Yes I broke the her "felt" and she will never be the same.
But thru my use and abuse,
I turned her into the mature refined can she really is.
To make long story short, it's time to "control the hole"..
Here are the new design goal achievements:
1- larger/better pad fit replacement.
2- "tuned port" control over the mids
3- dampening control over the bass
4- increase perceptual sound stage
5- absorption of any high frequency standing waves on center of driver surface .
6 - full open hole ventilate the magnet structure.
7- Acoustic coupled ported design reduces turbulence, inner driver chamber pressure & distortion.
8- less typical "spherical" wavefront for more correct sound wave pattern to ear and thus better sound imaging.
Now for details:
The small size of driver is already a plus for better control, details and less driver breakup,
But the poor pad shape and cup angle design limits the types of ears which can hear the quality potential so we have to totally come with a new approach. .
First step is abolishment of stock pads..
I have tried a few even expensive Audio Technica leather pads, but for the Mikros90, the Sennheiser hd25 pads fit best .
This alone is only part of solution(for fit) and subsequent sonic modification solutions need to be done, because if anyone tried the Senn or any pads alone, the sound, is off because the Mikros90 relies on the stock pad's inner foam to preserve it's sound...
The approach here is not in just using existing material solutions,
The actual objective is to "harness" and modify the sound to our liking, from within.
To do so we must alter how the driver "sees" the "hole"...
We must "acoustically couple" the inside and outside wall of that hole ...
Think of how a trumpet is designed to interact with an open space. .
Now take out it's mouthpiece and try blowing again and notice how much less you can affect or interact with the outside.
Same applies with horn loaded speakers and "tuned port" speaker enclosures.
They help "couple" the two sides..
This is similar to how we will need to adress this sacred hole(!)..
We will make what amounts to the driver being "coupled" to the huge space it "sees" on other side of the hole...
Ok enough techno babble.
Time for mod..
Open the Mikros90...
Use two of the dense felt discs used normally for placing on furniture feet.
Use two per driver...
*pic*
Make a hole in center of them appropriately and slightly larger than the hole.
Cut the shape them smaller into a "donut" shape.
Attach one on top other, then attach them over/and around the sacred hole..
*pic*
Notice and realize that the left driver will need to be cut on a corner where the internal plug resides but don't worry the point is to have a "port" over the hole. .
*pic*
Circuit board area to be notched out in felt disc..
Ok
Now onto the large space in cup..
Place a thin strip of modeling clay or blue-tak along the upper edge of cup for damping any cup resonance. .
I used black modeling clay..
*pic*
Place a circular flat strip of corkdboard (found in most art stores)
Cork is one of most effective sound absorption materials.
The purpose here is not to modify the sound, only to absorb any reflecting sonic back waves.
Choice of any other material besides cork, here in the bottom of cup, (to absorb back waves) is ok.
*pic*
The modification of sonic tonality and signature will now commence,
by using the addition of dense felt material and specifically, "the amount" of felt material used to fill in the rest of the empty space...
More=brighter
Less= darker
So now mainly, it is actually what is filled now, in the empty space, that will change the tonality...
Not any "esoteric" materials of leather, etc, like in the past.
*pic*
For this I used my own very special material. ..
But you can use ANY dense cottony wool like material. .
My material happened to be much more dense than normal cotton and closer to the consistency of wool..
As it was My own Dogs matted hair!!!
Look (!)
*pic*
Haha no I am not insane,
It just coincidentally had the consistency I NEEDED so I used it..
Plus it was a relief to my dog for summer lol.
So We need dense damping in order to bring out the mids and upper mids to sound balanced with bass& trebles. ..
This is where each modder can adjust to his/her liking,
For a perfect solution to their preference!
Also making the felt Hole smaller is a solution for using less dense materials,
but I wanted to have more control of the sound..
Now carefully close up without breaking any wires while trying to get the screws in holes!
Still, we don't stop here.. (!)
Next onto soundstage!
FOR soundstage, we employ a solution similar to German company which shall not be named & that covers half it's driver.
This solution also smoothes the response as well as does what I stated in numbers 4,5&8 posted earlier top of this post...
Ok For this step we will need a bandage(!) And black electrical tape or colored painters tape (cosmetic covering).
Place the white fabric part of the bandage over half the speaker at this angle:
*pic*
Then cut the excess on each side which will be placed over center here:
*pic*
Now use black or colored painters tape to cover the bandaid. .
*pic*
Now place the nice black or more expensive blue Sennheiser HD25 pads on!
*pic*
There you have it my friends. ..
The Mikros90 Ultra mod.
*Pic*
I have settled on this mod for quite some time to be sure it's good enough.
Pad replacement also stands up well to daily abuse.
This is my most used can for portable use now..
EDIT! EDIT! EDIT! ::
DUE to the fact that the "soundtage" part of mod decreased the upper mids to trebles volume level , I decided to remove that untill I find a more suitable material. Probably a adhesive foam but regardless I think the sound is very dynamic and large already because of the larger pads/tuned port combo..