[Head Injury]

  I got my DT 990's. They have quite a reputation of being sibilant. I have used them for around 25 hours. They sounded quite harsh out of the box and still sound almost the same. I don't know much about sibilance. But I am having a hard time listening to vocals with them. Even my Grados don't sound this harsh.
They have hiss around bright sounds. The female vocals are more affected . 
It's like the vocals don't have any warmth at all.
For example - Above and beyond - On a good day acoustic version(2014) and Satellite(2014) are almost unlistenable with the DT 990's.
The vocals sound very dry and "hissy". Is this sibilance or something else?

Try EQing down around 6-7 kHz, this region can be associated with sibilance and harshness and the DT990 has a peak there according to Headroom's graphs. Lower it as much as you feel comfortable.
 
You can also EQ up the midrange around 500-3000 Hz, the DT990 has something of a "V-shaped" sound, and the midrange is a little recessed compared to the treble and bass hump.

 

[zanox]

 
Try EQing down around 6-7 kHz, this region can be associated with sibilance and harshness and the DT990 has a peak there according to Headroom's graphs. Lower it as much as you feel comfortable.
 
You can also EQ up the midrange around 500-3000 Hz, the DT990 has something of a "V-shaped" sound, and the midrange is a little recessed compared to the treble and bass hump.

I don't like to EQ. I read it distorts the sound in the long run. I will give them some more time. But is this what sibilance sounds like?

 

[bigshot]

EQ doesn't distort sound if you use a good equalizer. I've used lots of them, and the only one I've found that really doesn't work is the iTunes equalizer. The one built into my Yamaha AV receiver is totally clean and very versatile.
 
Sibilance is a spike in the frequency response in the most sensitive range of human hearing. Equalization is the only way to fix it that I know of. If there is sibilance, odds are there are response imbalances elsewhere in the audible spectrum too.

 

[castleofargh]

 

 
Try EQing down around 6-7 kHz, this region can be associated with sibilance and harshness and the DT990 has a peak there according to Headroom's graphs. Lower it as much as you feel comfortable.
 
You can also EQ up the midrange around 500-3000 Hz, the DT990 has something of a "V-shaped" sound, and the midrange is a little recessed compared to the treble and bass hump.

I don't like to EQ. I read it distorts the sound in the long run. I will give them some more time. But is this what sibilance sounds like?

what we call sibilance are those "sss" and "tss" sounds that annoys us. you most likely notice them on voices and maybe cymbals.
about EQ, yes it alters the signal, just like anything alters the signal, even the way some resistor is soldered, even a cable will in some measurable way alter the signal. what matters is the magnitude of things. many stuff we need to live are lethal in certain quantities. it does matter to learn about quantity and not just reject things on principle.
also there exist several sorts of EQs with many levels of quality.
in your case, you're having a hard time with some frequencies, meaning that the problem compared to the signal is at 100% of the value.
and you won't use some EQ that might reduce that problem or simply eliminate it, because you're afraid of something that might happen at -70db below music. the distortion form an EQ is most likely in proportion to the use of it, so obviously if you try to alter a short frequency range by 25db it's troublesome. but for 2 or 3db attenuation I would be very surprised if you could hear anything apart from the signature change itself.
 
I would have suggested a compressor DSP focused on frequencies where the voices are, but if you don't want an EQ, I guess a compressor isn't you're idea of a solution ^_^. for information almost 100% of voices on a record go though a compressor already, so it's not something as evil as it might seem.

 
ultimately if you don't feel comfortable with the signature, you might just want to get another headphone.

 

[limpidglitch]

Strictly speaking sibilance is a phonetic term. It's the group of sounds you can make by directing a sharp stream of air over your tongue and through your clenched teeth, like sss and shh as Castle mentions.
More generally on these forums it applies to any sound that to a significant degree corresponds to one of the main resonances of your ear canal, and therefore feels extra displeasing. As our ears are all unequal we also have different dominant resonances, this is why there is no better way to solve this than for you to play around with a parametric equalizer trying to place a few narrow valleys in the 3k-8k range. Claims that EQ is inherently bad is abject non-sense. Better to leave those naïve audiophile myths sooner rather than later. 
 
The use of a compressor that Castle also mentions, is called 'de-essing' in the studio trade, and is indeed common practice.

 

[zanox]

I see. I might eq it.
I am experiencing not only hissing but vocals have this grainy texture that sounds harsh. Does that come with sibilance?

 

[bigshot]

That indicates that the imbalance might not be narrow. There may be a wide imbalance centered right over the top end of the vocals, or there may be one or more separate spikes all in that range.

 

[zanox]

  That indicates that the imbalance might not be narrow. There may be a wide imbalance centered right over the top end of the vocals, or there may be one or more separate spikes all in that range.

 
Are my headphones faulty?or that's how the DT 990 supposed to sound? Have you tried the DT 990 PRO?

 

[Head Injury]

   
Are my headphones faulty?or that's how the DT 990 supposed to sound? Have you tried the DT 990 PRO?

It's how the headphones are, they're known to be very bright, and they have peaks where sibilance usually is. No headphone's perfect, the best sound will come when you find one you like despite its flaws then fix what you can with EQ. It's a tool, don't be afraid to use it.
 
Like the others have said, one's sensitivity to peaks like this will depend on their ears, how they're used to hearing the world. What sounds correct, flat, to one person isn't the same for everyone else. Maybe you're especially sensitive to frequencies where the DT990 has peaks, or maybe you're just not used to having an emphasis there. Can't hurt to try to fix it either way.

 

[SilverEars]

Try these
 

 

 

[bigshot]

neither of those charts indicate any emphasis of the frequencies that cause sibilance.

 

[limpidglitch]

  Try these
 
[pic]
 
[pic]
 
 

 
Be careful with comparing graphs from different sources. All sorts of confounding variables might make it a nearly meaningless exercise.
 
Here's the same headphones compared, all measured following the same methodology.
 

 
As to wether the DT990's are flawed, or are designed to sound that way, I'd say the two questions aren't necessarily mutually exclusive

 

[zanox]

   
Be careful with comparing graphs from different sources. All sorts of confounding variables might make it a nearly meaningless exercise.
 
Here's the same headphones compared, all measured following the same methodology.
 

 
As to wether the DT990's are flawed, or are designed to sound that way, I'd say the two questions aren't necessarily mutually exclusive

 
They still sound harsh after 40+ hours burn in. The artifacts or whatever in vocals pop up more and sound extremely bright with this harsh bright coating around the sound if that makes sense.

 

[zanox]

I have Grados which are bright as well, but with them, vocals sound smooth without those artifacts popping up more and making them sound harsh.

 

[limpidglitch]

Grado's are in some ways even more badly behaved than the DT990, but while the DT990 has that big solitary spike at 9k, Grados has a lot of smaller bumps all over the vocal area of the spectrum, which might make it sound perceptually more even.
 
The problem with the DT990 isn't really the spike, all headphones have deviances from ideal, it's more the 10dB difference between 5kHz and 9kHz that's the problem. If you manage to even out that difference using EQ, and add some compensation for your own ears, you should expect a marked change for the better.
 
Burn-in has also been discussed a lot here, and Tyll Hertsens did an interesting test a while back. The consensus from that seems to be that any change that occurs, happens very early on (the driver 'settles' more than it is 'burned in'), and the magnitude of that change, insofar as it occurs, is so little as to be practically insignificant. The simple act of reposition the headphones on your head will cause larger changes in how the headphones sound.