I suspect using the charcoal filter mask in the backyard would end up with homeland security visiting...on the upside, I could make the breathing sounds and tell them "I find your lack of faith disturbing"..
jn
I think the way a harmonica player bends a note flat is by using the mouth cavity to place a strong filter on the vibrating tine, forcing its Fs lower.
If we do this with a speaker / cabinet combination, where the speaker Fs is forced lower by the cabinet resonance, does it sound as good as the case where the speaker Fs was lower initially - and the cabinet tuned to it?
If we do this with a speaker / cabinet combination, where the speaker Fs is forced lower by the cabinet resonance, does it sound as good as the case where the speaker Fs was lower initially - and the cabinet tuned to it?
I must honestly confess that I lost my appetite a bit after the past 10 pages or so.
But a promise is a promise and I will come back with a recorded sound spectrum with a varying HF bias.
The impedance peak at HF is no longer an issue after being measured so well by Demian.
Still interesting to know what causes this HF peak, but the ESL will have to be taken apart for that, and that’s not something I want to do with such a delicate instrument.
Hans
I had to back burner that last november due to a family death. Life always seems to get in the way.
I have acquired a few tiny gauge enameled wires to see if they can fit the vc interstitials. I really hope I do not have to use the #49 awg, I can't even see that wire.
I also popped the front plate and cut it in half to eliminate shorted turn eddies.
Haven't tried to unglue the spider yet, not sure how to do it without destroying the spider, chemistry and horribly caustic chemicals may be in my future..
At the moment, working on a toroidal coil winder, almost finished with it.
If anybody is interested in the build details, I could cobble up some pics and start a thread in the parts or equipment forum..
jn
Jn,
Maybe someone here could pick up the winding job for you?
I think everyone’s interested to see the results of this.
(Sorry - can’t volunteer since I’m a bit of a klutz when it comes to practical things like this requiring patience and hand-eye coordination).
The frequency shift stuff never bothered me, as you said I already knew the answer
.So where are the waveform envelope plots with their own frequency content which may or may not be audible?
BTW the brickwall filter I used on the cymbal files was neither FIR or IIR but an FFT filter the length of the entire file so there are no skirts, ripples, or phase shift. This is not practical for more that a 20 or 30sec clip but eliminates a lot of issues.
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The frequency shift stuff never bothered me, as you said I already knew the answer
So where are the waveform envelope plots with their own frequency content which may or may not be audible?
I put it here:
https://www.diyaudio.com/forums/the-lounge/349926-black-hole-3.html#post6090981
Nobody seemed to have an interest.
jn
Resonances, nasty things not conducive to "accuracy"
You have to consider the speaker/enclosure as a complete system. The Q of the system will determine how "good" it sounds. All the multitude of different cabinet designs are basically about extending/controlling the response of the low frequency driver, so choose your poison, some of them are quite extreme, like using different gases inside the cabinet for example
Ed, one of my techs, while cleaning up a 32 year old Vendetta phono preamp during a repair, pulled out some 1,1,1 Trichloro... from my supply cabinet. That is the stuff HE prefers! I haven't used the stuff in years. At the same time, they closed a school here in Berkeley because they found traces of 1,1,1 ... in the soil deeply below the school. Too much worry? IBM used to have small swimming pool size vats of the stuff, open to the world, at their plant in San Jose in the 1960's. Saw it myself.
xtly! That is why slowing down C by using a heavy gas is a bad idea, since it makes the enclosure look larger for standing waves
Moot.
It is the same, in the end, of making the box physiclly larger. If the woofer box needs to be of suffiicent size to support standing waves at frequencies generated it does not matter how you get there, you will see the same standing waves.
dave
Now that you mention it, yah. Lots of pinch points, and I suspect the wire size means lots of torque driving the rings. That's the kind of machine I could see an engineer try to use with a necktie.
Glad you mentioned it, I really should put a chain guard on the toroid rotation stuff. I'n using a NEMA 17 motor with 76 oz-in, no idea how aggressively it would try to squish a finger.
jn
And if you don't understand what the tool is showing you start seeing "current distortion" on the output terminals of your amplifier
I see the 5kHz example confused me at first. I'm still looking for a complex signal that has envelope issues in a known audible critical band when Brickwalled at 22.05kHz.
EDIT - Your PM box is full did you get my second message today?
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Decades ago it was what I and others used to develop photo-sensitive printed circuit cards. Used to breath a lot of it. (Perhaps that explains a lot...)
You can do your MEK bit this October 31st with out any worries!
Of course since Home Depot sells it over the counter in their paint department, how hazardous could it be!!! (Was very surprised to see it there!)
Sorry, the 5khz was provided only to show that the FFT is spread and fuzzy. The intent was to show that as the exponential progresses, the actual exponential spectral lines will sweep inwards to zero.
The second, my plot, overlays the sincos modulation with an exponential that duplicates the sincos modulation rate of change.
The effect will be sidebands that initially are wide enough that the USB will be removed, but as the exponential progresses, the sidebands pull in.
By using the gibbs artifact as a detector, you could easily shift Fs to see where the filter stops removing content.
Given that this waveform starts hard and immediately modulates down, looking for the gibbs would be compromised. That is why I was talking about time mirroring this waveform so the onset of gibbs is clear.
I did not get the second one, but just deleted some stuff from the inbox.
jn
Its a Hazardous substance because it is flammable. But, Several cancer investigations have proved negative. So far then, it seems safe as a non-cancer causing chemical.
-RNM
