We are about to send a paper cone for tooling - looks really promising in simulations. If reality is complying with simulations then it looks like a retro style low Mms but 10mm Xlbl low distortion beast with high sensitivity (say 5dB more). the flip side is that the box will need to be bigger and some bass extension is lost in passive designs
Awesome! I'm going with a Seas L26RO4Y and acceleration feedback for now, but that sounds like a killer upgrade when it is finally out.
this has probably been asked if so point me to the post - Lars what are your thoughts on traditional dust cap vs inverted dust cap? from a simpletons POV here it looks like it doesn't seem to make a difference one way or the other, but I notice you have traditional button dust caps on the alu's and inverted on the papers.
Love to hear Lars’ answer too, but I wonder if he as time to do any real work with us all posting our requests here.
eg. I’d like a beryllium cone 4” midrange with neo motor and Purifi suspection with300_z300Hz to 400-). 5mm x-‘ax and and
In my experience the convex or concave dust cap affects the geometry of the cone; and as we know geometry affects affects frequency response, both on and off axis.
Within one single cone + dust cap material, I’ve observed that inverted dust cap seems to improve dispersion, but this continuous curvature of the cone/dust cap may affect resonances. If you want to push out the resonances to a higher frequency, or dampen the resonances, you may need to adjust your geometryso adjusting the cone and/or dust cap profile can adjust that.
eg. I’d like a beryllium cone 4” midrange with neo motor and Purifi suspection with300_z300Hz to 400-). 5mm x-‘ax and and
In my experience the convex or concave dust cap affects the geometry of the cone; and as we know geometry affects affects frequency response, both on and off axis.
Within one single cone + dust cap material, I’ve observed that inverted dust cap seems to improve dispersion, but this continuous curvature of the cone/dust cap may affect resonances. If you want to push out the resonances to a higher frequency, or dampen the resonances, you may need to adjust your geometryso adjusting the cone and/or dust cap profile can adjust that.
normal vs inverted dustcap: good question. inverted causes a bit more beaming (bowl shape works as a horn/waveguide) and a bump on the FR whilst sometimes allowing more BW (if the cone is deep enough). however, inverted challenges the clearance to the inner copper ring on top of the pole piece. We have tooled an inverted dustcap for rhe 6.5 Alu and the difference is not big (FR and dispersion)
The PTT8.0 preview driver looks absolutely brilliant!
Hi Lars, the PTT8.0's current distortion is extraordinary low. Is it because it's a 2 layer voice coil or larger motor/VC diameter? I think a 50mm or 2 layer VC driver for 6.5 inch would be very interesting!
Best,
Hi Lars, the PTT8.0's current distortion is extraordinary low. Is it because it's a 2 layer voice coil or larger motor/VC diameter? I think a 50mm or 2 layer VC driver for 6.5 inch would be very interesting!
Best,
Yes but then the sensitivity will be even lower.
Everyone was already complaining about the low sensitivity of the very first PTT6.5... trade-offs, trade-offs...
Everyone was already complaining about the low sensitivity of the very first PTT6.5... trade-offs, trade-offs...
Actually a lower sensitivity version of ptt6.5 models quite well in big bass reflex design with excellent bass extension. Like 30L tuned at 24hz. Makes good use of its long throw capability, easy to fit a port.
thank you 🙏
I am not sure if it’s the two layers or increased diameter or both that results in the lowered current distortion.
The 52mm coil requires a bigger dustcap to allow space for the ventilation holes that need to be bigger (more air to pass to to the large pole area). This challenges the 6.5 cone design. Would eat some bandwidth. not a problem for sub use of course
sensitivity could actually be higher since the 2 layer 52mm motor is lighter (lower coil mass) and about the same Bl compared to the 39mm 4L
Cool. Is frequency response also flat on back side? Is 30/60 degree response around 2 kHz improvable compared to aluminium cone? Are there plans with Textreme materials?
sorry, have not looked at backside response. The big motor will act as a lens. front side dispersion might be a tiny bit better than for the alu version.
TexTreme is clearly interesting but also challenging due to its anisotropic stiffness. We have some cone samples made long time ago and hopefully the project gets finished some time. We have lots of interesting stuff in the pipeline but too little time and hands
Anisotropic is the property of obtaining different values when observing or measuring something from different directions.
Had to google that one. Interesting. Could one maybe maybe make the cone curve asymmetrical to counter? I suppose its a nightmare to simulate, let alone trial and error.
Had to google that one. Interesting. Could one maybe maybe make the cone curve asymmetrical to counter? I suppose its a nightmare to simulate, let alone trial and error.
it can be simulated but requires 3D FEA models which are very slow and RAM consuming. Moreover, it s difficult to characterise the material when anisotropic. We prefer to let the computer do 1000's of trial and error runs aka shape optimisation. But did not say impossible of course.
its generally vers tough to do good drivers. Coax even more. Lets do a tweeter first. Coax has some hard to solve IMD issues
Deploying L26RO4Y as subwoofer or part of 3 way? Im looking into the latter my self
Anyone ever tried applying a bit of moongel or SkyGel to alu cones? The stuff is used to dampen cymbals, it is tacky and fairly light… so that got me thinking
textreme, tweeters, stop teasing us!
bliesma have set the bar pretty high for tweeters, but as we've seen with woofers, if anyone's gonna raise the tweeter bar its gonna be purifi.