Orthodynamic emitters

I want to tell you a little about non-standard speakers. Orthodynamic loudspeakers were invented, like many good things, in Japan and have been used for a long time in many models of Yamaha, Audio Technica and others. The structure of such speakers is both simple and complex. In fact, they are two round magnets and a membrane between them, which form a kind of sandwich.

The trick of this technology is that they are magnetized in different ways, in different parts of the magnet. In concentric circles, similar to the annual rings of trees, the areas of different poles cover the entire magnet, diverging from the center to the edges. In the illustration, the south is marked with red, so you can roughly imagine how this is all located. Now let’s move on to the membrane. Unlike a dynamic system, this is not a diffuser glued to a magnetic coil, but a thin membrane on which a conductive track is applied in a spiral.

The tracks were applied either by etching a previously applied layer of metal foil, or by gluing a ready-made spiral onto a lavsan membrane. With a film thickness of 5-8 microns, Lavsan had an extremely low weight, comparable to the weight of air vibrated by a film. When the current was applied, the spiral generated an electromagnetic field, which began to interact with the constant magnetic field of the pancake magnets, and as a result, it began to vibrate and generate sound. The emitter itself looks like this:

This technology has one main advantage: due to the extremely low mass of the film membrane, the level of distortion is very low and is close to ideal. This is already a hi-fi class. Orthodynamics was used almost exclusively in headphones, and in fact for them it was created as a modification of the earlier technology of isodynamic emitters. The principle of operation of both technologies is fully described in the corresponding patent.

Now I want to argue why I classify headphones created on this technology as Hi-Fi.

• Orthodynamic headphones sound very accurate and true. There are no senseless bullying of bass and treble, the middle does not sink at all.
• Due to the low inertia of the membrane, the microdynamics are impressive, all the smallest details of the sound are very well conveyed.
• The power of the headphones is very high (to be honest, it is excessive at maximum power, it is very real to go deaf).

Like any non-mass technology, it has its own nuances.

1. Such headphones almost certainly require a special headphone amplifier. Without it, they will also sound, but “not so”.
2. They require warming up. Seriously, if the headphones haven’t listened for a month, it will take them 5 hours to achieve their ideal sound. With daily listening, 5 minutes of warm-up is enough.
3. The quality of the sound source should be very high, as well as the quality of the recording.
4. You have to love them.
5. When listening to modern recordings on these headphones, you need to understand that now music is recorded in a slightly different way than it was done 30 years ago. Music in these headphones will sound completely different.
6. Real gurus achieve the optimal sound for themselves by choosing the optimal amplifier and changing the damping of the headphones.
7. Most headphones don’t have deep pounding low bass. Headphones may not bring pleasure to fans of the “brain removal”. At the same time, there are models that cover the entire range – in general, this is the so-called vintage sound.

The largest number of models were produced in Japan by Yamaha. There was also a wide range of headphones in the USSR. The last headphones produced in the CIS were ECHO N-16-40 C made in the city of Smele.

The latest models I know are produced by the Japanese company Fostex.

The TDS-15 also had a membrane, but it did not have a spiral, but parallel tracks. Once I disassembled them, but I failed to put the magnets back without damaging the membrane.

Sources:

The article was compiled on the personal initiative of my beloved Echo N-16-40, which I dreamed about and asked not to forget about them. Thank you for the attention.

PS Earlier I collected a collection of Soviet headphones and sometimes I think to come back to this.