[Folex]

I recently transplanted 53mm drivers into a previous 30mm headphone housing. They are completely open and sound amazing. The only issue I have is after 20 minutes my left ear begins to feel fatigue. The drivers had prob 60/40 solder on them to start and I didn't realize this at the time as I tried to use 4% silver solder with it. Needless to say it didn't want work. But somehow I got it to work and its now extremely strong. After every solder I tug on the wire hard 10 times to make sure there is no cold solders. The mesh I used was very weak and has ripples in them from where my fingers had pushed them in. Both drivers are flush against headphone housing so I doubt there is different angles. I've never tried to transplant a driver before or really any major headphone mods. Any idea why the left side is causing fatigue and the right isn't ?