It seems so but I do not know the mechanism behind it.
In this paper
http://www.klippel.de/fileadmin/klippel/Files/Know_How/Literature/Papers/Aging%20of%20loudspeaker%20suspension_Klippel.pdf
the condition of recoverable spider creep is addressed, as well as the permanent reduction of spider stiffness with accumulated mechanical work (both resulting in lowering of Fr)
On another paper though
http://www.klippel.de/fileadmin/klippel/Files/Know_How/Literature/Papers/Diagnosis_and_remedy_of_Nonlinearities_00.pdf
Fr raises with increasing displacement on all the woofers tested but each with a different rate. I don’t know the way these tests were conducted, for how long the test tones were applied (look at ‘Resonance frequency versus displacement’ diagrams, page 24 and on)
Thank you Tom for the valuable input.
Follows a quote from the link below:
Group Delay
Now, since GD is the mathematical expression of the phase abruptness at each frequency, can one make a linear freq sweep, get the phase curve, export it to excel, select a frequency interval and for each delta frequency get the -delta phase and so calculate the GD in each frequency interval and plot the GD vs frequency?
Good news. Someone has already done the hard work
http://www.cjs-labs.com/sitebuildercontent/sitebuilderfiles/GroupDelay.pdf
Eq. 3 is for phase data from linear and logarithmic sweeps.
The simpler Eq. 4 is for data from linear sweep.
George
>Edit
John
For the inductance change, klipper paper above, has such diagrams.
As for the ‘velocity based eddy losses’, do you mean eddy current losses in the magnetic circuit or eddies in the air due to cone movement? (I have no idea for any of these two)
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Many speakers are designed for a more flat power response.... believing that we wont be listening in near field and esp not at 1 meter. But when someone does listen to it close in, it will be too bright. IMO, I look for flat freq response at 1m and flat power response, far field. Both. Not so easy to do. But it will sound best/balanced at any listening distance.
What are some of the ways this is done?
THx-RNMarsh
What are some of the ways this is done?
THx-RNMarsh
If you look to the response curves of my horn, you will see two response curves. One is the traditional 1 meter distance, the other was form the listening point.
You can nearly supperpose them.
How is this possible ? Horn.
Thank you, gentlemen, for the input on driver suspensions - I would very much agree that more work in this area would be worthy. What is interesting, for me, is that the improved behaviour from conditioning lasts during a listening session, but is then lost after a few hours of non-activity - the whole conditioning ritual then has to be repeated.
In subjective terms, the benefit is that the low level information is resolved far more clearly - in mechanical terms this would translate to the cone being able to accelerate and decelerate in far finer and more precise gradations - correctly "follows the waveform", IOW.
In subjective terms, the benefit is that the low level information is resolved far more clearly - in mechanical terms this would translate to the cone being able to accelerate and decelerate in far finer and more precise gradations - correctly "follows the waveform", IOW.
To me, this is an absolutely crucial test of the complete system - it must be able to reproduce very high level, high frequency information 100% cleanly, in terms of how it registers at the ear. If it can't do this, then the sound will always be compromised, always. Why live, unamplified sound has that powerful intensity up close as a signature, is because the high frequencies are not degraded - and the human hearing system has no problems processing it. But present that intensity with added distortion, via a compromised reproduction system - and it's a nightmare! Impossible to live with, tolerate for any period of time - the "magic" of a correctly working system is because those high frequencies are making sense.
Directivity (an attribute of horns) or your listening very close or your walls are very very absorptive, either will allow that observation
John,
I wish I knew where the test results were from actually doing acoustical tests on the inverted dome Focal tweeter with a Ti dome but don't know where they are right now. I will tell you that though it looks like that tweeter is producing those high frequencies up high I will tell you that it is not correlated with the signal, it is mostly resonant energy, that is why they bother so many people. I don't think there is any way you can electrically correct this and unless you are going to dope that Ti dome with something I higly doubt that Wilson has changed anything on that device. There are to many people who have tried to make those tweeters work, they are a very poor design and an inverted dome is a bad idea simply as you have created a resonant cavity right in front of that dome. They keep changing the dome material but the basic design just doesn't work well. I still have parts for those drivers laying around, I have tested more than one of those models and they all have the same inherent problems. If you look at the force application to the back of the dome the way they do it, it make very little sense. I'll call it a modern version of a Whizzer cone!
I wish I knew where the test results were from actually doing acoustical tests on the inverted dome Focal tweeter with a Ti dome but don't know where they are right now. I will tell you that though it looks like that tweeter is producing those high frequencies up high I will tell you that it is not correlated with the signal, it is mostly resonant energy, that is why they bother so many people. I don't think there is any way you can electrically correct this and unless you are going to dope that Ti dome with something I higly doubt that Wilson has changed anything on that device. There are to many people who have tried to make those tweeters work, they are a very poor design and an inverted dome is a bad idea simply as you have created a resonant cavity right in front of that dome. They keep changing the dome material but the basic design just doesn't work well. I still have parts for those drivers laying around, I have tested more than one of those models and they all have the same inherent problems. If you look at the force application to the back of the dome the way they do it, it make very little sense. I'll call it a modern version of a Whizzer cone!
Well, the way I would test it, for myself, is to deliberately go up close to a purely acoustic musical instrument that produces a spectrum very strong in high frequencies, as part of its intrinsic tonality. If that irritated me intensely, I couldn't take it, then it would be fair enough to always deliberately moderate those frequencies in a playback system - there is something in my hearing makeup that is not coping.
For me, there is no such problem - hence, I want the audio setup to replicate that sound spectrum.
He has the plan in PDF - http://gr-research.com/pdf/X-LS Encore box.pdf .
It is a dead copy of my Colombian boxes. (I looked inside).
Half sheet (or a little more) 3/4" masonite and someone with a good table saw /
router.
Full sheet <40$ and no more than 100$ labor - plans are simple.
OS
FAS42,
I don't care what they say in their marketing and so called technical papers, Focal does many things strictly for marketing purposes. I have test some of their cone drivers also and am not impressed with their designs. They are very expensive middle of the road devices. They do make a nice looking finished package though in their enclosures.
I don't care what they say in their marketing and so called technical papers, Focal does many things strictly for marketing purposes. I have test some of their cone drivers also and am not impressed with their designs. They are very expensive middle of the road devices. They do make a nice looking finished package though in their enclosures.
Curiosity drove me to have a quick look around, and found this: http://resolution.nodecube.net/products/pdfs/Monitoring/Focal%20CMS65.pdf.
I'm not seeing anything particularly offensive in the treble area - care to point out what's faulty here?
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