Recorders	Microphones/Transducers	Bat detectors	Shock-mounts
	CompactFlash	Overview	Playback	Cables
	Hard-drive	Shotgun	Headphones	Protective cases
	R-DAT	Parabolic reflector	Speakers	Additional
	MiniDisc	Omni-directional	Amplifiers	Helpful Reads
	Analog	Uni-directional	Accessories	Vendors
		Infrasonic	Preamps	Inquiries
		Hydrophones

Occasionally the need arises to utilize non-amplified speakers in the field. Reasons include having to generate higher-than-normal sound pressure levels for very long distance coverage, or perhaps trying to broadcast very low frequency sounds. Both of these require substantial power (watts) and large drivers (speakers).

The best solution is found in the car stereo marketplace. Companies like Crutchfield offer a wide range of 12-volt DC powered amplifiers in both mono and dual channel configurations. Wattages range from roughly 40-300 watts per channel with offerings from industry-leading companies like Sony, Alpine, Rockford-Fosgate, Kenwood, and US Acoustics.