I have a pair that I'm planning to use with my homemade e-caller that came with a really awful generic computer that a friend bought a few years ago. The only marking on them is "Made in China" but they sound pretty good. They use four "C" batteries and you can get really volume out of them with a nice loud, clean source like a portable CD player. So far everything I'm getting together for the e-caller has been stuff I've found lying around and I've got zero invested to date. With the investment of buying a CD or two I could have a complete non-remote e-caller, but that misses the biggest benefit of having an e-caller, namely having myself in a different place than the noise is coming from. Now I'm stuck with trying to figure out the cheapest way to make it remote capable. If it comes to getting an Azden, it will probably be a while, a long while. I'm hoping to an AR lower (and maybe upper if I keep the honey-do list done enough to think I can pull it off) for myself for Christmas, and that may be it for shootin and hunting expenses for a long time. /ubbthreads/images/graemlins/frown.gif
I wish I could help you out more with a source for battery-powered speakers or at least tell you the brand, but there's not a mark on these things except for the "Made in China" and some molded marks around the volume knob. Most computer speakers are made to use with an AC adapter to change AC current to DC. You might try finding some cheap computer speakers that use a 6V AC adapter. Then you could snip off the adapter and wire one of those old 6V flashlight batteries to it. If you could find a set that used 9V instead of 6V, you could try wiring it to a little 9V battery. I don't know how long a little battery like that would last, though.