Hello,
First of all I want to thank you very much for all your comments so far.
Especially I want to thank your the link about the 50 headphone benchmarks... At least for the K1000 I assume it's the best overview I read till now.
Also many thanks for the explanations about "openness" of a headphone.
To clear up about the previous design targets we gave ourself during the design phase:
It was the late 80th when the design was fixed and it was the time when computing power to simulate and acoustic know how of for simulation increased dramatic. Also measurement setup was developed to show decay time for all frequencies in one picture.
Also it became understood the difference much better between a far field and a near field sound source.
All this influences lead us to following priorities:
1. We wanted no audible difference from outside source and headphone source.. = "openness"
2. The impulse response should be at least the same as the Jecklin Float
3. The frequency response should be linear between 30 - 22kHz from the driver
I know that many of you would now think that target 2. and 3. goes hand in hand anyway. But this is not totally true when you measure the driver inside the typical headphone "box"
4. The mechanics should be simple and quite "automatically" adjustable as the most AKG headphones offer at that days.
Sorry, I know now that we did not focus anough on the last point and it's may be the weakest point of that design creating worst case a kind of rub&buzz sound and you have to wear the product in sitting or standing position too.
If I would design a "K2K" today, I would focus to improve in following order (priority):
A. The mechanics and the total mass
B. The bass response
C. Easy "wearability"
D. Decrease of moving mass
E. Power consumption
D. Decreased market cost to approx. 800.- €
One point more about practical difference between a speaker source (or better the true source) and the headphone is that the left ear does not hear the sound from the right driver and vice verse.
This effect I cannot change, but AKG offered the "Audiopshere BAP 1000" to compensate at that time. I can really recommend this amp for the K1000 !
As I'm almost "away" from the headphone market since more than 20 years, it's really difficult for me to estimate if the above target list for improvements would be correct so, that a K2K would be a "runner"...
As before ... any further input would be very helpful for me to get an idea for the next steps.
BR heinz