For me the AKG K340...
They were the flagship of AKG 40 years ago...
Their double new innovative technologies at the times are always new even today...
First : Hybridation of dynamic cell with electrostatic... Second: An array of tuned Helmholtz resonators inside creating a dual acoustic chamber...
Kennerton cie said to me they tried for years to design a working hybrid without success... That speak volume about the task...
Too complex and then too costly to make and too much research to create a good really working design...
AKG terminate the K340 not because it was not a good design, it was the best they ever create, patented by Dr. Gorike, one of the founder, but they terminate it because not only they are difficult to drive as the Hifiman He 6 , but they are most picky for their amplification than any headphone...( not surprizing because they are two cells inside and a crossover transformer and a grid of resonators)
And without optimization work inside them and around them ( in my case 6 modifications) , they may present an "apparent" mismatch, of variable size, between the two drivers speed dependant of the way you use them...But this apparent mismatch come mostly from our habit of listening to ONLY SINGULAR DRIVER headphone with no resonators inside...We must learn how to listen to a new soundfield experience to understand how to use them and which modification to implement...
The soundfield of the K340 is unique and when optimized is SPEAKER-LIKE and natural and dependant of the recording album and give me "OUT OF THE HEAD" complete experience ... All my other headphones sound artificial, always inside my head, and to be frank are used only in my trashbin or for the computer needs now ... Not for music... And i tried 2 Stax, two planar, many dynamics, they all never compare to my speakers/dedicated room at all anyway unlike the K340 ...
The K340 alas! is too difficult to understand for " beginners", i will not recommend it bec ause i dont want the responsability of misguiding people, and the K340 will present apparent mismatch, and boominess, that completely DISAPPEAR when optimized with the right source, amplification, pads, cables, equalization for each cell, and some modification for vibrations controls inside and the cut off of the protecting obstructing plastic grid between ears and one of the cell which was only there to protect the product not for acoustic...
In the scale SOUND QUALITY /PRICE paid, nothing can beat them i paid them 100 bucks... ...And we will wait to see another TRUE hybrid because of complexity of design and cost...The Enigma Dharma was not a true hybrid using only an electrostatic cell at 12,000 hertz as a super tweeter...Not as the K340 at 4000 hertz where the living presence of voices and piano are located ...Here the two cells work together at the same degree... And the Dharma own no internal tuned resonators which make possible not only a 3-D holographical sound but make possible deep and extended bass completely clear under 30 hertz...
The K340 is unique and will stay so....i can replace all my other components and upgrade.... Not the K340.... No headphone will beat it on ALL acoustic counts only on some factors separately and the price will be in the many thousand dollars to do so not the 100 bucks i paid for...
I even discovered a new acoustic factor listening to them which is nowhere mentionned and used in reviews of headphone , i never experienced this acoustic factor with any other headphone...
The thre main acoustic factor are:
---Distortion
---Timbre
---Immersiveness
Immersiveness is made in all reviews by all reviewers of two acoustic factors:
---Imaging differentiation of each sound source ...
--- Soundstaging dimensions of ALL sound source together
But most reviewers never described this one THIRD factor clearly :
--- Holographical 3-D volume associated with each sound sources accordingly to the ORIGINAL RECORDING as it is translated in a VOLUME SPACE for each instruments and chords by the headphone...Not a 2-d surface...
Why most reviewers missed this acoustic THIRD important factor of immersiveness ?
Because the Hybridation of the K340 with the internal set of 5 tuned Hemlholtz resonators work inside the shell acoustically as the many Helmholtz resonators i used in my dedicated room worked, making me able to feel this holographical volume for each instrument and chords in my room ... In my other headphone this holographical volume of each sound source or instruments is nearly reduced to a surface INSIDE the head...The soundfield of the K340 is never inside the head but around the head at worst or outside it partially or completely, it is recording dependant, a recorded church chorus dont give the same soundstage than a small jazz trio in a studio...
Then the immersiveness factor which in a room is determined by the acoustic ratio between the sound source (ASW) and the listener envelopment trade off balance, or ASW/LEV, is, with the shell/drivers of the K340 , translating the recorded album, determined by the acoustic content of the cups to recreate this ASW/LEV ratio ... And the Helmholtz principle of absorption/diffusion/reflection play the same in a room or in a shell...
And the dual chamber inside the K340, created by back waves and direct waves ratio differences between the two cell and the action of the passive tuned resonators FOOL the brain and compensate in a way for the lack of crossfeed and time delay we experienced with speakers...The time delay between back waves and direct waves in the shell fool our brain and make us able to recreate an holographical 3-d localization outside the head...Dr. Gorike was a genius... Most reviewers miss it completely... And they perceived mismatch where there is none because they were not able to understand the specific acoustic properties of this marvel...
Then immersiveness in headphone listening is related to three factors not two...
The complete soundfield dimensions immersiveness are : imaging, soundstage and 3-D holography...
I experienced it with the K340... Not with any of my 9 others headphone, all with singular driver in empty acoustic shell as most headphone at any price are mostly ... Dr. Gorike, i learned it reading his patent, is a physicist specialized in acoustic not an electrical engineer... Thats tell the tale...
For sure this K340 will not replace a Choueri BACCH filters DAC, but i can live without it , to some degree it approximate speakers listenings in a way any other headphone cannot... :)
