Downmixing multi-channel audio signals to target channels by pre-downmixing frequency coefficients that are encoded using a most frequently used block type in stereo channels in the frequency domain, thereby reducing an amount of calculations and an amount of power required to downmix the multi-channel audio signals. A backwashable filter element containing a diffuser plate that is located within the filter member at the end where the backwash fluid enters the filter member and a number of filter stalks with each filter stalk including a diffuser rod is disclosed. The locking mechanism is provided for mechanically or magnetically released the attaching pin for detaching the tag body from the article. The HVAC system further includes an evaporator with a first portion in the front airflow path, a second portion in the rear airflow path, and a seal situated between the first portion and the second portion. The present invention also includes unitary sample preparation and detection devices to be used in accordance with the methods.