https://mynoise.net/noiseMachines.php https://mynoise.net/noiseMachines.php - "Noises, soundscapes and tonal drones ... Shaped to your hearing and environment"-

https://mynoise.net/noiseMachines.php https://mynoise.net/noiseMachines.php - "Noises, soundscapes and tonal drones ... Shaped to your hearing and environment"--great for improving focus, relaxing, etc.