This looks interesting...
https://audioxpress.com/index.php/n...ne-x-portable-speaker-with-built-in-subwoofer
Quote: "This new driver utilizes a combination of moving and stationary magnets to create a force that is equal and opposite to the force caused by large air pressure changes within a speaker enclosure. "
If I understand it correctly, the driver's motor is designed essentially to negate the impact of the "air spring" of the sealed enclosure that it's mounted in, so the only restoring force for the cone is the spider and surround. And if that's correct, this is a driver that probably won't work properly UNLESS it's mounted in a correctly-sized sealed enclosure.
https://audioxpress.com/index.php/n...ne-x-portable-speaker-with-built-in-subwoofer
Quote: "This new driver utilizes a combination of moving and stationary magnets to create a force that is equal and opposite to the force caused by large air pressure changes within a speaker enclosure. "
If I understand it correctly, the driver's motor is designed essentially to negate the impact of the "air spring" of the sealed enclosure that it's mounted in, so the only restoring force for the cone is the spider and surround. And if that's correct, this is a driver that probably won't work properly UNLESS it's mounted in a correctly-sized sealed enclosure.
Some more information here - https://www.msn.com/en-us/lifestyle...aker-knocked-us-for-a-loop-at-ces/ar-AA169pSJ
Looks like they've got permanent magnets strapped to the voice coil When the coil moves, the magnets move as well.
Looks like they've got permanent magnets strapped to the voice coil When the coil moves, the magnets move as well.
Yikes, what a word salad of technobabble. Whatever writer they hired to come up with that marketing chit didn't understand what the engineer was telling them. Anyone know what their patent number is assuming it's actually something new and not just marketing BS applied to a conventional Rice-Kellogg motor or moving magnet type driver?
Edit: Found the patent for the other driver in the speaker, but nothing for the woofer.
Edit: Found the patent for the other driver in the speaker, but nothing for the woofer.
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Ah, you're right. Just now see in the specs that the midrange and tweeter are more conventional drivers. Less novel a design than I was giving it credit for. Guess we'll see if they've a pending patent that'll eventually come out about this. Novel motor topologies fascinate me as much as intentionally obfuscating marketing speak infuriates me.
I haven't read it, but this application may be what you're looking for. It references other applications as well.
https://patents.google.com/patent/EP4094451A1/
https://patents.google.com/patent/EP4094451A1/
Ah, thank you. That is much more enlightening than their site. If that's what they use then it actually isn't new. Mayht actually had something similar last year that Sonos bought the rights to. Brane should be alright legally, though, since magnetic negative spring drivers have been patented here and there since at least the '60s. (More on that here.) So, yeah, hardly a new idea, though being able to come out with a workable product with it is rarer. Be interesting to see how it measures up if anyone gets their hands on one.
Mayht have similar technologies: https://audioxpress.com/article/patent-review-linear-motor-magnet-assembly-and-loudspeaker-unit
I tried to work my way through the VC description, but got hopefully lost in words. The device is an opposing membrane push-pull device -not unlike conventional push-pull coumpound?- where a magnetic field provides a negative spring? Could someone here explain in comprehensible terms how the negative spring working is achieved?
What we suspect is similar to the Mayht driver, which the background to is discussed in this article: https://piratelogic.nl/data/docs/voicecoil/VC-August-2022.pdf#page=16
This is a good visualization from that article of what's probably happening in this new driver (not that you can tell from the technobabble gibberish in their marketing chit):
The motor at the bottom is conventional and you can ignore that, but pay attention to the magnets tucked up under the triple joint. That's what's most likely happening here. If you visualize the cone going in and out, you can see how it would invert the compliance curve under excursion. It could either be balanced to be perfectly flat within its linear range, but wanting to go very unstable outside of it. I suspect they're trying to stay right on that balance point, but it'd be really tricky to get just right. There's good reason why these have stayed in the patents and prototypes and not been a product brought to market. It'll be interesting to see if they manage to pull it off and what the distortion looks like after it.
Let us say the cone moves outward. There and then the in-box air exercises a sucking force, tending to oppose outward movement, which then has to be counteracted. The second motor is supposed to counteract that. But that is the part I cannot get my head around.
But, after all, ideally, we still are dealing with a driver under free air instead of in-box conditions. In terms of cone excursion the same amount of air still has to be moved to create bass.
But, after all, ideally, we still are dealing with a driver under free air instead of in-box conditions. In terms of cone excursion the same amount of air still has to be moved to create bass.
Thus why they're shoving as big a driver into the box as they can fix, 8", iirc. The funky magnet arrangement is just there to counter the compliance of the driver's suspension and the air spring of the box so it'll behave free air...except it has a box to trap the backwave. So, their goal seems to be making an infinite baffle for an 8" driver in an enclosure with the volume of a small shoebox.
My concerns arise from the inherent instability of it. Distortion could well be very high (which, subjectively, would give the perception of fuller, richer bass for a portable speaker) and the secondary magnet setup could easily tip over its balance point and throw the cone to the limits of its suspension or such it into the motor. No system is perfectly sealed and the voice coil isn't going to always be energized to hold things in place, so I'm curious as to how they plan to avoid that second issue.
My concerns arise from the inherent instability of it. Distortion could well be very high (which, subjectively, would give the perception of fuller, richer bass for a portable speaker) and the secondary magnet setup could easily tip over its balance point and throw the cone to the limits of its suspension or such it into the motor. No system is perfectly sealed and the voice coil isn't going to always be energized to hold things in place, so I'm curious as to how they plan to avoid that second issue.
If the second motor is underhung, it should quickly looses force once the voice coil is outside of the gap? Thus reverting the device back into a 'normal' driver outside a predetermined range, where the overhung motor still exerts control. Things should be scaled differently then the patent shows, a good patent doesn't show everything just enough to have 'broad' coverage.
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