All lines will emit sound or vibration underwater especially when taught and moving fast, or when still and taught in heavy current. The amount of sound and/or vibration from you or your equipment above or below the waters surface in each circumstance depends largely on the type of line used. Coarse braids will sound or vibrate more so than Mono or Fluoro of the same dia. Smaller dia's emit a higher pitch than Larger dia's of the same type. How taught the line is and the amount of stretch in the line is also a big factor in transmitting the sound. I never worry a lot about fluoro and mono when in use unless flipping and pitching short distances, but Braid is another story. I use the smoothest braids I can find, Suffix original or Samurai, to reduce noise effect and especially in heavy grass, brush and wood. The sawing noise and vibrations are a REAL deterrent with heavily pressured fish. The quieter the surroundings and waters surface, especially when shallow, the more stealthy we should be. When flipping and pitching with heavier weights etc. I try to be careful not to set the reel on a taught line or during a vertical fall. When windy and deep, and/or in muddy or night conditions, if the bait, jig etc has touched down without a bite and after a brief pause, I'll tighten the line and lightly click my reel in and out of gear to create a bottom sound or disturbance to possibly draw a fish from afar. Just use your common sense and realize that anything that may alert the quarry of OUR presence is not necessarily a good thing
