Generate a continuous, one-hour long brown noise track suitable for sleep and relaxation. The sound should be deep, consistent, and have a rumbling quality similar to a low roar, like the sound of a distant waterfall or a strong wind through thick foliage. The volume should be steady and soothing, without any sudden spikes or drops. The track should be loop-friendly, meaning it can be played on a loop without noticeable interruptions or variations. The tone should be warm and enveloping, creating an atmosphere conducive to deep sleep or meditation