Peter Larsen wrote:
Richard Crowley wrote:

C-W were also showing a 12-inch(?) driver which they would
plug directly into the 120V power mains outlet in the hotel room.

Julian Hirsch tested it for stereo review, "the only result was a very loud
noise, no harm to the speaker"

Was any of that noise actually at 60 Hz, though, or was it all 120, 180, etc.?

There were rumors that C-W cracked some plaster and had to
pay the hotel for repairs. And other rumors that the JBL demos
in another room down the hall, were reproducing such realistic
gunshot sounds (thanks to their 075 ring radiator tweeters, aka.
the "acoustic laser") that the LAPD was called out to investigate.

I recall an incident with a falling chandelier in the Ritz-Carlton some time
around then....
--scott

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

In article , "David Looser" wrote:
"Richard Crowley" wrote in message
...
"David Looser" wrote ...
"Scott Dorsey" wrote...
When stereo came in, corner horns went away.

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

If you had ever seen one, you would know better.


Did you bother to read the thread before posting that response? I thought
not.

I did see the corner speaker *I'm* talking about, which is more than you
have. And it was a bass-reflex.


OK, near the end of Speaker Builder magazine, and in Audio Express, a fellow was putting ports
or "bass reflex" into his horns to get improved performance.

So it might be either or both.

greg

Scott Dorsey wrote:

Peter Larsen wrote:
Richard Crowley wrote:

C-W were also showing a 12-inch(?) driver which they would
plug directly into the 120V power mains outlet in the hotel room.

Julian Hirsch tested it for stereo review, "the only result was a
very loud noise, no harm to the speaker"

Was any of that noise actually at 60 Hz, though, or was it all 120,
180, etc.?

This is something I read in a borrowed magazine in 1978-ish - do not expect
too much detail, what he tested was whether the subwoofer in question would
survive being connected to a 115 volt outlet as claimed and so it did.

Kind regards

Peter Larsen

Peter Larsen wrote:
Richard Crowley wrote:

C-W were also showing a 12-inch(?) driver which they would
plug directly into the 120V power mains outlet in the hotel room.

Julian Hirsch tested it for stereo review, "the only result was a very loud
noise, no harm to the speaker"

I heard that Bose fitted a light bulb in series with the drivers
(inside the cabinet) to protect them, and to allow the 'mains demo'.
Don't know how true it is though.

--
Eiron.

"Richard Crowley" wrote in message


C-W were also showing a 12-inch(?) driver which they would
plug directly into the 120V power mains outlet in the
hotel room.

There were rumors that C-W cracked some plaster and had to
pay the hotel for repairs.

I believe that there are a number of extant modern woofers that can survive
this treatment for at least a little while without tricks. 120 volts is the
same as 1,800 watts into 8 ohms, which is not an unbelievable amount of
power by modern standards.

On the tricks side, a woofer with a 60.0 Hz resonance would not absorb
*that* much power, given that its impedance at 60 Hz might be as high as 30
ohms or more, and only 4 amps (480 watts) or less would need to be
dissipated in the voice coil.

Also, a woofer with a 16 ohm voice could would need to absorb *only* 900
watts. A mere pittance! ;-)

"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.

On Mon, 24 Aug 2009 15:58:04 -0400, "Arny Krueger"
wrote:

"Richard Crowley" wrote in message


C-W were also showing a 12-inch(?) driver which they would
plug directly into the 120V power mains outlet in the
hotel room.

There were rumors that C-W cracked some plaster and had to
pay the hotel for repairs.

I believe that there are a number of extant modern woofers that can survive
this treatment for at least a little while without tricks. 120 volts is the
same as 1,800 watts into 8 ohms, which is not an unbelievable amount of
power by modern standards.

On the tricks side, a woofer with a 60.0 Hz resonance would not absorb
*that* much power, given that its impedance at 60 Hz might be as high as 30
ohms or more, and only 4 amps (480 watts) or less would need to be
dissipated in the voice coil.

Also, a woofer with a 16 ohm voice could would need to absorb *only* 900
watts. A mere pittance! ;-)


Mmmm.... Don't try it over here in England.

d

David Looser wrote:
"Richard Crowley" wrote ...
"David Looser" wrote ...
"Scott Dorsey" wrote...
When stereo came in, corner horns went away.

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

If you had ever seen one, you would know better.


Did you bother to read the thread before posting that response? I
thought not.

I did read the thread. It appears to be talking about the classic
Klipsch corner. You can go back and review it if you're confused.

I did see the corner speaker *I'm* talking about, which is more than
you have. And it was a bass-reflex.

I guess we don't know which corner speaker *you're* talking about,
then.

"Laurence Payne" wrote in message
...
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 :-)


Still is for a lot of people who prefer low power amp+efficient speakers to
*powerhouse* arcwelder+ironing board setups....

"Dave Plowman (News)" wrote in message
...
In article ,
Keith G wrote:
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,

Probably the same family as the BC1 - from an original BBC design study.

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....

I suppose you tried inverting the driver?


Sure - first port of call after turning the whole box upside down; then I
tried all sorts of fiddling about before I spoke to DK Loudspeakers:

http://www.moirac.adsl24.co.uk/showntell/DSCN1476.JPG