The only bird known to make use of infrasound (at about 20 Hz) is the western capercaillie. The hearing range of birds is from below 50 Hz (infrasound) to around 12 kHz, with maximum sensitivity between 1 and 5 kHz. The range of frequencies at which birds call in an environment varies with the quality of habitat and the ambient sounds.
Get started now! 1  Commercial carpet cleaning costs between $.05 and $.20 per square foot. 2  You can rent Rug Doctor carpet cleaning machines for $25 to $40 for 24 hours from many locations. 3  You can buy carpet steam cleaners starting at around $150.
If we were to tell you that the average price per square foot for carpet cleaning pricing is $0.28 per square foot, it tells very little about the franchise that charges $0.35 per square foot for carpet cleaning or the carpet cleaning price of $0.15 that your mom and pop carpet cleaner may charge for the same service.arpet cleaning should be performed every 12 to 18 months. If this were the case, every carpet cleaner could charge $0.10 per square foot to clean, the carpet cleaner would be profitable, the consumer would be more satisfied with the results, carpet wear would be less, and fewer dissatisfaction complaints would result.