Frequency is measured in hertz (Hz). A person who has hearing within the normal range can hear sounds that have frequencies between 20 and 20,000 Hz. The most important sounds we hear every day are in the 250 to 6,000 Hz range.
An issue date was added, and cheques may not be valid a certain amount of time after issue. In the US and Canada a cheque is typically valid for six months after the date of issue, after which it is a stale-dated cheque, but this depends on where the cheque is drawn; in Australia this is typically fifteen months.
1 Answer 1. active oldest votes. up vote 6 down vote. I found an article that discusses this subject. It seems that the length of time before a check expires depends on the state and the bank: Discussions about personal check expiration dates inevitably spiral into debates about the nuances of loan ethics. Although banking laws differ from state to state, most states consider that checks in excess of 6 months old are considered âstale dated.â