James Harris wrote:

Any ideas?

Widening the net a little....

Spikes is a concept that seems woefully short of merit, while vibration
absorbers is known and described in the literature as efficient in terms of
reducing midrange coloration via secondary radiation from the floor.
Literature reference: accellerometer measuments made by Arne E. Jensen on
his 4433 and the floor they were located on and published in the danish
magazine High Fidelity around 1978 or so.

Poul Ladegaard took this a step further by demonstrating the additional
advantage in decoupling the (midrange) loudspeaker unit from the front
panel.

It would be most interestering if the spikists have similar accellorometer
measurements that document the advantage of spikes.

James

Kind regards

Peter Larsen

On Mon, 24 Aug 2009 17:07:49 +0100, "Keith G"
wrote:

(I remember once I got someone to listen with his eyes shut while I slowly
rotated one speaker until it was facing the wall - he had no idea what was
going on and said the sound was unaffected throughout!! ;-)

Yes, the Critical Distance for a given room/speaker combination is
often closer than you think! In PA applications sometimes it's
practically impossible to place the audience inside it.

Where's your hi-fi listening "sweet spot" in relation to the CD? In
any given room, the same for all speakers or not? When recording, I'm
used to monitoring well inside, but checking a mix from WAY outside -
like in the next room with the door shut!

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
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

GregS wrote:
Another thing, if the floor is vibrating from the air vibrations, and
the speaker is still, the floor will make the speaker shake.

Yes.
But if the floor is vibrating from the air vibrations, you have a more
serious problem than that. A common one, but serious nevertheless.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

On 24 Aug 2009 12:33:37 -0400, (Scott Dorsey) wrote:

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.

In the second case, why spikes? Why not just the rubber pad?

David Looser wrote:
"Laurence Payne" wrote in message

My practical experience of large speakers - some much larger than
anything found in a domestic setup - is that they generally sound MUCH
better mounted at least a small distance away from any flat surface,
wall or floor.

At one time there was a fad for mounting speakers as far into room corners
as possible. My granddad, who was something of a "HiFi" enthusiast in the
1950s built a speaker cabinet which used the walls and floor as part of the
cabinet. I seem to remember that a barrow-load of sand was part of it as
well.

The corner horn had some advantages: first of all it meant that you could
take advantage of the edge effects of the corner to provide increased bass
response, and secondly that bass boost was predictable because everyone would
put the speaker in the same place in every room, rather than have it an
unknown distance from the rear and side walls.

It made sense back in the fifties when loaded horns were essential for high
efficiency at low frequencies, in an era of low amplifier power. Back then,
systems were mono and so the inability to place the speaker for good imaging
was a non-issue.

When stereo came in, corner horns went away.
--scott


--
"C'est un Nagra. C'est suisse, et tres, tres precis."

In article ,
Laurence Payne wrote:
On 24 Aug 2009 12:33:37 -0400, (Scott Dorsey) wrote:

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.

In the second case, why spikes? Why not just the rubber pad?

You want to minimize the area of contact with the pad. Plenty of more
efficient ways to do that than spikes, mind you, but spikes are usually
what people have handy.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

"Scott Dorsey" wrote in message
...
David Looser wrote:
"Laurence Payne" wrote in message

My practical experience of large speakers - some much larger than
anything found in a domestic setup - is that they generally sound MUCH
better mounted at least a small distance away from any flat surface,
wall or floor.

At one time there was a fad for mounting speakers as far into room corners
as possible. My granddad, who was something of a "HiFi" enthusiast in the
1950s built a speaker cabinet which used the walls and floor as part of
the
cabinet. I seem to remember that a barrow-load of sand was part of it as
well.

The corner horn had some advantages: first of all it meant that you could
take advantage of the edge effects of the corner to provide increased bass
response, and secondly that bass boost was predictable because everyone
would
put the speaker in the same place in every room, rather than have it an
unknown distance from the rear and side walls.

It made sense back in the fifties when loaded horns were essential for
high
efficiency at low frequencies, in an era of low amplifier power. Back
then,
systems were mono and so the inability to place the speaker for good
imaging
was a non-issue.

When stereo came in, corner horns went away.

It wasn't a horn, it was a bass-reflex.

David.

David Looser wrote:

When stereo came in, corner horns went away.

It wasn't a horn, it was a bass-reflex.

There's a lot less benefit in putting a bass-reflex design in a corner,
but you do still get that edge effect and the matter of consistency.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

"Scott Dorsey" wrote in message
...
David Looser wrote:

When stereo came in, corner horns went away.

It wasn't a horn, it was a bass-reflex.

There's a lot less benefit in putting a bass-reflex design in a corner,
but you do still get that edge effect and the matter of consistency.

I don't buy this "consistency" notion. There are still far too many
diferences: room size, furnishings and building construction. And that's
before we think about differences in the speakers themselves: driver types
and sizes, materials used, construction techniques etc.

David.