network, places nothing but your speaker cable between your amplifier and the speaker voice coil. It allows your amplifier to assume direct control of the sound output. Therefore the impact of different speaker cables will be quite profound. Bear that in mind when you have an audition.

At the end of it all, as "The Three Initiates" point out, "the proof is in the listening".
You are invited to open your Ears to "the Transparence" and you will understand.

References: 1) "Room Mode Excitation of Dipolar and Monopolar low Frequency Sources", by C. Ferekidis, U. Kempe, Preprint No. 4192, 100th AES Convention, May 1996, Copenhagen.
2) "Investigation of Sound Quality Differences between Monopolar and Dipolar Woofers in Small Rooms" by S. Linkwitz, Preprint No. 4786, 105th AES Convention, San Francisco, September 1998.
3) LOUDSPEAKERS by G.A. Briggs (Assisted by R.E. Cooke, B. Sc. (Eng.) as Technical Editor) - Fifth Edition Completely Revised and Enlarged October 1958