The overal area above and below zero must be equal over infinit time, and also dependent on driver characteristics. How this area distribution occurs depends on driver performance. Therefore, it is not necessary to have a large negative impulse immediately following the first positive one. Also bear in mind that if you use a Klippel system to do DC measurement, lots of drivers have DC. How fast the impulse goes to zero also depends on low frequency content decay.gedlee said:
Jmmlc said:
Mmmh, sounds like lack of arguments here... What I did or do on other locations is irrelevant in this place.
I think you overestimate a lot what you "invented" a bunch of years ago (what's new since 15 years ?) and most of your affirmations have no evidences (they can be true, nevertheless).
For your information, I don't care about you as a person (I don't know you personally) , only the methods and (lack of) argumentations you use on all the forum, mainly affirmations defined as evidences and systematic discredit of the "concurrence" (as you did with Earl). So, please, don't whine as a poor victim, it's a weak argumentum ad misericordiam. I've never named you as a "enemy of science", but that you use bad science when it suits you : hasty generalization !
I assume totally what I wrote on my blog since it's only facts that everybody can verify. You're welcome to make a right to reply and, of course, I'll make apologizes if I did something wrong.
But, let's go back to the topic : it's funny that you don't write the same way here about Earl works. Where are the criticisms ? What are your thoughts, conclusions and evidences ?
Are you afraid of what !?
Jipi.
gedlee said:
Read the first sentence of the post Earl.
We also don't like topics being brought here from other sites. As mentioned, if you have a problem, take it somewhere else. This is not a site for the spiteful nor whiners or ingrates. Stay on topic and remain polite regardless of the strength of your argument.
Thank you.
If you have further comments on this, feel free to email me.
When there is a DC component in the response, as measurable, and due to asymmetry of motor, suspension, etc. The transfer of energy into acoustic energy cannot be symmetric can it. Thus how can impulse response be totally symmetric?gedlee said:
Additionally, not data has been published under real measurement conditions, that impulse will be totally symmetric. It only exists under ideal conditions.
This is all incorrect.
There is never a DC component to the pressure response except under very idealistic conditions - an air tight room would exhibit a static pressure rise from a DC cone displacement, although such a pressure change would be miniscule and would disipate to zero unless the cabinet itself were air-tight. And, I know of no space for acoustic measurements that is air-tight - you would suffocate. Hence, no "real world" impulse response can have anything but an average level of zero.
There is never a DC component to the pressure response except under very idealistic conditions - an air tight room would exhibit a static pressure rise from a DC cone displacement, although such a pressure change would be miniscule and would disipate to zero unless the cabinet itself were air-tight. And, I know of no space for acoustic measurements that is air-tight - you would suffocate. Hence, no "real world" impulse response can have anything but an average level of zero.
Let me ask one fundamental question. If damping in a motor is not symmetric, how can it produce equal acoustic energy in both directions?gedlee said:
Additionally if the whole driver is in the room there can be not rise in static pressure. This is mainly because there is not change in total volume when the driver has DC cone displacement. You know better than that. If you are talking about an air tight speaker enclosure, then it's a different story. Don't mix things up now. We are all getting old...
This is a tweeter with response of 30KHz. This kind of impulse basically has the kind of first and inverted relationship. The real difference between the second impulse in the 2nd impulse of the 4 comparision is that the peak of the inverted impulse in this one is not larger than the first part. Thus better.
Attachments
No. Because if you actually do the calculation of the condition you described, it would be very dependent on driver performance. I have not seen any driver that would measure perfectly symmetric on a Klippel system. So the response cannot be symmetric. This is very different from idealistic math models.gedlee said:
Attachments
soongsc said:
I don't see how Bl symmetry has anything to do with it. The issue is the actual acoustic response to an impulse. The driver is at rest, there is an impulse with some overshoot and damping, then the driver is at rest again. The total response in integration about the rest position must be zero when integrated to infinity. Integrate over a finite time period, sure, it won't be zero, but that's not what matters.
Dave
