Jermo K
Sponsor: Sennheiser
Hi, thanks for the kind words and great questions.Hi Jermo,
Couple of questions for you.
1. In the most recent video you talk about FR not being the entire story with HE90 (something I certainly agree from personal experience) with the diaphragm weight and other mechanical aspects playing a large role in the sound. We have been seeing a fair number of large names in the space going further and further into the idea that FR dictates all due to headphones being largely minimum phase devices (which they do seem to be, and the argument seems to make sense to me at least). What do you think is missing from the conversation here to truly talk about the difference that make HE90 and HD580 (both tuned quite similarly IMO) such wildly different experiences? Is it as simple as our measurements maybe arent viewed with high enough resolution? Or is there something more fundamental that is being missed?
2. I am an HE1 owner and have had the chance to play with HE90 on several amps as well. Frankly, I don't think HE1 holds up to HE90. While the internal dac of HE1 is fairly lacking IMO (about similar to a bricasti M1SE non-mdx IME), HE90 realistically out performs HE1 in a lot of ways even off of much less dacs but with propper amplification. Is there something about the can its self that is limiting this? Or if we were to find/make a way to use a better external amp would HE1 end up scaling similarly to HE90?
3. Any plans to publish at least the pinout/headphone specs for HE1 so a new amplifier could be made? Tangentially related, any idea on what the tube requirements are for HE1? I would love to roll it and from what I can tell the 802s are JJ 12Au7s (a tube I'm quite familiar with the options for) but do you actualy need a matched octal? Two quads? Are there very specific Gms and such that are targeted (given the fact that tube replacements come with specific locations)? Or am i even off base on what the tubes are?
Thank you very much for your time and I love seeing senn back active in the comunity!
1. The minimum phase argument may be attractive for people that really like measurements, but I personally don't care for it because it disagrees so much with experiment/experience. If FR really were so important, you could equalise any artifact free in-ear to sound like any high-end headphone by just measuring both products at the eardrum. This is obviously complete nonsense, because our hearing is not just a FFT measurement device, but for instance is sensitive to acoustic occlusion/openness as well, which influences our perception of headphone sound but is not directly measured in the FR. Other factors that are self evidently important are clarity (THD), driver size & angling, damping factor, linearity of the motor, etc.. My personal belief is that you can not bring back inherent brilliance due to transducer weight for instance, which you would see for instance in the FR, but could also be "sneaked in" with equalisation.
At the end of the day you can make up as many theories as you want, but if they disagree with experiment, they're not worth a lot.
2. I agree, but keep in mind this is just personal opinion. The HE 1 has stiffer stators, which directly correlates with better THD performance, which is to our knowledge the best in the world and practically unmeasurable in the vocal range. The amplification is also up to 4 or 5 times as powerful in the HE 1, so there are arguments why it would be the superior device. The HE 90 on the other hand has more acoustically transparent stators, so the relation between the size of the openings to the "crosspieces" in the honey comb grid is more favourable for acoustic transmission. In effect this means the headphones are more open and have more high frequency amplitude. To me this combination of brilliance and clarity is unique, and I haven't heard it in any other headphones
3. I don't think there is much sense in providing the schematics to let other people build alternative power sources. The amplification is built directly into the headphones, so you really only get a signal, polarisation voltage and power supply out of the marble block. Maybe we can do it down the line, but please keep in mind that you would only be able to exchange the pre-amplification.
I don't know the tube specifications by heart, only that it's 4 802 tubes for voltage amplification of the signal and 4 803 tubes for current amplification. They're a new production run of the old Telefunken equivalents, but I'll try to find the exact specifications and send them to you.
Kind regards,
Jermo
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