Testing that speakers in phase?
 

don pearce wrote:

Eeyore wrote:
David Looser wrote:
"Don Pearce" wrote
"David Looser"
wrote:
"Don Pearce" wrote in message
Fan-based subwoofers will do it.

What's a "fan-based" subwoofer?, and what will they "do"?

David.

A rotating fan with variable pitch blades whose angle is modulated by
the bass signal. What they will do is reproduce 0.1Hz quite nicely.

Is this something you've just invented? because it seems utterly pointless
to me. And I don't know what you mean by "reproduce". 0.1Hz isn't "sound" by
any stretch of the imagination, it cannot be heard, and is actually too low
a frequency even to be readily sensed as movement. The only sort of device I
can imagine that will "reproduce" 0.1Hz, in the sense of doing something
that a human could detect (other than by sight), would be a moving platform.

All the DACs I know have inbuilt high pass filters anyway so I'd like to know
how you'd find 0.1 Hz coming out of an audio system.


Filters are finite things, there'll be some, you can be sure. And even
if you don't have a DAC that goes low enough, just pop on an audio sig gen.

What is it you have with grasping at straws ?

Graham

Testing that speakers in phase?
 

In article ,
tony sayer wrote:
You might be able to within a computer, but I was thinking about a chain
used to produce CDs, etc.


Its maintained and needed in broadcast exciters in order to maintain
those expensively produced processed waveforms;!...

Nothing in the broadcast chain I deal with - microphone through to
Digibeta TX tape - has that sort of LF response. Perish the thought. ;-)

--
*Why is it considered necessary to screw down the lid of a coffin?

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

Testing that speakers in phase?
 

Eeyore wrote:

don pearce wrote:

Eeyore wrote:
David Looser wrote:
"Don Pearce" wrote
"David Looser"
wrote:
"Don Pearce" wrote in message
Fan-based subwoofers will do it.

What's a "fan-based" subwoofer?, and what will they "do"?

David.

A rotating fan with variable pitch blades whose angle is modulated by
the bass signal. What they will do is reproduce 0.1Hz quite nicely.

Is this something you've just invented? because it seems utterly pointless
to me. And I don't know what you mean by "reproduce". 0.1Hz isn't "sound" by
any stretch of the imagination, it cannot be heard, and is actually too low
a frequency even to be readily sensed as movement. The only sort of device I
can imagine that will "reproduce" 0.1Hz, in the sense of doing something
that a human could detect (other than by sight), would be a moving platform.
All the DACs I know have inbuilt high pass filters anyway so I'd like to know
how you'd find 0.1 Hz coming out of an audio system.

Filters are finite things, there'll be some, you can be sure. And even
if you don't have a DAC that goes low enough, just pop on an audio sig gen.

What is it you have with grasping at straws ?

Graham


We're talking about the art of the possible, and I've just shown
everyone that there are people out there who are extending subwoofer
technology way down in frequency to areas where, even if the ears aren't
reacting. the rest of the body certainly is. Now maybe current CDs and
even DACs aren't responding well down there - why would they, there has
been nothing to reproduce and nothing to play it on. And as far as CDs
are concerned, that will probably remain so. But don't assume it will
stay that way for all media, particularly in the film industry where
they grab every new available sensation and pound it to death.

So no, I don't grasp at straws - I'm just not somebody who lives by the
motto "Nothing shall ever be done for the first time".

d

Testing that speakers in phase?
 

"don pearce" wrote in message
news:lsidnd6a0pTporzVnZ2dneKdnZydnZ2d@plusnet...


We're talking about the art of the possible, and I've just shown everyone
that there are people out there who are extending subwoofer technology way
down in frequency to areas where, even if the ears aren't reacting. the
rest of the body certainly is.

In the sub 1Hz region the body *can* respond, but it would take far more
power than the fan woofer could produce to do it.

Now maybe current CDs and even DACs aren't responding well down there -
why would they, there has been nothing to reproduce and nothing to play it
on. And as far as CDs are concerned, that will probably remain so. But
don't assume it will stay that way for all media, particularly in the film
industry where they grab every new available sensation and pound it to
death.

There was "Sensuround" some years ago, which used powerful sub-woofers to
produce a lot of low-frequency energy, but we were still talking about
frequencies above 5Hz. The fad died very quickly as the audiences were not
greatly impressed (many actively hated it), and there were serious problems
with sound leakage from cinemas, even structural damage. In the domestic
environment the problems would be even more severe. If you want sub 1Hz
"effects" then the only practical method is to move the body of the listener
with some sort of powered seat.


David.

Testing that speakers in phase?
 

On Wed, 7 May 2008 09:22:55 +0100, "David Looser"
wrote:

"don pearce" wrote in message
news:lsidnd6a0pTporzVnZ2dneKdnZydnZ2d@plusnet.. .


We're talking about the art of the possible, and I've just shown everyone
that there are people out there who are extending subwoofer technology way
down in frequency to areas where, even if the ears aren't reacting. the
rest of the body certainly is.

In the sub 1Hz region the body *can* respond, but it would take far more
power than the fan woofer could produce to do it.

Maybe - I don't know, having never tried it. ANyway this thing is
aimed more at the region from a few Hz to 30Hz, supplementing a normal
subwoofer. It may find applications, it may not. The big problem for
it at the moment is that there appears to be only the one manufacturer
and it costs a fortune. If things remain that way it will certainly
fail.

Now maybe current CDs and even DACs aren't responding well down there -
why would they, there has been nothing to reproduce and nothing to play it
on. And as far as CDs are concerned, that will probably remain so. But
don't assume it will stay that way for all media, particularly in the film
industry where they grab every new available sensation and pound it to
death.

There was "Sensuround" some years ago, which used powerful sub-woofers to
produce a lot of low-frequency energy, but we were still talking about
frequencies above 5Hz. The fad died very quickly as the audiences were not
greatly impressed (many actively hated it), and there were serious problems
with sound leakage from cinemas, even structural damage. In the domestic
environment the problems would be even more severe. If you want sub 1Hz
"effects" then the only practical method is to move the body of the listener
with some sort of powered seat.

I remember sensurround, and it wasn't good. Hard to say though whether
the problem was the thing itself or what they were doing with it. Even
with normal subwoofers cinema is still in the throes of putting
irritating rumbling and banging effects all over everything, whether
it needs it or not. Some foley artists need their legs slapped.

As for the powered seat thing, maybe, but I think the effect is pretty
much different to that of low frequency airborne pulsing. I've been in
the vicinity of a volcano when it was getting enthusiastic and the
feeling in the air was incredible - like having your head squeezed.
That was presumably the result of all the intense infrasonics in the
area.

d

--
Pearce Consulting
http://www.pearce.uk.com

Testing that speakers in phase?
 

In article ,
Don Pearce wrote:
I remember sensurround, and it wasn't good. Hard to say though whether
the problem was the thing itself or what they were doing with it. Even
with normal subwoofers cinema is still in the throes of putting
irritating rumbling and banging effects all over everything, whether
it needs it or not. Some foley artists need their legs slapped.

Heh heh. Foley artists would be very unlikely to have anything to do with
such FX. And in any case do what's required of them rather than being in
charge.

I do tend to get a bit p***ed off when the wrong person gets criticised
for this sort of thing. Saw a letter sent to a cameraman on 'The Bill'
complaining about wibbly-wobbly shots when he was only doing as he was
instructed to - and, I might add, against his better judgement.

--
*Beauty is in the eye of the beer holder *

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

Testing that speakers in phase?
 

On Wed, 07 May 2008 10:49:26 +0100, "Dave Plowman (News)"
wrote:

In article ,
Don Pearce wrote:
I remember sensurround, and it wasn't good. Hard to say though whether
the problem was the thing itself or what they were doing with it. Even
with normal subwoofers cinema is still in the throes of putting
irritating rumbling and banging effects all over everything, whether
it needs it or not. Some foley artists need their legs slapped.

Heh heh. Foley artists would be very unlikely to have anything to do with
such FX. And in any case do what's required of them rather than being in
charge.


What is and isn't Foley is a bit moot. But there is plenty going on in
films that is very definitely Foley and has me gnawing the furniture
in frustration. As for the "I was only obeying orders" defence. I
didn't buy it for the Krauts in WWII, and I don't buy it for the Foley
last night who made the breaking of the plastic lens of a car's rear
light sound like a plate glass window being hit with a sledgehammer.

I do tend to get a bit p***ed off when the wrong person gets criticised
for this sort of thing. Saw a letter sent to a cameraman on 'The Bill'
complaining about wibbly-wobbly shots when he was only doing as he was
instructed to - and, I might add, against his better judgement.

Then it's time some cameramen started telling directors not to be such
a pratt. Chances are they have vastly more experience in the job
anyway. David Lean did his own lighting and called his own shots.

d
--
Pearce Consulting
http://www.pearce.uk.com

Testing that speakers in phase?
 

In article ,
Don Pearce wrote:
I do tend to get a bit p***ed off when the wrong person gets criticised
for this sort of thing. Saw a letter sent to a cameraman on 'The Bill'
complaining about wibbly-wobbly shots when he was only doing as he was
instructed to - and, I might add, against his better judgement.

Then it's time some cameramen started telling directors not to be such
a pratt.

You're not a freelance, then?

Chances are they have vastly more experience in the job anyway. David
Lean did his own lighting and called his own shots.

They may or may not be. 'The Bill' has a vast spread of directors from
pretty green to very experienced. And although there will be co-operation
between them in how it is shot at the end of the day it's the director and
producer who have the final say, style wise. If the cameraman doesn't
accept this and do what he's told he will be sacked - I've seen it happen.

--
*Middle age is when work is a lot less fun - and fun a lot more work.

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

Testing that speakers in phase?
 

"Eeyore" wrote in
message
David Looser wrote:

"GSV Three Minds in a Can" wrote

Sure it can. You just need something around 0.1hz.

You won't get 0.1Hz through an audio amplifier!

You won't get 0.1Hz through a speaker either !

Sure you will - you will only notice the cone motion because the SPL will be
so low! ;-)

Testing that speakers in phase?
 

"David Looser" wrote in message
...
"don pearce" wrote in message
news:lsidnd6a0pTporzVnZ2dneKdnZydnZ2d@plusnet...


We're talking about the art of the possible, and I've just shown everyone
that there are people out there who are extending subwoofer technology
way down in frequency to areas where, even if the ears aren't reacting.
the rest of the body certainly is.

In the sub 1Hz region the body *can* respond, but it would take far more
power than the fan woofer could produce to do it.

There was an odd incident in my local boozer in Gloucester Place, W.1.,
probably about 20 years ago. One lunchtime there was suddenly something
between a noise and a feeling - my guess would be around 1 c.p.s, maybe
less, and it was extremely upsetting - to some people. About a tenth of the
customers said "what the f**** that?) and headed for the doors - me in the
lead - whereas the rest didn't seem to notice. The feelings I experienced
were great but indefinable discomfort and actual nausea.

I know a couple of the regulars were sound engineers - stadium rock
concerts, that sort of stuff - I deeply suspect them of playing silly
buggers although I never did find out for sure. The Guv'nor of the pub, who
was always up for a laugh, was one of those who didn't hear/feel it, and
clearly wasn't in on the joke.

Would anybody from this NG like to come clean after all these years...?

Geoff MacK