Sennheiser HD 820

The Gorilla Glass looks nice to me. I don't think of Gorilla Glass brand as anything special. I had it on a $100 no contract phone. Axel Grell talks about having a German company make the part for HD820 is expensive due to it's shape. Maybe it is.

Gorilla Glass did fine until I started cleaning the phone glass with moistened lens cleaner wipes (with alcohol) after cleaning my glasses. No problem for a while, then I noticed the glass disintegrating on one corner. I quit using the wipes but the disintegration continued. That lead to cracking to the point I had to replace that cheap phone. Gorilla Glass may be tough but it does not stand up to alcohol (which is in many glass cleaners).

 

Yields on curved glass are always low, though it's not nearly as bad with something the size of the HD820s window, or a "2.5d" front for a phone.

Still not great though, especially if their tolerances are anything to speak of.

IIRC, one pc case company that uses curved tempered glass panels said their yields are like, 1/3?

 

Yeah, photobucket is unreliable. Imgur is a better image hosting site.

 

There are likely different grades of Gorilla Glass, and the manufacturer of the $100 would have gotten the cheapest possible grade just so they could stick the brand name on their marketing materials.

 

Thinking in wave-lenghts of sound it is hard to believe that the shape of the glass can influence anything below, say, the two top octaves (at most). The typical "closed cavity resonances" would be much lower in frequency and would rather be determined by the volume of the cavity. One generally needs to put (ugly!) stuffing into such cavities to provide effective damping ( say, dynamat, as mentioned above by Maxx134), but in this case who would want to obscure the nice boutique appearance!
OTOH one can not exclude that- by help of the glass shape they have found
it possible to cancel out some nasty upper treble peak (6k?LOL) through
reflexion*. (pic your anti-poison).



*Incidentally it is only a few weeks since i managed to reduce the 4khz peak in my M1060 considerably by a comparable methode: By placing CD's on the outside, parallel to the membrane. The perfect distance in my case was 4cm. I plan to make a funny thread about it soon with funny pictures: CD
disks attached on each side by thin strings. Very futuristic and anti-boutique.

 

Sennheiser is capable of making this HD820 sound good.

When I was in Berlin, even with the HD800S I was careful when music had a treble peak. The HD700 was truly awful in that regard. Thing is, when even Jan Meier is still working on a solution for that treble peak of the HD700/800/800S well the Sennheiser engineers know something is still off.

Unless certain impressions and measurements here confirm that the HD820 does not have that treble peak, nothing Sennheiser says is to be believed. That is too bad really. I hope the HD820 will at least sound as good as Serious' modified HD800. I hope they improve the headphone...

 

Thanks, as you can see, yours as most HD800 CSD looks very good.

For our purposes, don't worry here about anything below 2k.

Above 2k we can see that there is a base/resonant around 5-6k region and some more (multipliers) above 10k..

This is usually not a big deal,
but it is the telltale sign of how the 800 creates it's diffuse effect to the soundstage.

Your decay is past 1.5ms on these areas also approach 2ms.
My CSD has none of them, and most decay is around .5ms

Only member Serious was close to mine at under 1ms for the base ringing.
but still showing the two ringing areas over 10khs (multipliers of base ringing),
And That is with his trebles lowered with both SBAF & SD mod simultaneously applied,
Which I personally found to sound reference but too tame .

I prefer the 800S sound so I retain the hallmark elevated treble air and also the 800s sound without its distortion.

So you see that damping material alone will not take away diffuse sound.
Only my dymamat mod killed it.
Yet there is something to be said of having the trademark diffuse soundstage for some genres like classical.
It adds that touch of airy haze where as without it you gain more pinpoint localization.

This is why I believe the change in the 820 frame will change this aspect.

Yes that's it..

Yes I have transferred most my pics and will update in coming week.

I believe they will have improvement,
because I myself found the stock 800 rear metal cage to add upper spectrum reflections,
which I perceived as added fatigue.
So that aspect will be gone with something else in it's place...

The concave glass, which is a different physical barrier further away and reflecting back to the frame...
Whether that is good or bad is unknown, but most probably will add to the sound regardless...

 

I'm pretty sure that wasn't the alcohol. It will f**k up any oleophobic coating, but won't dissolve your glass, I think. It was more likely to be small scratches and edge impacts that caused it to crack.

Incidentally, you don't need to use alcohol*, these do an amazing job, and last for ages:

https://www.amazon.com/3M-Microfiber-Lens-Cleaning-Cloth/dp/B007I5S0IY/

They're really good for camera lenses too, obviously.




* FOR THE LENSES. You may well choose to ingest different forms of alcohol still; let's not be hasty.

 

Another common ingredient in lens cleaning fluids, ammonia, will f**k up many common coatings, like some (most?) anti-reflective coatings and reflective coatings like iridium. I ruined a brand new $80.00 iridium faceshield and a $600 pair of glasses lenses this way. Beware.

 

The concern I have with the Gorilla Glass enclosure is that dust particles, moisture laden air, and pirspiration can collect on the inside surface. I suspect this will be a long term quality issue for HD 820 headphones that will eventually require repair/cleaning. It will be interesting to see how Sennheiser addresses this without it becoming a major point of frustration.

 

Good point! Just outgassing from the plastics may leave a bit of haze. Without cleaning, the glass may never be as clear as when brand new.

 

Perspiration getting to the glass?? Are you going to work out in these or wear them at the beach? I doubt that will be an issue....

 

You would think they would have designed it so the glass would be locked in with a couple of tiny removable screws so it could be accessed for periodical cleaning.

 

I understand your attempt at humor. However, even at normal resting core temperatures of 97.5-99.5° F the body regulates heat and makes physiological adjustments to maintain a constant temperature thereby increasing/decreasing sweat that is evaporated. The temperature of skin surrounded by or in contact with the headphone will be higher so the body will have more thermoregulation in the area of the headphone's ear cup. Dust particles and moisture laden air carrying oils will absolutely be visible as residue through the Gorilla Glass over the headphone's life. And to be clear, I am NOT referring to condensation forming on the Gorilla Glass during listening sessions-- that will not happen.

I design products for a living.

 

I really appreciate your reply...,and yes it was an attempt at some humor...but you really think that will be an issue? I don't....

 

Yes, it is inevitable. The unknowns are how long it will take to for debris and oils to collect on the Gorilla Glass based on the properties/construction of the materials and how the cup is assembled. We'll have answers to those questions once someone does the first teardown of the HD 820-- I'm sure it will be a member of SBAF to tackle it first.

 

This is only a cosmetic issue, as none of what is claimed will accumulate on the inside of the glass would, as far as I know, fail to accumulate on the inside of any other material at effectively the same rate. The only difference being that one can see it. If they are good enough to end up iconic, it might be seen as aesthetically pleasing like the "patina" on an old motorcycle, or fountain pen, or some such.

 

I hope people aren't expecting the concave glass thing to work miracles here. Glass is highly reflective and that volume behind the driver is far too small for the curve to have a very meaningful effect. It's akin to listening to OB speakers in a closet, putting a parabolic mirror behind them, and expecting great results. This is more of an aesthetic thing than anything - the window view of the driver is unique and looks really cool IMO. If Senn was concerned more with performance they'd stuff the cups with an absorptive material, but then that'd ruin the window look.

People should be more excited about the new pads, those will make a big difference. Also interested to see how well they do in Tyll's isolation measurements.

 

Or damping/absorbing material behind the driver cap? Then you'd have less for the glass to reflect.

 

Not for legit impressions, just for a better look at the headphone...