I know I'll be bringing up an old thread but I just finished my fostex t50rp mod and hopping to sent it to frans at some point for measurement and have a filter made.
Here is a build log of my fostex t50rp.. I'm still tweaking the sound just a tad but it's near perfect now.
I wanted to make new mini xlr plugs in the cups so away with the old jack plug and the plastic mount that it was held by
Front of the baffle where all the felt is going to be taken away
Here I covered up the holes for the jack and the wiering with some electrical tape
This is what I used to close the holes
As seen here in the picture
The result when it was dryed
It needed a bit of repair to be even so I put on some more on the outer side
Later on I will be sanding them down and paint them but for now it was enough
I moved to the ear side of the baffle and removed the felt there the felt was first removed with a knife and then sanded down to be smooth
I then made a template if paper and cut out some paxmate for the ear side of the baffle
Arround the paxmate I wanted some dynamat
Time to solder some wire to the mini xlr
Here glued in place
Here the result from outside
And here inside the cup where I have put paxmate into the cup wells and self adhesive felt in the middle
I then got an idea that I wanted to make a grid holding down the felt on the back side of the driver instead if taping it in there here was one of the templates I made
Here is a rough prototype I made out of 5 layer laminated 2,5mm wood
Here is the final grid beside the prototype and driver
I then made some threads in the holes for screws to hold down the grid
And here is the final result with I felt installed under it yet
Placed a treble reflector on the Center grid I'm still toying with the size of this to get the right amount of treble and also filled the baffle with something called unigum that is used as a sealant in plumbing
I worked with several different types of felt and several layers and ended up with one layer of this white felt that I got from BMF the cut could have been nicer
I'll get to that at some point
I noticed the headphones had a box like sound and played around with different stuff and found this to work well with paxmate stribes in the cups
I needed to dampen the bass a bit as I don't use a bass vent right now ( I got plans on making an adjustable one ) so I put in this synthetic cutton that I got from a friend it's we're airy and down draw moist from the air and collapse like cutton balls
I made sure not to have to much I front of the driver
A piece if felt cut to cover the dynamat for Aesthetics reason
Lastly I put on some alpha pads for awsome sound
And then to listen for a while with my aune x1s dac and project ember
I know I will be doing some fine tuning on the sound.. I wanna find out how to get more soundstage and room out of them as they can be a tad congested compared to he500 but that's all the fun to try and find this stuff out