Here you go!! Compared to a stock phone, this mod makes them brighter and increases upper mids and treble, so its no longer overwhelmed by the bass. If you already find the FX33 too bright or harsh, you may not like this mod. If you find the FX33 muddy, bass-bloated or congested this might be a mod for you. Readers should also note that this mod is not-reversible.

First you have to pull off the foam tips. Just gently pull them off with your fingers. They slide off with a little tugging. Once the foam tips are off, grasp the gray rubber tube with some pliers and pull them off. They should pop right off with a swift tug. There is a little glue that holds the rubber tube in place. I think other members have used different methods to remove the gray tube. Please feel free to post other methods!!

Use a sharp x-acto knife and cut / scrape off the paper filter screen. You can see in this pic there is a perforated metal mesh screen protecting the driver. So the driver is still relatively protected without the paper.

So... thats half of the mod. Give it a try. At this point, slide the gray rubber tube back on, and slip the foam ear-piece back over it and give a listen. It should be a LOT brighter than before. I found the brightness harsh and piercing. So... its on to phase 2.

Next take an old earpad foam from a junk-can and cut a small cube shaped piece out of it. Roll it up and insert it into the sound tube. The foam helps to attenuate the highs, and keeps earwax out of the sound tube. You can experiment with different sizes of foam. With larger foam pieces, the foam is compressed more dense into the tube, and more highs will attenuate. It is a trial and error kind of thing. I ended up cutting 3 different sizes of foam and using one that was just a little larger than the inside diameter of the plastic sound tube.


Heres the little foam filter piece. I used an x-acto knife and sliced up a KSC75 earpad cushion. Just cut a little cube, scrunch/roll it up and shove it in the tube. You don't need to cut it into a cylinder shape.

Once the foam piece is securely snug inside the tube, slide the gray tube back over the sound tube and pull the slieve back onto the tube.

Its a pretty night and day difference IMHO. I was comparing them to my nieces unmodded FX33 and the difference was very noticeable, even for her (a non-audiophile). I told her to keep whichever phone she liked best. She chose the black one, more for its looks. Of course you can combine this with any of the tip-mods. I find the stock tips the most comfortable, so I just leave them alone.

Good Luck!! and happy modding.