My point is not how the results are displayed...Its the results!
Thanks again for your reply and I agree with you:
"...that CSD does not show anything that the impulse response does not."
But, as I mentioned in my previous posts, that is not my point!
Re compression drivers and their matching (manditory) horns / waveguides.... They are not a solution for real world (mass market) home entertainment / music / movies / game etc...
Their size, expense, floor space requirements all add up to a WAF factor of zero... Only well heeled, single, 50 plus geeks (& DIY!) apply...
If one can accept the WAF compromises and cost, looked at in isolation many good compression drivers do show clean ( sub 1 milli second) CSD plots over the 500Hz / 1KHz up to their top end limits bandwidth.
Sub 1 milli second.... Mmmn, still 3 or 4 orders of magnitude to slow!
In addition the CD / horn combination must be crossed over (just like the ATC dome mid-range) at around 500 Hz to 1 Khz to a conventional space heater, er sorry bass mid driver with all its failings as described above.
One often overlooked point on conventional bass mid drivers, they typically burn off 90% to 99% of the amplifier power which feeds them as heat...!
This assumes typical Pro driver / box loading system efficiency of 98dB sensitivity (optimistic) and typical "audiophile" driver sensitivity of around 88dB sensitivity.
PS
The solution is never going to be a "mass on a spring" ( cone / dome / suspension) energised by a "space heater" (electro-magnetic motor...)
Electrostatics hint at whats possible... As do plasma tweeters, although size cost, WAF etc kick in big time...
Thin film technology holds some promise as does carbon nano tech and next gen printing.... I am betting around 2025 we will see exciting solutions hitting the mass market.
Thanks again for your reply and I agree with you:
"...that CSD does not show anything that the impulse response does not."
But, as I mentioned in my previous posts, that is not my point!
Re compression drivers and their matching (manditory) horns / waveguides.... They are not a solution for real world (mass market) home entertainment / music / movies / game etc...
Their size, expense, floor space requirements all add up to a WAF factor of zero... Only well heeled, single, 50 plus geeks (& DIY!) apply...
If one can accept the WAF compromises and cost, looked at in isolation many good compression drivers do show clean ( sub 1 milli second) CSD plots over the 500Hz / 1KHz up to their top end limits bandwidth.
Sub 1 milli second.... Mmmn, still 3 or 4 orders of magnitude to slow!
In addition the CD / horn combination must be crossed over (just like the ATC dome mid-range) at around 500 Hz to 1 Khz to a conventional space heater, er sorry bass mid driver with all its failings as described above.
One often overlooked point on conventional bass mid drivers, they typically burn off 90% to 99% of the amplifier power which feeds them as heat...!
This assumes typical Pro driver / box loading system efficiency of 98dB sensitivity (optimistic) and typical "audiophile" driver sensitivity of around 88dB sensitivity.
PS
The solution is never going to be a "mass on a spring" ( cone / dome / suspension) energised by a "space heater" (electro-magnetic motor...)
Electrostatics hint at whats possible... As do plasma tweeters, although size cost, WAF etc kick in big time...
Thin film technology holds some promise as does carbon nano tech and next gen printing.... I am betting around 2025 we will see exciting solutions hitting the mass market.
I'm trying to understand if this whole thing about "quick" and "detailed" sound from a driver is a bunch of nonsense. Based on what's been said here by Dr. Geddes and others, the only parameter that matters with respect to quickness is frequency response.
Basically it seems like two completely different drivers made of different materials have to have the same decay and impulse response if they have the same frequency response. One driver can't physically be any quicker or more detailed than another if its vibrating at the same frequency. Or maybe it can?
Some drivers, horns in particular, do seem more vivid and lifelike. Maybe its all in the lack of early reflections.
Last edited:
A good response alone isn't enough and this is the next issue (but it has been called as beyond the scope of this thread).
I would think the material makes a difference, but perhaps its either correctly producing the sound (flat FR) or not.
So your saying its not the driver itself?
In reality, you are never going to get to have two driver exactly the same due to manufacturing tolerances.
seems to me that even if two drivers have the same freq response the properties of materials play a part. Even if they have a flat response how can a high loss cone sound the same as a metal cone once they start to enter the region where the cone is flexing ? I realize this is probably overly simplistic but each material has a "sound"of its own and even if we tailor all the cones construction till we get a flat response, once the thing starts flexing it seem to me that the materials "sound" will start creeping in.
We seem to be caught in a bit of a loopIf the responses are the same they will sound the same but they're not so they won't, this is the problem when we think and talk in absolutes.
Let's say you have a ribbon compared to a large dome and both are playing in the 4-8 khz. Both are basically flat FR in this region and lowish nonlinear distortion. Neither is in break up.
So you have two very different drivers and masses but it seems as though they would sound the same (excluding dispersion) because they are both in sync with the same signal. OR can one be more "detailed" and "quicker" than the other?
As far as break up, I think this is in fact when (for a variety of reasons) the driver can't keep up with and be in sync with the signal, so its a failure of sorts.
Last edited:
Well yea, if the drivers are flat in the same 4-8 khz then they must have the same impulse and csd in the same region. So afaik they'd sound the same unless there are some other measurement I am missing, like acceleration maybe.
Let's not mix up discussions about measurements and perception, they are far from the same thing. In measurements, if the two devices have the same frequency response they they will have the same impulse response and CSD, but they don't have to sound the same - they can have different directivities. How these directivities interface with the room and enclosure matters a lot. We started talking about distortion in drivers, now it has spread to how loudspeakers sound in rooms - that's a huge jump. I suggest we stick to the drivers only and how they are measured and how the distortion is perceived.
This is the typical impossible discussion where you start by declaring that "drivers are imperfect", but then when someone shows you how to perfect them, you claim "They are not a solution for real world." Well they are, I have them, lots of people have them, but if they are impractical for you then its the limitations of your situation that are the problem not the technology.
it's hard to have a meaningful discussion about distortion in loudspeakers when as Scottjoplin pointed out, "when we think and talk in absolutes." we use words like linear and flat to talk about frequency response but what is the accepted definition flat or linear?
i long for the days when loudspeaker spec's where more like amplifier spec's ( I.E. 45HZ to 16KHZ +/- 3.5 db )
we know from Floyd Toole's work that there's a marked preference for flat response and Dr Geddes work says that linear response over a defined area (directivity) is even better.
but i'm still wondering if there's a way to work toward establishing a better understanding or defining a point where the majority of the subtle perceptible and measurable differences truly vanish.
i long for the days when loudspeaker spec's where more like amplifier spec's ( I.E. 45HZ to 16KHZ +/- 3.5 db )
we know from Floyd Toole's work that there's a marked preference for flat response and Dr Geddes work says that linear response over a defined area (directivity) is even better.
but i'm still wondering if there's a way to work toward establishing a better understanding or defining a point where the majority of the subtle perceptible and measurable differences truly vanish.
I believe that we are there, but most audiophools don't. That's because they don't want to give up their "god given right" to like what they want to like despite what the measurement (reality) says. To do this they must throw out the measurements as a hindrance to their freedom of choice. Under the objectives claims, the subjectivists become obsolete. A situation that they simply cannot abide by - they completely loose their power.
So there is no known scientific explanation for why horns sound more "vivid", except perhaps that how we perceive it because of directivity and less diffraction perhaps.