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?

In article , 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?

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

greg

"Keith G" wrote


Note also the weight on top of the speaker cabinets - have a friend who
stacks books on top of his speakers to eradicate cabinet resonances and
will try to find a pic (I know I've got one somewhere),


OK, that wasn't actually too hard:

http://www.moirac.adsl24.co.uk/showntell/0002.JPG

Incidentally, those speakers are a pair of Cyburg's Needles I built and sent
to him over in Brussels. He loves them, but they ain't ever gonna sound any
good out in the room like in the pic - contrary to what someone said here
recently, they need to be flat back against a wall or other large, flat
surface for bass reinforcement....

.....when they will sound incredibly good with a crystal clear yet rich 'full
sound' which totally belies the little 2 inch, cheapo 'car speaker' Viston
drive units!!

(I got a pair here in constant use on this computer and the radio and they
are superb - people look for the subwoofer!! :-)

But enough of that - that's history now...

In article ,
Keith G wrote:
Note also the weight on top of the speaker cabinets - have a friend who
stacks books on top of his speakers to eradicate cabinet resonances and
will try to find a pic (I know I've got one somewhere), but whether or
not that really wotks isn't important: my reason for heaping things on
top of speakers is simply lack of space and the speaker tops are*
somewhere handy to put stuff!!

Since it's impossible to make a totally rigid speaker cabinet some makers
take into account any 'output' from the cabinet itself. Think the first to
do this was the Spendor BC1. Which was designed to be mounted on an open
stand about 9" high. Adding mass to the cabinet - like putting books on
top - would negate the design theory.

--
*If you try to fail, and succeed, which have you done?

Dave Plowman London SW
To e-mail, change noise into sound.

On Mon, 24 Aug 2009 15:59:17 +0100, "Keith G"
wrote:

Note the record deck sits (without suspension) in a massive plinth made from
kitchen worktop offcuts and sits on a two inch thick 'grano' paving slab
(painted black) on firm, rubber 'doorstop' feet. The 'hifi stand' with the
extra weight in it (valve amp and large SS power amp) is pretty firmly stuck
to the ground (concrete floor under weedy/cheapskate bedroom carpet) and I
can quite definitely say the sound from that deck has *by far* the best bass
and pin sharp clarity I have ever heard from any turntable!

(That said, the other tt I use atm is a simple Technics deck with 'squidgy
suspension' built-in and I like that one just as much!)

So what characteristics does the Technics have to compensate for its
*by far* inferior bass and clarity?

One deck is close to a speaker, another is actually on top of one! Of
course THOSE decks never feed THAT speaker?

Are the speakers you actually listen to cramped against walls and
other equipment in that way? Do they sound different/better given a
bit more space to work in?

In article , (GregS) wrote:
In article , 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?

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


Another thought, when the floor is vibrating, its likely not
to be in phase with the speaker output, and it will be frequency dependant.
At least this tend to stabilize the frequency slewing.

What am I talking about?? !!


greg

"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.

David.

"Dave Plowman (News)" wrote in message
...
In article ,
Keith G wrote:
Note also the weight on top of the speaker cabinets - have a friend who
stacks books on top of his speakers to eradicate cabinet resonances and
will try to find a pic (I know I've got one somewhere), but whether or
not that really wotks isn't important: my reason for heaping things on
top of speakers is simply lack of space and the speaker tops are*
somewhere handy to put stuff!!

Since it's impossible to make a totally rigid speaker cabinet some makers
take into account any 'output' from the cabinet itself. Think the first to
do this was the Spendor BC1. Which was designed to be mounted on an open
stand about 9" high. Adding mass to the cabinet - like putting books on
top - would negate the design theory.


The Rogers 'BBC Studio Monitors' I had here a while back were
'thinwall/resonating' types and sounded very good indeed, apart from the
rasping bass unit I couldn't cure - without spending a lot of money and
maybe changing the speakers characteristics too much, in any case....

"Laurence Payne" wrote in message
...
On Mon, 24 Aug 2009 15:59:17 +0100, "Keith G"
wrote:

Note the record deck sits (without suspension) in a massive plinth made
from
kitchen worktop offcuts and sits on a two inch thick 'grano' paving slab
(painted black) on firm, rubber 'doorstop' feet. The 'hifi stand' with the
extra weight in it (valve amp and large SS power amp) is pretty firmly
stuck
to the ground (concrete floor under weedy/cheapskate bedroom carpet) and I
can quite definitely say the sound from that deck has *by far* the best
bass
and pin sharp clarity I have ever heard from any turntable!

(That said, the other tt I use atm is a simple Technics deck with 'squidgy
suspension' built-in and I like that one just as much!)

So what characteristics does the Technics have to compensate for its
*by far* inferior bass and clarity?


Here's a little 'furry' pic of it (I'm into handheld/low-light MF atm):

http://www.moirac.adsl24.co.uk/showntell/Technics.JPG

Anyway, no idea - the AT moving coil cart probably helps...??



One deck is close to a speaker, another is actually on top of one! Of
course THOSE decks never feed THAT speaker?


Calm down, dear!

I have used decks parked on speakers before now but the deck in that pic was
just parked up. Trust me, I do like (very much) the sound I get from my
kit - or it'd be a damn sight different to wot it is, but I think you need
to free your mind off from a load of 'audiophile/anti-audiophile' prejudice
and misconceptions...



Are the speakers you actually listen to cramped against walls and
other equipment in that way? Do they sound different/better given a
bit more space to work in?


So many questions! I bet you drove your parents mad when you were a kid!

I've lost track, if the speakers you refer to are the ones with the IMF in,
they're history - the speakers I've got and use atm are crammed in but not
against the wall and sound absolutely fine to me; whether you or anyone else
would agree is another thing, but that's not really germane....

Tell me summat, have you ever been in a secondhand record shop and asked the
owner to 'put a record on' to try it? They invariably have utterly mediocre
kit - 'mid-fi' Technics decks and amps; speakers with no name on - and the
sound is usually quite *exquisite*!! Similarly, the more junk and clutter in
my room, the better the sound, I find!!

(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!! ;-)

On Mon, 24 Aug 2009 16:49:28 +0100, "David Looser"
wrote:


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.

Yup. And it probably got very loud with only a few watts input. If
we were prepared to let our speakers take up rather more space,
speaker design (and amp. power) could be very different :-)