I was curious about the Vex Pro so I ordered it and it arrived today:
The stock tuning is too bright for me and has "timbre" issues. As stated by many, you need to remove the 8KHZ peak and increase 10KHZ. That already is a great base for further individual adjustments. I also removed the 16.5KHZ peak a bit and decreased the whole area around above 1KHZ, I don't like the borderlining on Crins preference curve. This is what I ended up:
The black curve is my target. After the EQ adjustments the IEM is incredible for its price point and also fixes the "timbre" issues which I honstely just see as an issue resulted by the FR. I was really surprised. Detail retrieval is above my expectations, bass has some texture to it, it is not a "one-note-bass". Soundstage is also good. I expected a neutral-boring sound representation looking at its tuning before, but it is really exciting. The fit is very very good for me (I have bigger ears), they also weight next to nothing. A steal for the price point if you can EQ.
For APO EQ:
Filter 2: ON PK Fc 1400.0 Hz Gain -0.5 dB Q 1.00
Filter 3: ON PK Fc 2500.0 Hz Gain -1 dB Q 0.50
Filter 4: ON PK Fc 5550.0 Hz Gain -0.5 dB Q 0.60
Filter 5: ON PK Fc 7400.0 Hz Gain -7.5 dB Q 3.00
Filter 6: ON PK Fc 9700.0 Hz Gain 2.5 dB Q 1.00
Filter 7: ON PK Fc 11000.0 Hz Gain 8.0 dB Q 3.00
Filter 8: ON PK Fc 15500.0 Hz Gain -4 dB Q 1.00