On Fri, 09 Jan 2004 19:10:09 GMT, ow
(Goofball_star_dot_etal) wrote:

On Fri, 9 Jan 2004 18:12:59 +0000 (UTC), (Stewart
Pinkerton) wrote:

On Fri, 09 Jan 2004 16:20:14 GMT, henryf
wrote:

The point is: There exist examples of the power delivered by
things depending on what the surroundings do with their
output. (Contrast this with the original quote from Peter
Larsen above.)

No, there exist examples of local intensity levels varying with
surroundings, there are *no* examples of total radiated power
changing.
--

So if I pull the directors off a yagi I will see no increase in
reflected power as measured by my directional coupler?

Sure you will, but that's just a reflection (ahem!) of coupling
efficiency, and note that you will indeed have altered the directivity
of the array.
--

Stewart Pinkerton | Music is Art - Audio is Engineering

On Fri, 09 Jan 2004 19:10:09 GMT, ow
(Goofball_star_dot_etal) wrote:

On Fri, 9 Jan 2004 18:12:59 +0000 (UTC), (Stewart
Pinkerton) wrote:

On Fri, 09 Jan 2004 16:20:14 GMT, henryf
wrote:

The point is: There exist examples of the power delivered by
things depending on what the surroundings do with their
output. (Contrast this with the original quote from Peter
Larsen above.)

No, there exist examples of local intensity levels varying with
surroundings, there are *no* examples of total radiated power
changing.
--

So if I pull the directors off a yagi I will see no increase in
reflected power as measured by my directional coupler?

Sure you will, but that's just a reflection (ahem!) of coupling
efficiency, and note that you will indeed have altered the directivity
of the array.
--

Stewart Pinkerton | Music is Art - Audio is Engineering

On Fri, 09 Jan 2004 19:10:09 GMT, ow
(Goofball_star_dot_etal) wrote:

On Fri, 9 Jan 2004 18:12:59 +0000 (UTC), (Stewart
Pinkerton) wrote:

On Fri, 09 Jan 2004 16:20:14 GMT, henryf
wrote:

The point is: There exist examples of the power delivered by
things depending on what the surroundings do with their
output. (Contrast this with the original quote from Peter
Larsen above.)

No, there exist examples of local intensity levels varying with
surroundings, there are *no* examples of total radiated power
changing.
--

So if I pull the directors off a yagi I will see no increase in
reflected power as measured by my directional coupler?

Sure you will, but that's just a reflection (ahem!) of coupling
efficiency, and note that you will indeed have altered the directivity
of the array.
--

Stewart Pinkerton | Music is Art - Audio is Engineering

On Fri, 09 Jan 2004 19:10:09 GMT, ow
(Goofball_star_dot_etal) wrote:

On Fri, 9 Jan 2004 18:12:59 +0000 (UTC), (Stewart
Pinkerton) wrote:

On Fri, 09 Jan 2004 16:20:14 GMT, henryf
wrote:

The point is: There exist examples of the power delivered by
things depending on what the surroundings do with their
output. (Contrast this with the original quote from Peter
Larsen above.)

No, there exist examples of local intensity levels varying with
surroundings, there are *no* examples of total radiated power
changing.
--

So if I pull the directors off a yagi I will see no increase in
reflected power as measured by my directional coupler?

Sure you will, but that's just a reflection (ahem!) of coupling
efficiency, and note that you will indeed have altered the directivity
of the array.
--

Stewart Pinkerton | Music is Art - Audio is Engineering

On Sat, 10 Jan 2004 08:44:25 +0000 (UTC),
(Stewart Pinkerton) wrote:

On Fri, 09 Jan 2004 19:10:09 GMT, ow
(Goofball_star_dot_etal) wrote:

On Fri, 9 Jan 2004 18:12:59 +0000 (UTC), (Stewart
Pinkerton) wrote:

On Fri, 09 Jan 2004 16:20:14 GMT, henryf
wrote:

The point is: There exist examples of the power delivered by
things depending on what the surroundings do with their
output. (Contrast this with the original quote from Peter
Larsen above.)

No, there exist examples of local intensity levels varying with
surroundings, there are *no* examples of
changing.
--

So if I pull the directors off a yagi I will see no increase in
reflected power as measured by my directional coupler?

Sure you will, but that's just a reflection (ahem!) of coupling
efficiency, and note that you will indeed have altered the directivity
of the array.
--


So "total radiated power" is not foward power minus reflected power
(neglecting any small resistive losses in the antenna)?

This whole discussion has been about consevation of energy and
coupling efficiency. If you do indeed get four times the power density
over half a sphere surface compared to a whole sphere, conservation
of energy says you have to double the (acoustic) power input. This can
come from coupling efficiency changes or increased electrical input.
If the transducer is 100% efficient it *must* come from increased
electrical input but if it is only 1% efficient this is not a
requirement.

You all lose.

On Sat, 10 Jan 2004 08:44:25 +0000 (UTC),
(Stewart Pinkerton) wrote:

On Fri, 09 Jan 2004 19:10:09 GMT, ow
(Goofball_star_dot_etal) wrote:

On Fri, 9 Jan 2004 18:12:59 +0000 (UTC), (Stewart
Pinkerton) wrote:

On Fri, 09 Jan 2004 16:20:14 GMT, henryf
wrote:

The point is: There exist examples of the power delivered by
things depending on what the surroundings do with their
output. (Contrast this with the original quote from Peter
Larsen above.)

No, there exist examples of local intensity levels varying with
surroundings, there are *no* examples of
changing.
--

So if I pull the directors off a yagi I will see no increase in
reflected power as measured by my directional coupler?

Sure you will, but that's just a reflection (ahem!) of coupling
efficiency, and note that you will indeed have altered the directivity
of the array.
--


So "total radiated power" is not foward power minus reflected power
(neglecting any small resistive losses in the antenna)?

This whole discussion has been about consevation of energy and
coupling efficiency. If you do indeed get four times the power density
over half a sphere surface compared to a whole sphere, conservation
of energy says you have to double the (acoustic) power input. This can
come from coupling efficiency changes or increased electrical input.
If the transducer is 100% efficient it *must* come from increased
electrical input but if it is only 1% efficient this is not a
requirement.

You all lose.

On Sat, 10 Jan 2004 08:44:25 +0000 (UTC),
(Stewart Pinkerton) wrote:

On Fri, 09 Jan 2004 19:10:09 GMT, ow
(Goofball_star_dot_etal) wrote:

On Fri, 9 Jan 2004 18:12:59 +0000 (UTC), (Stewart
Pinkerton) wrote:

On Fri, 09 Jan 2004 16:20:14 GMT, henryf
wrote:

The point is: There exist examples of the power delivered by
things depending on what the surroundings do with their
output. (Contrast this with the original quote from Peter
Larsen above.)

No, there exist examples of local intensity levels varying with
surroundings, there are *no* examples of
changing.
--

So if I pull the directors off a yagi I will see no increase in
reflected power as measured by my directional coupler?

Sure you will, but that's just a reflection (ahem!) of coupling
efficiency, and note that you will indeed have altered the directivity
of the array.
--


So "total radiated power" is not foward power minus reflected power
(neglecting any small resistive losses in the antenna)?

This whole discussion has been about consevation of energy and
coupling efficiency. If you do indeed get four times the power density
over half a sphere surface compared to a whole sphere, conservation
of energy says you have to double the (acoustic) power input. This can
come from coupling efficiency changes or increased electrical input.
If the transducer is 100% efficient it *must* come from increased
electrical input but if it is only 1% efficient this is not a
requirement.

You all lose.

On Sat, 10 Jan 2004 08:44:25 +0000 (UTC),
(Stewart Pinkerton) wrote:

On Fri, 09 Jan 2004 19:10:09 GMT, ow
(Goofball_star_dot_etal) wrote:

On Fri, 9 Jan 2004 18:12:59 +0000 (UTC), (Stewart
Pinkerton) wrote:

On Fri, 09 Jan 2004 16:20:14 GMT, henryf
wrote:

The point is: There exist examples of the power delivered by
things depending on what the surroundings do with their
output. (Contrast this with the original quote from Peter
Larsen above.)

No, there exist examples of local intensity levels varying with
surroundings, there are *no* examples of
changing.
--

So if I pull the directors off a yagi I will see no increase in
reflected power as measured by my directional coupler?

Sure you will, but that's just a reflection (ahem!) of coupling
efficiency, and note that you will indeed have altered the directivity
of the array.
--


So "total radiated power" is not foward power minus reflected power
(neglecting any small resistive losses in the antenna)?

This whole discussion has been about consevation of energy and
coupling efficiency. If you do indeed get four times the power density
over half a sphere surface compared to a whole sphere, conservation
of energy says you have to double the (acoustic) power input. This can
come from coupling efficiency changes or increased electrical input.
If the transducer is 100% efficient it *must* come from increased
electrical input but if it is only 1% efficient this is not a
requirement.

You all lose.

On Tue, 06 Jan 2004 21:35:30 +0100, Peter Larsen
wrote:

Stewart Pinkerton wrote:

On Tue, 06 Jan 2004 13:18:10 +0100, Peter Larsen
wrote:

Metal is as poor as kevlar unless you are very good at making
cross-overs. If you are very good at making cross-overs then something
that is rigid in the pass band is attractive.

The B&W Kevlar drivers are not rigid in the pass band, they are
*designed* to move into bending mode.

Yes, yes, yes, kevlar units (x) tend to have a nice smooth drastically
rising response because of that well designed breakup, but eventually
things do get to steep dips, the major issue is of course the rising
response, they are possibly not heavy enough to remain linear when
breaking up ... it would be great if somebody could explain this better.

This is nonsense. *All* pistonic drivers have a 3dB/octave rising
response due to directivity changes as the radiated wavelength
approaches the diameter of the cone. This has *nothing* to do with
movement into bending mode, which in fact corrects this rise by
progressively reducing the radiating area with increasing frequency.
--

Stewart Pinkerton | Music is Art - Audio is Engineering

On Tue, 06 Jan 2004 21:35:30 +0100, Peter Larsen
wrote:

Stewart Pinkerton wrote:

On Tue, 06 Jan 2004 13:18:10 +0100, Peter Larsen
wrote:

Metal is as poor as kevlar unless you are very good at making
cross-overs. If you are very good at making cross-overs then something
that is rigid in the pass band is attractive.

The B&W Kevlar drivers are not rigid in the pass band, they are
*designed* to move into bending mode.

Yes, yes, yes, kevlar units (x) tend to have a nice smooth drastically
rising response because of that well designed breakup, but eventually
things do get to steep dips, the major issue is of course the rising
response, they are possibly not heavy enough to remain linear when
breaking up ... it would be great if somebody could explain this better.

This is nonsense. *All* pistonic drivers have a 3dB/octave rising
response due to directivity changes as the radiated wavelength
approaches the diameter of the cone. This has *nothing* to do with
movement into bending mode, which in fact corrects this rise by
progressively reducing the radiating area with increasing frequency.
--

Stewart Pinkerton | Music is Art - Audio is Engineering

On Tue, 06 Jan 2004 21:35:30 +0100, Peter Larsen
wrote:

Stewart Pinkerton wrote:

On Tue, 06 Jan 2004 13:18:10 +0100, Peter Larsen
wrote:

Metal is as poor as kevlar unless you are very good at making
cross-overs. If you are very good at making cross-overs then something
that is rigid in the pass band is attractive.

The B&W Kevlar drivers are not rigid in the pass band, they are
*designed* to move into bending mode.

Yes, yes, yes, kevlar units (x) tend to have a nice smooth drastically
rising response because of that well designed breakup, but eventually
things do get to steep dips, the major issue is of course the rising
response, they are possibly not heavy enough to remain linear when
breaking up ... it would be great if somebody could explain this better.

This is nonsense. *All* pistonic drivers have a 3dB/octave rising
response due to directivity changes as the radiated wavelength
approaches the diameter of the cone. This has *nothing* to do with
movement into bending mode, which in fact corrects this rise by
progressively reducing the radiating area with increasing frequency.
--

Stewart Pinkerton | Music is Art - Audio is Engineering

On Tue, 06 Jan 2004 21:35:30 +0100, Peter Larsen
wrote:

Stewart Pinkerton wrote:

On Tue, 06 Jan 2004 13:18:10 +0100, Peter Larsen
wrote:

Metal is as poor as kevlar unless you are very good at making
cross-overs. If you are very good at making cross-overs then something
that is rigid in the pass band is attractive.

The B&W Kevlar drivers are not rigid in the pass band, they are
*designed* to move into bending mode.

Yes, yes, yes, kevlar units (x) tend to have a nice smooth drastically
rising response because of that well designed breakup, but eventually
things do get to steep dips, the major issue is of course the rising
response, they are possibly not heavy enough to remain linear when
breaking up ... it would be great if somebody could explain this better.

This is nonsense. *All* pistonic drivers have a 3dB/octave rising
response due to directivity changes as the radiated wavelength
approaches the diameter of the cone. This has *nothing* to do with
movement into bending mode, which in fact corrects this rise by
progressively reducing the radiating area with increasing frequency.
--

Stewart Pinkerton | Music is Art - Audio is Engineering