Beyerdynamic Tesla T1 dampening mod

[archigius]

My T1 is one of my favorite headphones ever.
I like the Beyer sound signature (also own the fantastic DT 880/600 ohm and the DT 1350).
 
But when i watched some photos of the disassembled headphone, i noticed that the T1 has no dampening material, only plastic.
 
This is different from the DT880/600 ohm which uses the same semi-open technology but has the dampening inside.
 
So i decided to try how to dampen the inner cup could affect the sound.
 
In the beginning this was just a curiosity, but after the mod i noticed that the headphone a had slightly warmer sound, which i like
(i usually like overall neutral headphone with a slight warm timbre).
 
So i decided to share this mod. Actually my T1 are modded and i think I'll keep them modded.
OK, let's start.
 
 
For this mod  you need some adhesive felt, small scissors, a small screwdriver, a pencil and some paper.
 
First thing is to draw on the paper 2 circles, the outer with a diameter of about 6.4 mm and the inner with a diameter of 2.5 mm, then cut them from the paper with the scissors

 
After this you have to copy the cutted circles on the back of the adhesive felt, using the previews draw to help yourself:
 

 
Once you've done, cut the felt with the scissors:
 

 
 
This is the final result:
 

 
 
Now we have to open the headphone. Please be very careful when you do this, the T1 is well built but you need to add an extra care, is always a 900 euro headphone. First remove the pads: gently pull away them and they will come away without problems
 

 
Then with the screwdriver remove the plastic ring which holds the driver in place. You have to gently pry on the ear cups to remove the ring.
 

 
Done!
 

 
Now you can remove the driver. Rotate the headphone with the external part of the ear cup upward, put the other hand on the inner part of the ear cup to gather the driver; when the plastic circle is removed, it should come off itself, if it does not, slightly move sideways the ear cups, always with the hand ready to gather the driver.
 
When you've done, you'll see this:
 

 
 
Notice the absence of dampening material.
 
Now you can simply put the felt in place and close the headphone
 

 
When you close the T1 pay attention that the plastic ring has a precise shape, you have the small protruding plastic piece in right place OR it won't close:
 

 
About the sound:
 
the differences with this mod are not night and day and I'm still experimenting them, but to my ears the sound is warmer, fuller, smoother; the bass has more impact and the male voices seems deeper than before; the hights are very slighlty decreased, soundstage is the same.
 
I'm curious to hear your impressions, if somebody decides to try the mod.
 
This mod is 100% removable and the headphone can be restored to original condition, without any problem.
 
 
 
 

 

[rhythmdevils]

Very cool.  If I had a T1 I would do the same.  I was shocked to see a semi-open headphone without any damping whatsoever that sells for over 1k.  I have a hard time believing that empty chamber behind the driver was an engineering choice rather than just a lack of engineering.  You can try foam, and different felts, every felt has a different sound.  100% wool is said to be the best acoustically.  If you use felt that has no adhesive back you can hold it in place with some open cell foam.  Nice work!
 
It would be really cool to see measurements by Tyll or Purrin comparing it to stock... 

 

[MrQ]

They weren't joking when they said 'semi-open'.
 

 
Makes you wonder though why they didn't mirror the radiating openings on the inner cup on the outer cup? So the soundwaves would follow a more natural path.

 

[Graphicism]

Quote:

This is different from the DT880/600 ohm which uses the same semi-open technology but has the dampening inside.
 

Ergo the DT880 is the better phone, the T1, a marketing fad. 

 

[archigius]

Quote:

Ergo the DT880 is the better phone, the T1, a marketing fad. 

The DT880/600 ohm is really great, but not that good.

 

 

[MrQ]

Quote:

Ergo the DT880 is the better phone, the T1, a marketing fad. 

Behave.

 

[Wapiti]

Excellent, clear instructions, archigius.
 
Thanks

 

[MacedonianHero]

Quote:

Ergo the DT880 is the better phone, the T1, a marketing fad. 

Ergo...keep dreaming.

 

[Graphicism]

When a piece of felt improves a $1300 headphone I call shenanigans to the so called 'flag ship' headphones and put them in the same category as cables and power cords.
 
I will however admit the T1 is a nice sidestep.

 

[Kernmac]

 
Quote:

When a piece of felt improves a $1300 headphone I call shenanigans to the so called 'flag ship' headphones

I call subjective opinion (and third party at that).  The felt dampening may or may not change the sound, this alleged sound change may or may not be an improvement.  People believe what they want to believe.  Don't call "improvement" just because someone (3rd party) thinks it might be.    To speculate that because the T1 doesn't have dampening in the cup that it is somehow inferior engineered-  that's shenanigans.
 

 

[archigius]

The point is not if the T1, HD800 and friends are worth 1000 euros or not.
 
I've heard the HD800, the RS-1 and even the Stax Omega, for me no of these headphones is well priced, they should cost considerably less.
 
The point is if somebody wants to try this mod and share his experience about the sound.
 
Actually i think the sound gets fuller and smoother, so for me it's an improvement.

 

[drummerman]

Two types of Standing Waves affect speakers mostly; Axial and tangential.
 
Axial denotes two parallel walls, tangential has four.
 
Now, looking at common Headphone cups, they are round in circumference and many have a rounded rear wall too. Even if only slightly so it should be enough to prevent most sound degradation due to internal waves.
 
Applying damping to cups will most certainly contribute towards a minute reduction of cup vibration at certain frequencies. These vibrations or 'hot points' of the spectrum will almost certainly vary with cup material, shape, size. It will be most difficult to find a general concensus on what material will work best (if at all) and where to apply them.
 
Personally, I would assume that a stiff cross brace is more efficient than felt or other similar materials and more important than standing wave reduction in typical headphones.. This is commonly acknowledged and used in loudspeaker design though there are some (though few) exceptions such as Spendors thin wall damping.
 
Thinly applied internal damping material such as cotton wool could be benefitial too but I wouldn't go overboard with it.
 
The best you can hope for is a correctly implemented, solid (non-vibrating) enclosure which applies the correct damping to the driver-diaphram. The rest is due to the driver quality (or lack of it).
 
As always, my opinion only
 
regards

 

[archigius]

Quote:

 
Personally, I would assume that a stiff cross brace is more efficient than felt or other similar materials and more important than standing wave reduction in typical headphones..

What you mean with "stiff cross brace"?
 

 

[drummerman]

Archigius
 
I would have thought a horizontal or vertical cross brace, applied unevenly to the cups ie. not at exactly equally measured points, perhaps further stiffened by an adjoining brace towards the rear centre (or around it) would dampen any driver induced vibrations (as opposed to standing waves) most universally. That and some for of driver baffle 'isolation' from the rest of the cup via rubber decoupling or similar.
 
An interesting example of vibration reduction by means of solid 'bracing' (in this case, 2 metal instruments applied to each cup from the outside, under measurement) can be seen in Dave Rat's headphone quest. I can't exactly re-call the particular model but doing the same with fingers had no or little effect.
 
This whole modding issue is a complex one, not least because there are so many different varieties of HP's, materials etc but certain fundamentals apply to Headphones as much as they do to speakers.
 
To give a quality driver the best chance of performing as intended, a stiff chassis is probably the best start, at least it wont do any harm. I am dubious when manufacturers introduce cup materials such as wood and state their unique reverb/vibration characteristics contribute to the sound. Imho, an enclosure has no place in contributing anything to sound. Less distortion (of any kind)  generally equals more accuracy though whether that is in line with your (anybodys) musical preference is another question though surely the aim of a speaker is to reproduce as accurate as possible.
 
That is where a company like sennheiser are very competent. Leaving aside for a moment whether the sound of different models appeal, they are supremely efficient at 'tuning' their headphones, often achieving different 'signatures' with similar drivers but varying the driver damping. - I have little doubt that their 800 series headphone has the best and most inert casing/chassis of any of their products.
 
I am sure many will disagree with me and I would not like to tell anyone they are 'wrong' per se. I am just trying to rationalize good design in the first place is important.
 
regards
 
 
 
 

 

[Graphicism]

Quote:

The point is not if the T1, HD800 and friends are worth 1000 euros or not.
 
I've heard the HD800, the RS-1 and even the Stax Omega, for me no of these headphones is well priced, they should cost considerably less.
 
The point is if somebody wants to try this mod and share his experience about the sound.
 
Actually i think the sound gets fuller and smoother, so for me it's an improvement.

You're probably right. I didn't like the T1 when I spent a couple hours with it a few months back, the sound seemed artificial in comparison to the DT880 which is my neutral. Personally I found the T1 to be closer to a theatrical or cinematic presentation than an accurate one, dare I say a fun-colored phone compared to a boring-neutral phone like the DT880. Knowing how quickly all the headphone manufacturers jumped on the same bandwagon with these 'flag-ships' I will likely wait for round 2, let them correct some of these issues and see what they come out with. T1 with dampening might be an option, have you tried Dynamet and other material?