Nondirectional & Inaudible Bass: What Frequencies?

I don't doubt that Allison did something like that as he was always playing with / taking into account room loading and gain. There have been other designs that fire the woofer upwards into a "loading plate", which achieves the same effect without causing the spider ( part of a speakers' suspension ) to sag quite as much. Obviously, it is just another variation on a somewhat common design. As such, it has trade-offs of its' own to deal with. Sean
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Sean, I believe Dunlavy had models with both up firing and down firing woofers.

You might be right. I think that the first commercially available "loaded" woofer system was the Janus made by Jan Marovskis. That is, as far as i can remember.

Design Acoustics, a division of Audio Technica, also did this on some of their models. These were probably the most commercially succesful down-firing or "loaded" speakers that i recall. I personally think that DA took this approach primarily for space saving reasons, but they really weren't bad sounding speakers for the price and era. Sean
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