L1® Compact Table Top Mode

Question

To my knowledge, this is the first time Bose has suggested we place a bass enclosure on a table (for certain applications). It seems to me this would reduce bass response (no reflecting surface, like a floor) and invite the table itself to vibrate at certain frequencies. Source: Bose Guy in Calgary

Answer

On the subject of bass performance, a bass box can under certain conditions, create undesirable cancellations (dropouts) at certain frequencies, because of interference between the bass box and it's mirror image from a nearby boundary.

In the worst case, if you put a bass box outdoors, 1/4 wavelength above the ground, then climbed a ladder so your ears were over the bass box, you would be on the line connecting the bass box and it's mirror image and at a frequency equivalent to a 1/4 wavelength distance between box and ground, there would be a deep notch in the response.

However, if you were instead on the ground (not on a ladder) and so were roughly equal distance from the box and it's mirror image there would be no harmful cancellation.

That's roughly what to expect when you put the L1 Compact on a table: listeners are on the ground plane and therefore are roughly equal distance from the speaker and its mirror image, and therefore should not hear a dropout of bass.

We did a lot of experimentation and we're confident that the L1 Compact sounds really good in tabletop mode.

On the subject of table vibration, I think the only thing to be concerned about there is something rattling or audible vibrating. So far, that hasn't happened to me, but if it did, and I couldn't deaden the vibration I'd have to move the L1 Compact, or as suggested, use it on the floor in extended position.

Ken

Source: Ken-at-Bose

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