Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Ineffective against bass frequencies

Works well for higher frequencies since it gives the sound of rushing air but I already had a fan for that. It's completely ineffective against what was and is keeping me awake, bass frequencies like helicopters flying over, large trucks from nearby construction, footsteps on the ceiling, etc. If there's a product that produces a constantly, low bass tone I'd love to buy it.