I too like hearing the threshold, those faint squeaks can turn into good signals after removing some sand. The last time out my headphones broke (JBL). I was using them temporarily until I decided on what to replace my original (lost) Koss phones with that came with the machine. I then had to switch to the speaker, never again. I instantly became a magnet to every person on the beach. That's when I thought of the silent search, unfortunately I was unfamiliar with it and ended just calling it a day. Those JBL's were a $150.00 pair of phones, the impedance at 32ohms match the Sov GT exactly. I could hear everything, the differential of the tones was amazing, targets became easily discernible. I got to where I knew what was coming up 90% of the time. Never had that level with the Koss phones. I ordered a pair of Jolly Rodger Ultimates (16ohms). I can only hope that they are as good as the JBL phones.