Hello to all!
Thank you very much for the lot and great comments as well for the private messages...
as previously I try to comment in the same order as I received the messages before:
Many thanks that you appointed me to became a member to the Headphone Designers' Hall of Fame.... The honor would be better given to Helmut Ryback - one of the 3 K1000 "Musketiers" as he was the main head for headphone design in the previous AKG years. My job concentrated my focus to microphones and the K1000 driver was a "finger play" for me only sharp before stopping my job... Ok, may sound arrogant, but the technology for dynamic microphone drivers was much more difficult at this times.
AKG never launched true electrostatic headphones. At least till the end of 1989 this was because of the fact, that the effective moving mass of an electrostatic driver is quite high! I know, this sound unbelievable for many members of this forum. But it's a physical fact. This is explained in simple words, because of the "acoustically added mass" due to the front grid holes of the driver and the air cavity between the membrane and the grid. When calculating the total moving mass = membrane + air within the holes and cavities, it was much more than the moving mass of the K1000 driver.
However, todays technologies might chance this view and I would be happy to discuss this point with experts.... because also for an improved "K2000" driver I have enough new ideas based on latest technologies.
Yea! The C414 microphone was really an input for the K1000 frame design.... a little input from my job before
. And yes, I know it was not ideal designed! Sorry for that!...
To the "feeling" that there's a speaker right in front of the ears...: Yes I know - it's true and a drawback of this specific dynamic speaker design. What you feel is the true mechanical moving mass. And this is precisely the main point what I would change with a new design approach based on newest technologies....
The passive electric filter inside the K1000 is to reduce the natural level increase in the area of 3k-10kKz because of the close distance to the ear. May be not very elegant, but effective in term of cost... Of course a DSP active filter could do this job better without phase change... But there would be the need of special amplifiers for the whole product - like the Stax electrostatic systems....
I personally do not believe that any directivity would happen an acoustic influence such close to the ear. But may be any of you can explain so that I understand it.
Again to the frame and grid of the K1000...: I know, it's very heavy designed, but this was not only by excident, it was due to the moving mass. You need a reasonable ratio between moving mass and static mass, so that you do not feel too much from the movements.... As this is quite individual depending, the quotes for the K1000 are also quite different. However, to my understanding the righ next appraoch would be to minimize the moving mass and in the same time the static mass of the frame and grid... Factors of 5 would be reasonable this days...
K1000 a "semi product": All your comments are right more or less. But the main development phase of the K1000 was really not limited to any cost constraints... it was not born on "private initiative" - may be I did not discribe the design phase with correct words due to the fact that english is not my MOTHER TONGUE... The later design phase of the basket and all the mechanical things arround was in quite a hurry ..... believe!
The fact that AKG repair the K1000 still after this long time period makes me as Austrian proud!
"May be that I will bring them my own prototype to repair... may be they find that it offer too much bass
) "
BR heinz