MODULATED lobing and response

[phase_accurate]

But how do you make the leap between the two ?

Because ther is NO leap IMO !! The outcome of both will be the same !

Regards

Charles

[sreten]

I'm confusing myself here :

Consider the cases, two tones 100Hz and 1KHz, two drivers.
One driver gets 100Hz, driver A , the other 1Khz, driver B.
Both cases driver B is mounted to the moving parts of driver A.

Case 1

Driver A is large, driver B is small.
(Basically A produces 100Hz, B produces 1Khz)

The combination will produce an output with phase relationships
between the two signals that do not exist in the original signal,
i.e. the time axis for B is being modulated ?
i.e. the 1kHz tone is frequency modulated ?

If A and B are both fixed in position this does not occur.

Case 2

Driver A is small, driver B is large
(Basically A modulates B's position, B produces all the sound)

This is equivalent to a single driver ?

Phase relationships are maintained compared to the original signal.

This is where I get confused

sreten.

[sreten]

Originally posted by Svante


Agree. This would be the best.

So what about the ambulance, will there be a doppler shift in that case?

And for the extra-long-throw speaker?

The ambulance I believe is case 1 above,
its case 2 that causing me the trouble

sreten.

[Svante]

Originally posted by sreten
Case 2

Driver A is small, driver B is large
(Basically A modulates B's position, B produces all the sound)

This is equivalent to a single driver ?

Phase relationships are maintained compared to the original signal.

This is where I get confused

sreten.

Ahh, now I see. You think of the phase relationship between the drivers. The explanation, I think, lies in that the 100Hz tone is also slightly distorted by the doppler effect. There will be harmonics as a result of the motion. A 100 Hz tone that is frequency modulated with 100 Hz, is equivalent to a distorted 100Hz tone, right? These harmonics are probably far smaller than the usual forms of distortion in loudspeakers, but might be important for understanding the concept above.

I'll *have* to do the experiment some day!