John,
Easythink just doesn't hack it 🙁.
One problem for sure is that we cannot easily pick up chaotic behaviour because it tends to dress up as noise in the usual measurements.
Easythink just doesn't hack it 🙁.
One problem for sure is that we cannot easily pick up chaotic behaviour because it tends to dress up as noise in the usual measurements.
Thanks scott.
Two things of note.
1. He's modelled both L and R as having frequency dependence in the case of a lossy inductor. He also gave spice models which have controlled sources embedded.
2. He does NOT consider the motion of the coil in the gap and the change of inductance as a consequence, the term I call I dL/dt. He used a generic lossy model using a power series.
His students use single tone testing to measure L/R. Note I mentioned a two tone test, I'm less concerned with sine response, more to complex signals.
jn
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The real problem is how far away from the attractor is the system getting. The assumption has to be that the system is bounded of course, and movement around the attractor is noise or distortion. So, when is spice gonna put up chaotic elements?
Me, I'll worry about what we can do.
ps..your sentence:
""For that reason, chaotic behaviour may be expected, and an accurate model should display the same.""
The statement that an entity may be expected is not the same as it is there. Since we can measure the pressure wave of the driver, it should be simple enough for you to show us that chaos needs to be invoked.
jn
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Lets see..I look it up, this is what I get:
""it used shooting methods as its base algorithm; and it pioneered the use of Krylov subspace methods.""
So, lets see. Are we talking about hitting clay pigeons with a 12 gauge, spray painting them as they fly, or throwing them faster than light at warp 5?
It looks like the methodology they use is quite consistent with what we are discussing...where'd you get that stuff??? I've never heard of it...😱
jn
Read further...
"Effectively they build a periodically time-varying linear model of the circuit. This is significant as periodically time-varying linear models, unlike the time-invariant linear models used by the traditional small-signal analyses (AC and noise) exhibit frequency conversion."
i.e. I would think better (or at least some) answers for your multi-tone excitations.
Umm, scott...that's why I said ""It looks like the methodology they use is quite consistent with what we are discussing""
Guess my lack of humor got in the way, eh?
jn
It was VOLVO that awoke the industry and taught how to do passenger passive/active safety right. The news today is the smart MEMS sensors (call me BOSCH).
KBK what do you imply with this buttkicker?
To use it as a motional body-sensory exciter for to increase the ‘feeling’ of bass in lieu of adequate LF acoustic output from speakers?
From M.Leach paper (thanks Scott):
Jn, do you agree with the underlined part?
George
edit: this underlined part:
""The back emf is given by BluD, where B is the magnetic flux in the air gap, l is the effective length of wire that cuts the flux, and uD is the mechanical velocity of the diaphragm. The back emf due to the diaphragm motion exhibits a band-pass effect that decreases toward zero as frequency is increased above the fundamental resonance
frequency of the driver. At the higher frequencies, the impedance is dominated by the inductance. ""
All that is said is that the inductance is in series with the generator. Makes a low pass.
The real question is, is the inductance constant, or does a copper ring reduce the inductance volume due to lenz effect? And, is the inductance volume for a specific frequency constant if the coil is moving in the gap as a result of large scale low frequency drive?
jn
Well, LTspice does have random functions, should be quite straightforward to introduce 'chaotic' behaviours ...
Thanks (*)
No
Yes, without or.
Again no, it’s not. But there are some implications when viewing coil as a copper ring.
There is the static copper ring, a foil acting as a shorted turn, installed in some drivers for inductance reduction.
The coil can not function exactly as a shorted ring:
-Even if it’s ends are shorted by the amplifier’s very low output impedance, there are some electric circuit elements between the coil in the gap and the amp output impedance. This “short” is lossy and frequency dependent.
-It is moving.
-Signal current flows through it.
Have I misunderstood you?
George
(*) Edit: But uD increases with frequency. How the effect ‘decreases toward zero’ past the fc ? And what about the band pass?
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Jacco,
Thanks for the spelling correction. Scheel were always the top line seats that I have ever seen.
John,
Would the lenz affect be proportional to the induced field created by the voicecoil? And wouldn't you still have this effect without a Faraday ring without a shorted winding from the copper tube?
Thanks for the spelling correction. Scheel were always the top line seats that I have ever seen.
John,
Would the lenz affect be proportional to the induced field created by the voicecoil? And wouldn't you still have this effect without a Faraday ring without a shorted winding from the copper tube?
I'd love to be a fly on the wall for that conversation.
Probably none of the above. How about a control test - A true coaxial 12 AWG cable with the same insulator materials tested exactly the same way shows no significant difference free air vs. across the same wood and metal bench. Similarly, running a common 50 ohm coax that was sitting around in the lab shows no difference on the bench vs. off.
It has to be external to the UUT and measurement equipment - or that other person is truly in the room and messing with us, we just can't see them.
Sorry to poop the party. So what was all that conversation about terminating speaker cables at something close to nominal cable impedance after the tweeter's control of speaker impedance peters out...
Dave
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