dt990 rattling, calling beyer experts :) - Page 3

...i don't understand your logic, on the contrary if at first it was only one driver then the other start rattling it should blow the amp theory out of the water...

Bushguy is right here - if it was a hair in left driver, it is going to stay in left no matter what you do. Good & quick check is to swap L and R channels on amp side. If after swap the right driver rattles - then the fault "travels" with the channel not with the driver - rendering theory of hair/foreign object in the driver useless. Does that make sense?

As a last resort I must conclude the one nut under the headband must be loose... Good luck obtaining the "special tool"

The DT990pro has a nut under the headband? When I took mine apart, it didn't have any nuts.....
Hm.............................. I'm confused

I was joking... Shahrose is the loose nut under his headband, was the joke

But seriously, I would suspect multiple hairs on both drivers or his amp clipping.....As has been said...

Oh my goodness, How did I miss that joke!!!!!

Well sure, for peace of mind, get it replaced under warranty...

Best of luck~

/And sorry Towert7, I'm tired and getting silly ;-}

I know this thread is a bit old, but this happened to a newly acquired pair of Darths. I guess it's really problematic esp. with DT770's in general.

Another solution and what worked for me, is actually getting to the guts of the thing, all the way to the transducer and taking a car of air to it. Angle it a bit side-ways and give it a good few puffs. Also keep a good distance, don't get too close as the air is pretty pressurized and may damage the driver, so just be careful of that. It worked like a charm for me. I was worried these new Darths were Kaput already

I've been doing a lot of pad rolling on my DT880s of recent... Once you've gotten this far, why not take a moment to listen to the cans without any earpads? I can tell you that the DT880s are mighty detailed like this. Unfortunately, they're not very comfortable and when you take them off the two sides bang together like cymbals but it's an interesting experience.

Ah! I’ve been having the exact same problem with my 990s for the last couple of months in the right hand side. I read this thread and took them apart (again) just to see if I could see a hair or something inside. I ended up taking them completely to bits, basically taking the drivers out of the larger white ring, stripping them totally down until the really thin driver film is exposed.
Playing music through them like this sounded fine, so I put them back in the protective metal mesh cover part, but the rattle returned. After much playing of different bass frequencies at different volumes with the driver in different positions, I came to the conclusion that the rattling happened when something was touching the thin film on the driver (equivalent of the speaker cone I guess). Basically, the metal dome protecting this had been pushed in at one point, so instead of being a dome outwards it was essentially a dome inwards. Hard to describe, if you look at the thing then it’s easy to see what I’m talking about. I popped this back outwards (easily, with one finger), and put the phones back together. They sound as sweet as ever now, thanks guys 
Anyone else having this same problem should definitely look at the metal grill part, or check if there is anything at all touching the cone. To get them apart as far as I did I had to take off the foam padding, the thin foam circles to expose the drivers, as in the photos. Then prise this ring out, and then prise the drivers out of the thicker white ring surrounding them (carefully cutting off the soft glue holding them together).
If anyone needs a hand, or doesn’t get what I’m talking about then reply here or PM me.
Many thanks, Mat.

I've just recently been getting a rattle in the left cup of my DT990 2005.
I opened up the left cup a couple of times and looked for hairs etc. as suggested, to no avail.

I finally noticed that giggling with the cable at the place where it enters the left cup would sometimes reduce the apparent driver rattle for a while.

Took the left cup apart again, and made sure that the small wires that come in and attach to the driver terminals were not crossed or touching each other.
If you push the cable into the cup, a metal cable cover will pop out allowing you to freely rorate the cable until the wires are as straight as possible. Just pull it back into the rubber grommet to secure again.

Problem solved - no more rattle effect in my left cup!
Looks like my rattle probably wasn't in the driver itself, but the small wires vibrating against each other. I can now enjoy my Infected Mushroom CD's again!

 

Had this problem five minutes ago and a year back.

 

The first time I just opened the cans and removed the hairs like described earlier. Actually had one of the elements die on me for a while however after blowing whit my mouth pressed against the element it thankfully started up again (this idea came out of desperation).