[Zombie_X]

Hi all,
 
I recently did a test with my DT990s. What I originally did was swap the Beyerdynamic Gel ear pads on. The DT990 gained a lot of bass, but has the really echo chamber sound to it (like it's echoing). The new bass was flabby and uncontrolled. I noticed while putting my hands over the grill the echo like sound disappeared and the bass tightened up considerably. So now I had a major brain storm: making the DT990 a closed back headphone!
 
What I did was swap the DT990 drivers into the DT770's body, leave the bass ports open, and add some felt with some acoustic fluff  and blu-tac to the inside of the cup. The results very very nice indeed! The DT990, while before only had a tad more bass than the DT880, now had a ton of bass and was better quality bass than the DT770/80Ohm Pro. I also fund the highs to be smoother sounding and the midrange to have been fleshed out more.
 
Now I found that you could also open up the DT990 cups and put some tape over the venter vent. I would recommend electrical tape for this. I would not do this wth stock pads as it really kills the sound of the headphones.
 
Let me know what you think!

 

[sugarkang]

How do you do this exactly?
Do you have a PDF guide or similar?

 

[Zombie_X]

I do not have a PDF guide but I will be taking pictures to show you guys how to do it.

 

[wdahm519]

Definitely take some pictures.  I won't be doing this because I'm in love with my DT990's and I wouldn't want to ruin them but I'd like to evaluate your approach.

 

[iHasCake]

subscribing 

 

[nickchen]

Implanting Beyer systems from their original open vincinity into a closed one (plus changing pads) has indeed some quite nice results. I'm personally also very fond of NoXter's closed back DT880'600. This one doesn't provide "a ton of bass" as described by Zombie here, but a bit more than stock. I also like the "collateral" effect that the mids section sounds a bit warmer. How does that 990 construct fare in that respect?

 

[EddieE]

I borrowed Nickchen's DT880/250 closed back and they were extremely fun with fantastic bass kick. The metaphor that came to my mind was the DT880 was a grown up headphone and the DT880/CB was the same headphones in its wilder teenage years. 

 
Subscribing to see what treasures the DT990 brings.

 

[RazorJack]

Looking forward to pictures!
As much as I love my DT990/600's, I really was used to the earcrushing DT770pro/80-kind of bass, because those were my primary set of cans for like a year. And in all fairness, with some types of music I actually still do prefer the 770pro, the kind of music that has loud mid- and upper bass but not much sub-bass (like Leftfield or The Orb).

 

[nickchen]

Quote:

I borrowed Nickchen's DT880/250 closed back and they were extremely fun with fantastic bass kick.

It was the 600 ohm version, the 250 ohm system isn't quite capable to deliver such a dry punch.

 

[EddieE]

Ah that makes sense, I remember you saying the 250ohm were average in bass kick but I didn't find them average at all, it was exceptional in that area.

 

[Zombie_X]

See the way I had done it gave me a bunch of bass. I'm working on the pictures now and will have them completed soon.... hopefully..
 
Quote:

Implanting Beyer systems from their original open vincinity into a closed one (plus changing pads) has indeed some quite nice results. I'm personally also very fond of NoXter's closed back DT880'600. This one doesn't provide "a ton of bass" as described by Zombie here, but a bit more than stock. I also like the "collateral" effect that the mids section sounds a bit warmer. How does that 990 construct fare in that respect?

 

[apatN]

Great, I remember you weren't too content with how the DT880CB sounds, right? Glad you found this!
 
And to all people who are afraid they will ruin their headphones with this mod... Let me tell you that would be hard. 

 Beyers are built like tanks and it is very easy to open them up, tape them closed and close them back up.
 
Zombie, what pads do you use with this? Can you comment on the difference between gel and DT770 pads?

 

[Zombie_X]

Hi guys,
 
I use the Gel pads on them as the stock DT770 pads make them sound bloated in the bass, very muffled, and congested sounding. With the Gel pads you still gets the highs (though s little tuned down), more midrange, and more bass. The only thing is that having them closed up makes them sound less airy and the soundstage becomes much smaller, but then the sound is more concentrated and in your face.
 
I find that using the DT990's stock housing and using the DT880 Closed Back mod on this headphone provides some good results.
 
What I have down is peal away the felt damping in the cups, tape the main vent whole closed (with electrical tape), put the felt back in and them wad up some cotton balls and put them over the vent hole you taped up. This way the headphone is semi-open and you will get some air to the sound.
 
The second method involves taping up the tiny vents that are under the felt ring. I put about 2 layers on each vent. This method will give you the most isolation and bass impact, but at the cost of air and soundstage. The soundstage does really collapse and becomes very upfront.

 

[Ultrainferno]

Don't forget those pictures Zombie
thanks in advance

 

[Zombie_X]

My camera is out for repair...again. So pictures may take a while to get up.