This tells you, to some extent, that the top end of the woofer is really flopping around. And that there's a lot of detail information being lost in that speaker, via out of phase and inharmonic grunge.(<- Woofer complex distortions as a black box, requires careful unpacking)
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Depending on what part of the distortion of a driver is being dealt with, active suppression or control can only do so much. In the final analysis, it tends to be good at the super low frequencies - and that's just about it.
The rest is best tackled elsewhere. I was making cheap $7 - 7" woofers have what would appear to be the same waterfall plot as a $200 dynaudio 7", back in the early 90's. (I was an early buyer and user of 'liberty audio suite', and went total 24/7 OCD on mid woofers for about 2-3 years or more, close to 7 days a week.)
JN
I was wondering... the magnetic motor can be made better perhaps but it really is the suspension parts that tug a Lot on the cone beginning at very low displacements of the cone.
So..... can we make a coil/magnet assembly which can help to keep the cone moving in a greater linear distance .... against such tugging on the cone movement.
Maybe a voice coil that does Not have linear windings on it. More densely packed at ends and less dense at center, for example. Or a harder way might be a magnet surrounding the VC which has varying distance from different lengths of the VC.
THx-RNMarsh
I was wondering... the magnetic motor can be made better perhaps but it really is the suspension parts that tug a Lot on the cone beginning at very low displacements of the cone.
So..... can we make a coil/magnet assembly which can help to keep the cone moving in a greater linear distance .... against such tugging on the cone movement.
Maybe a voice coil that does Not have linear windings on it. More densely packed at ends and less dense at center, for example. Or a harder way might be a magnet surrounding the VC which has varying distance from different lengths of the VC.
THx-RNMarsh
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Both ideas are good. A variable density coil wind would work if layer one is inside the former, layer two outside.. Tight wind of a two layer provides the second layer a cylindrical surface, variable would not.
Your second option is one of pole profiling. I am used to using a variable profile to make the field more uniform, but sure, it is very conceivable that the faceplate and/or center pole piece could be profiled such that at long excursion, a uniformly wound vc would see more field. It would be interesting as well, as I believe the spider and surround would have to break in to achieve design nominal..
If that were so much an issue, you could also do a two layer tight pack, and a secondary variable pitch geometry that could be put in series with the main, or pulled out as a second coil used for adjustable suspension correction .
Too bad Richard, that was probably patentable.......you have now climbed into the same boat as me..
jn
Or design a more linear suspension? Rubber coated fiber (a typical spider) is not a particularly linear medium. And it can make noises as the fibers rub against each other. (Not especially class A per JC's mention above) More: Damper / Spider / Suspension | Best Command Some early speakers used flat metal springs for this which could be more linear but may impart a rotary action as they flex.
Acoustic suspension was supposed to replace the mechanical aspects with the trapped air mass behind the driver. Looks good on paper.
Acoustic suspension was supposed to replace the mechanical aspects with the trapped air mass behind the driver. Looks good on paper.
That's not a magnet! This is a magnet. Cern are shaking the tin for a much larger collider. Apparantly this is a prototype 16T magnet. I have no idea what 16 Tesla can do but I don't want to be close to it when running!
Apparantly the Crabbities are working well. Love this quote
I think I read that as they had an 8 Tonne trolley with liquid helium sloshing around inside. Rather them than me!
Apparantly the Crabbities are working well. Love this quote
I think I read that as they had an 8 Tonne trolley with liquid helium sloshing around inside. Rather them than me!
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There is a patent and product that uses segmented voice coils so that only the coil in the gap gets energy. It does improve the efficiency but at a major price for complexity. There are also efforts at shaped gaps etc. This is not really undiscovered territory. The limitation is manufacturing technology. However new materials and computerised coil winding machines open up new possibilities. E.G. microspeakers with squared off voicecoils. Tooling and setup is in the millions but very high return since every cell phone has at least 1.
Both ideas are good.
Too bad Richard, that was probably patentable.......you have now climbed into the same boat as me..
jn
Yeah, I know. But, creative problem solvers have no end to generating patentable ideas. Some work, such as, R&D, requires it.
The suspension alone can be made to move further in linear way. But seems to be limited by several factors in practice. So an off-setting magnetic field at the VC can keep that linearity going further for any given suspension.
Which way is easiest.... VC mod or magnet structure changed to extend the linear range of movement for the driver?
some sketches, please.
Make the non-patentability even greater. after all, why should only one person or driver company benefit. lets make it common-practice in the future of dynamic driver mfr-ing.
Then a way for DIY to do a proof of concept model.
THx-RNMarsh
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Like distortion? Read near the end of this Quad Reference ESL-2805 loudspeaker Measurements | Stereophile.com Also a reference for microphone distortion
Non-linear distortion is one of the lowest possible, until you remain in linear excursion area. Especially for differential drivers.
maroon is voice coil former
orange is voice coil wire.
Grey is iron.
But in looking at it, the vc should be underhung, so when it move towards the non cutaway section, the flux total goes up.
jn
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I'm not sure if superfluid sloshes.. but the stored energy in the field is huge..our super dipoles are only 3.5 tesla and store 1.45 megajoules..CERN goes big...
100 microns is fairly sloppy for things like that. We just tested a control system on a device that retains 50 nanometer accuracy during the move, settles to within 10 nm at the endpoints. Bigger hardware than that puny prototype dipole...
jn
pssst...my magnet's bigger than your magnet....
As said before, above the bass region fairly large electrostatic speakers have remarkable low harmonic distortion.
Audiostatics (ES600 and ES900) were measured well below 0.1% (over most parts of the audio bandwidth) and i´ve measured -iirc - Quads (29xx) ~0.01% (83 dB Spl/1m/1 kHz).
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Yes, that is my vision put to paper. Maybe with a dual VC... One could remove the center part of the top winding and leave only the ends and place ends in series with the first VC so as to pick up greater field at the ends only.
Got a drawing for that also?
THx-RNMarsh
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