Don't knock paper. It has practically ideal properties for a cone. I've spent much of my previous life trying to emulate it's properties with an engineered plastic for better consistency with some success.
My favourite material sounds very similar to yours. When you say 'high pressure compression molding' do you mean injection molding or a some sort of 2 part vacuum form? I would dearly love to know your patent no. but if it hasn't been granted, I understand if you don't reply.
My material is now sadly Unobtainium.
But what size cones were these prototypes? I'm still trying to get a handle on your mg moving mass variation. Was this weighing the cones directly rather than measuring T/S parameters?
Can't see a capacitive effect, myself. From my experience, I would still go back to the triboelectric mechanism if these plasticisers were changing in level; the world of static is a very messy, awkward one to deal with, no simple answers that I've seen ...
The use of cable supports, to me, is all about trying to control this to some degree ...
Frank
.. evidently more seriously than the Hirata, Quan or Listening Tests.
JC, did you actually test Blowtorch with Hirata? Did Quan say why Blowtorch will fail his test?
Modulating open Loop BW affects -
Can we modify a circuit to change its open-loop BW at a modulated rate of our choosing? Maybe injection of a squarewave or selection/changing of a strategic C in the circuit. Then as the OPA-BW is changing at various rates, measure the IM and PIM? Something for the SIM guys? [wrong forum?] Thx - RNMarsh
Can we modify a circuit to change its open-loop BW at a modulated rate of our choosing? Maybe injection of a squarewave or selection/changing of a strategic C in the circuit. Then as the OPA-BW is changing at various rates, measure the IM and PIM? Something for the SIM guys? [wrong forum?] Thx - RNMarsh
The thing is, whatever does happen must finally translate into an electrical behaviour in the circuits that are decoding and amplifying the audio signal. So, there are at least 2 ways of dealing with such things, which will typically mean a mixture of the two: either have the circuitry stay vulnerable to these effects, but eliminate the chance of the "bad" things getting through by removing the causes, or adding effective shielding; or, otherwise, make the circuit bulletproof, "radiation harden" it so to speak, by the design or topology, or the way it's assembled.
So, if you put together a really "tough" circuit, one that can shrug off spurious effects, then it will not show any problems or variations with the environment it's in -- what cables are used, the metals involved, etc ...
Frank
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Yes, that's exactly my way, fas42.
Pre-amps with oversized current ability, protected by low serial resistance (< 150 ohms), able to afford any charges, from shortcut to open loop, including any capacitances.
Power amps stable enough and protected, able to deal with no overshoot with X10 cables capacitances, flat impedance enclosures (cost some added calculations, inductances, resistances and capacitors).
Great care of hf (emi/rfi) problems, including ground loops care, focused on the feedback return points.
All that, very basic in the professional area, in fact, apart enclosure impedance flattering.
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That has not yet been determined, but I suspect Ron might be protecting John from having to explain the results.
Scott, since you are now an 'expert' on the causes of PIM distortion, could you please tell me how a CTC Blowtorch could generate any significant PIM? What would be the mechanism? I DO know of two PIM generating mechanisms so far:
One is generated from a nonlinear input stage with high dV/dT
The other is very high non-linear capacitance from a power fet, for example, associated with a relatively high impedance.
Know any others? How about the Blowtorch? Where is the PIM distortion mechanism?
One is generated from a nonlinear input stage with high dV/dT
The other is very high non-linear capacitance from a power fet, for example, associated with a relatively high impedance.
Know any others? How about the Blowtorch? Where is the PIM distortion mechanism?
Kgrlee,
Sorry it was bisphenol-A used in polycarbonate plastics but I was only using that as and example. Many flexible plastics that are not considered eleastomers do have some form of plasticizers added to them. As I said it was just a theory I had so no proof either way. Just looking for that missing link, like Big Foot.
I never said anything against paper just that it would be harder to control the actual final thickness than something else. I know that most of what we call paper is not exactly correct as there are many other additives including reticulated fibers and cotton fibers. If I hadn't developed my material I would have gone in that direction.And I was talking about compression molding, that is what I think that DuPont was attempting to do to consolidate the composite fibers after coating the fibers with polypro. My material is only unobtanium in that I am the only one who knows the formula for the material. The composites uses both Kevlar and Carbon fiber as the base fibers. It was much to easy to create an extremely rigid cone, I made some for development for a client and used only carbon fibers and it was for a subwoofer, I could literally stand on the apex of the cone, I weight about 180lbs and they would not collapse. Problem was that as you got that rigid the sound was horrible. A so called perfectly rigid cone may sound like what we want but my testing didn't exactly agree with that premise. This is what I hate about others attempts at a rigid composite cone made with rigid epoxy resins, they just sound nasty to me and measure that way also.
Sorry it was bisphenol-A used in polycarbonate plastics but I was only using that as and example. Many flexible plastics that are not considered eleastomers do have some form of plasticizers added to them. As I said it was just a theory I had so no proof either way. Just looking for that missing link, like Big Foot.
I never said anything against paper just that it would be harder to control the actual final thickness than something else. I know that most of what we call paper is not exactly correct as there are many other additives including reticulated fibers and cotton fibers. If I hadn't developed my material I would have gone in that direction.And I was talking about compression molding, that is what I think that DuPont was attempting to do to consolidate the composite fibers after coating the fibers with polypro. My material is only unobtanium in that I am the only one who knows the formula for the material. The composites uses both Kevlar and Carbon fiber as the base fibers. It was much to easy to create an extremely rigid cone, I made some for development for a client and used only carbon fibers and it was for a subwoofer, I could literally stand on the apex of the cone, I weight about 180lbs and they would not collapse. Problem was that as you got that rigid the sound was horrible. A so called perfectly rigid cone may sound like what we want but my testing didn't exactly agree with that premise. This is what I hate about others attempts at a rigid composite cone made with rigid epoxy resins, they just sound nasty to me and measure that way also.
DMT. I found the things crawling on the wall a little disconcerting, but then it was the classic case of being under observation by ostensible friends, and I really didn't feel comfortable with them.
BPA is a comonomer in the condensation polymerization- it is NOT an additive for polycarbonate.
A lot of effort is being made to try to explain effects for which there is no evidence. Unlike Scott, I haven't written opamp app notes or designed landmark audio circuits, but I have some small experience in the electrical and dielectric properties of plastics. Indeed, nearly everything in fashion audio I've seen dealing with dielectrics would have to be three steps better to even rise to the level of ca-ca.
Even when used only in the frequencies it did not fractionate ? And filtered with high slope ?
I had build a little enclosure with a focal loudspeaker (kevlar and resin), and the cone was sounding pretty good.
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Christophe,
I was going to add that caveat but thought not to go that far into it since this is so off topic here. Yes if you stay below the frequency that are smaller than the cone diameter you won't have a problem with cone break up but that is not the most common mode to use a driver. That is a different case and I agree that then I wouldn't see that kind of cone breakup.
I was going to add that caveat but thought not to go that far into it since this is so off topic here. Yes if you stay below the frequency that are smaller than the cone diameter you won't have a problem with cone break up but that is not the most common mode to use a driver. That is a different case and I agree that then I wouldn't see that kind of cone breakup.
To generate FM/PIM/whatever requires a voltage dependent reactance, no? A simple folded cascode, no inductors, very low impedance at the "mid points" between active devices, and transconductance output - where is the mechanism located? The first half drives a low Z and the second half is driven into a low Z. Gain of maybe 10. I don't get the argument.
Thanks,
Chris
Thanks,
Chris
Sy,
Sounds like I am talking to one of my chemist friends at Bayer. What type of work were you doing with plastics and dielectrics? As I was saying I was only suggesting some kind of answer to some of the things asked about cables and changes over time. That is why I twist the wire in opposite direction when I am sending speakers to the North or South Hemisphere. Just Kidding. I will stay out of the argument about cables, I have no side to take.
Sounds like I am talking to one of my chemist friends at Bayer. What type of work were you doing with plastics and dielectrics? As I was saying I was only suggesting some kind of answer to some of the things asked about cables and changes over time. That is why I twist the wire in opposite direction when I am sending speakers to the North or South Hemisphere. Just Kidding. I will stay out of the argument about cables, I have no side to take.
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