"Scott Dorsey" wrote in message
Laurence Payne wrote:
On 24 Aug 2009 10:52:05 -0400, (Scott
Dorsey) wrote:
The sort of reasoning that puts spikes on speakers but
doesn't really know why. Some say it's to "couple".
Others to "decouple". What do you think they're for?
You can do either... you can couple the speaker to a
huge mass, or you can decouple it from all (possibly
resonant) masses. Either method works, and you can
measure whether it's working or not (or you can just
put your hand on the floor and feel if it's vibrating).
Reading at face value, that reply states that spikes
either couple or decouple the speaker from what it's
standing on. Depending on which you WANTED them to do.
This can't be right. What DID you mean?
It depends on what you do with the spikes and where you
place them. The original intention was to couple the
speaker through a carpet to a solid floor, so the floor
and the speaker move as a system. But they can also be
used with a flexible material like a rubber pad to
decouple the speakers from the floor. --scott
I've ever heard spike claimed to be the mechanical equivalent of diodes...
....but audiophools say a lot of crazy things.
Driver moving mass is usually much less than 100 grams, but can be a 400
grams for some low-efficiency subwoofers. If the woofer is attached to a
substantial cabinet, the actual motion of the speaker enclosure due to cone
motion will be highly damped by simple mass loading to the point where the
energy thus radiated is trivial.
In general, the vibrations radiated by the cone are by far the most
important effect of the speaker, which is according to the basic design. ;-)
The proof of the pudding is to suspend the speaker in the almost same
location by means of fishline suspended from the ceiling which gives a very
strong decoupling effect. In actual tests, the speaker sounds the same.