You will often see a sharp peak around 8kHz on these graphs. This is usually an artifact of the measurement tool (resonance) rather than the IEM itself.
Graphs show how an IEM performs in a metal tube. Your own ear canal shape and the tips you use will slightly change the actual sound you hear. 🚀 The "Tuned with Squiglink" Program squilink
You can select an IEM you own and a "Target Curve" (like the Harman Target ) or even another IEM you want to emulate. You will often see a sharp peak around 8kHz on these graphs