I personally think how fast it starts is pretty high on the list of priorities. The resoning behind this is:
Imagine a live concert scenario. What is the firt thing you hear - its the leading edge of the instrument (no room acoustics involved). Imagine what you would hear if you smudged this envelope?
What is the lat thing you hear - it's the room acoustics - reflected sound. Imagine what you would hear if you smudged this. It would be like using a more reflective room that echoes more.
So what sound is most unnatural, a slowly decaying sound or a slowly rising one?
Also how does waterfall indicate the rising envelope (impulse response)?
Actually step response (ability to approximate a square wave) is also important. It shows both frequency response and coherence.
Just some food for thought.
Imagine a live concert scenario. What is the firt thing you hear - its the leading edge of the instrument (no room acoustics involved). Imagine what you would hear if you smudged this envelope?
What is the lat thing you hear - it's the room acoustics - reflected sound. Imagine what you would hear if you smudged this. It would be like using a more reflective room that echoes more.
So what sound is most unnatural, a slowly decaying sound or a slowly rising one?
Also how does waterfall indicate the rising envelope (impulse response)?
Actually step response (ability to approximate a square wave) is also important. It shows both frequency response and coherence.
Just some food for thought.
Eh? 
No argument about optimal system damping characteristics being desirable, but MC drivers aren't bouncing around like space hoppers last I checked. 
Around F0 they resemble a 'mass on a spring' to some extent, but motion is limited by the electromechanical damping -which also incidentally dominates the entire rising response ('acceleration') BW up to the mass corner, from which point upward mass itself becomes the dominant factor. Below F0, you have your suspension / spring effects where mass is largely irrelevant. All of which is another way of saying that as far as oscillatory action is concerned, optimal system Q is nominally the 'transient perfect' 0.5 which only has the single let-go point and the fastest rise / settling time. Higher & you have excess ringing, lower and you're overdamped and not tracking accurately. This is aside from output created by controlled resonance or flex of the cone substrate of course, other than the fact that lower mass is likely to allow greater resonant sensitivity.
No argument about optimal system damping characteristics being desirable, but MC drivers aren't bouncing around like space hoppers last I checked. Around F0 they resemble a 'mass on a spring' to some extent, but motion is limited by the electromechanical damping -which also incidentally dominates the entire rising response ('acceleration') BW up to the mass corner, from which point upward mass itself becomes the dominant factor. Below F0, you have your suspension / spring effects where mass is largely irrelevant. All of which is another way of saying that as far as oscillatory action is concerned, optimal system Q is nominally the 'transient perfect' 0.5 which only has the single let-go point and the fastest rise / settling time. Higher & you have excess ringing, lower and you're overdamped and not tracking accurately. This is aside from output created by controlled resonance or flex of the cone substrate of course, other than the fact that lower mass is likely to allow greater resonant sensitivity.
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Poles appart....
Hi Scottmoose,
I am happy to say I totally disagree with everything you said here....!
I don't have the time at the mo and I am on my phone not lap top so don't have access to documents.....
Suffice to say you are totally wrong on all counts and I don't want to offer mere opinions....I will wait until I can access my documents and present some facts.
Cheers
Derek.
Eh?
Hi Scottmoose,
I am happy to say I totally disagree with everything you said here....!
I don't have the time at the mo and I am on my phone not lap top so don't have access to documents.....
Suffice to say you are totally wrong on all counts and I don't want to offer mere opinions....I will wait until I can access my documents and present some facts.
Cheers
Derek.
You are of course entitled to disagree; however, I seem to recall another thread where you raised exactly the same thing some time ago, in which Tom Danley, John Kreskovsky, David Smith & a number of others also expressed similar reservations.
Below Fh, in the rising response / acceleration BW, Q dominates. Above, mass dominates until VC inductance rolls it off, or you have a transition from oscillatory to resonant / bending behaviour to extend the useable upper frequency BW (until VC inductance finally takes over). Transient perfect (or as near as is possible) system Q within the rising response BW is 0.5 since it is accurately tracking the signal. These are all facts.
Below Fh, in the rising response / acceleration BW, Q dominates. Above, mass dominates until VC inductance rolls it off, or you have a transition from oscillatory to resonant / bending behaviour to extend the useable upper frequency BW (until VC inductance finally takes over). Transient perfect (or as near as is possible) system Q within the rising response BW is 0.5 since it is accurately tracking the signal. These are all facts.
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Hi Derek,
I will agree that rise time is usually not much of a measurable issue but is very noticeable acoustically. You will discover this if you own a keyboard with adjustable enveleope controls. Try playing a piano note with slowed attack - it's no longer a piano!. Try playing it with increased sustain - same piano just the pedal has been used!
Step response is actually not just one frequency. It is the most challenging test as a square wave contains an infinite number of increasing harmonics in theory. In terms of what the cone is doing - it's trying to respond to a sudden voltage change (not frequency amplitude change).
Then there is the other remaining issue with loudspeaker cones - imaging. Of course this is mainly a combination of other factors but also the cone and dispersion profile.
And people wonder if their cables are expensive enough!
I will agree that rise time is usually not much of a measurable issue but is very noticeable acoustically. You will discover this if you own a keyboard with adjustable enveleope controls. Try playing a piano note with slowed attack - it's no longer a piano!. Try playing it with increased sustain - same piano just the pedal has been used!
Step response is actually not just one frequency. It is the most challenging test as a square wave contains an infinite number of increasing harmonics in theory. In terms of what the cone is doing - it's trying to respond to a sudden voltage change (not frequency amplitude change).
Then there is the other remaining issue with loudspeaker cones - imaging. Of course this is mainly a combination of other factors but also the cone and dispersion profile.
And people wonder if their cables are expensive enough!
Taken from a magnetohydrodynamic drive no doubt?
I have one of those leading from the front gate to the garage.
There is a DIYaudio group buy for the Eikona 2.
Details here
http://www.diyaudio.com/forums/group-buys/264660-jordan-eikona-2-group-buy.html
Details here
http://www.diyaudio.com/forums/group-buys/264660-jordan-eikona-2-group-buy.html
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