Abstract: Apparatus and method are disclosed for sustained delivery of a wide range of plant supplemental and treatment materials. The treatment materials are delivered to the plant in a non-aqueous gaseous phase.

Abstract: A loudspeaker system suitable for a confined space includes an electro-acoustic transducer and an enclosure for the electro-acoustic transducer. The enclosure combines a second order topology to produce a rising acoustic response (40) for the system at a second order rate and a helmholtz resonator adapted to modify the rate of rise of the response relative to the second order rate such that the response is attenuated relative to the second order rate but is accentuated relative to a flat response, within a substantial part of a passband of the system at least at a selected frequency or frequencies. The system has means included in an electrical path driving the electro-acoustic transducer for equalizing the rising response to provide extended dynamic headroom at least at the selected frequency or frequencies.