There have been some posts lately stating that drivers with less cone movement usually sound better. There have also been some posts lately discussing the doppler effect and cone movement. I was pondering these ideas the other day and I came to realize that there are things I just don't understand about cone movement.
First I have some basic assumptions. Maybe somebody can tell me if these are correct.
1) I assume that cone movement should be linear with respect to the input signal.
2) To change the volume(SPL output), the length of linear excursion is changed. More excursion equals greater SPL, but doesn't really effect the frequencies being produced. I am aware that the ends of the spectrum tend to rolloff with higher SPLs though.
From this I can conclude that doppler effect should not be a problem. High frequencies naturally ride along the edge of a low frequency signal. If the cone is tracing the signal linearly, then it doesn't matter how far the cone moves, it will produce the correct frequencies.
I can imagine though that it is harder to stop a cone precisely at the correct point when that cone is moving a long distance. On the other hand, since everything is linear the cone stopping points(think digital input signal) are further apart and there is more room for error.
Now on to long throw drivers.
Long throw drivers are employed to get more bass out of a smaller driver.
However, this seems to contradict my assumption above that changing excursion does not affect frequency.
Does the shape of the cone effect the frequencies that it can produce. Like does increasing the concaveness of the cone provide lower frequencies, but with a loss of efficiency. This makes sense to me. However, if the cone must move a long way to get sufficient SPL out of the low frequencies and it must move linearly with input signal, then it seems to me that the higher frequencies are going to be too loud. I think this only because some cones can move very little to produce higher frequencies. Unless the concave shape also effects the efficiency of the high frequencies.
One often hears long throw drivers touted for bass because they are lighter and easier to control. On the other hand they must move a lot further which would seem to effect the ability to stop the cone accurately enough to play higher frequencies well.
Perhaps it is all about cone shape. I have noticed that cones typically have a rising response pattern. This lends support to the idea moving the cone linearly, but far enough to get adequate bass is too far for the high frequencies, thus the cone shape is wrong to produce a flat response.
Do flatter cones have a flatter frequency response?
If anyone can make sense of this rambling and provide some insight I would appreciate it.
