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Gotcha. Thanks for straightening me out. I'll look forward to the tweeter! Few

Thanks for your interest! I’m trying to get myself up to speed on SVD, and I’ve read that PCA is an application of SVD, but won’t pretend to know more than I do. The somewhat odd feature of empirical mode decomposition is that it doesn’t begin with an assumed set of basis functions (like the...

While trying to teach myself a bit about wavelet analysis as an alternative to Fourier transforms when measuring loudspeaker performance, I came across "empirical mode decomposition" (EMD) and the Hilbert-Huang transform. I've done a bit of searching and trying to extract the key ideas, but it...

The title is "Peter Lyngdorf and Purifi Audio Announce New Radiant Acoustics Speaker Brand." Since Lyngdorf is a cofounder of Purifi, and Lars Risbo is the chief technology officer at Purifi, and they're the primary designers for the Radiant speaker, it sounds to me like the Purifi crew has...

Here is one reference to the new speaker; I’ve seen others as well. Even The Audiophiliac has a review: https://www.youtube.com/channel/UC9wBmplRUhaCi-aNrkfgeTg Few

The Purifi calculations show ring radiators having less uniform directivity, with deep nulls off axis. The rings don't become effectively smaller at high frequency, although it would be grand if they did. And if aluminum “wants to move pistonically,” wouldn’t that move the break-up frequency...

Late to the party, but I wanted to thank Killingbeans for the Purifi link. That was the most useful thing I’ve read in a long time. Few

How about a stroboscope to view the diaphragm’s mode of motion? I just noticed Parts Express sells one with a flash rate range of 1 Hz to 666 Hz for ~60 USD. It would be fun to watch , if nothing else. Might even be informative!

Yeah, I’m here as well. There goes the neighborhood, eh?:) It’s too bad it would be tricky with two diaphragms, because it would be interesting to try keeping your inner tube diaphragm tensioner as part of a panel so you could easily change just the tension and measure what happens. In any case...

Great work, as usual, Joppe! While watching your videos I was struck by how taut your membranes are. As I’m sure you know, with electrostatics, tension is necessary so the diaphragms aren’t pulled into the stators even with no signal. That's not a concern for your magnetically driven panels, so...

For those interested in using Python, I just found this source of spherical harmonics tools. I’m not sure if they do anything NTK hasn’t already worked out. Few

It looks to me like the spherical harmonic transform is the same as the fit to the angular components of the sound field. it doesn’t include the radial component, or the field separation. At least that’s my impression. Few edit: Maybe posted prematurely. I now see that later in the video he...

In case you might consider diy: https://www.diyaudio.com/community/threads/are-there-any-good-diy-planar-kits.317425/ I marvel at my planar magnetic desktop speakers every time I fire them up. Few

“Should have thought of that myself..." Nah…that’s what audio friends are for! Bummer the option is not part of Octave. Few

For help with Octave, you can search online for Matlab's generally excellent help. Find "round" here. The bottom line is the 4 dictates the number of digits the first argument should be rounded to. More specifically, if N is the second argument: N > 0: round to N digits to the right of the...

My LabVIEW program isn't ready for use in its current state. I'll have to dig it out and remind myself of its status. I think that when I paused development I had one bit of code to move stepper motors and an independent bit of code that does the acoustic measurements. They'd need to be put...

Good to know. Thanks. I actually wrote a program in LabVIEW that I can run from the Mac. It doesn't provide lots of ways to view the measurements, but it works well for acquiring the measurements. I made the same measurements with my program and with REW and found things match as expected. If I...

This version is a hybrid of the one in the Ebay Openbuild link Mark provided, and the interdigitated belt system I mentioned previously. Nice and simple, and very few parts! I wonder how much play there is in the position. Few

The only Windows in my house let in the light, so ARTA won't be a solution for me. I've tried several schemes for running Windows software on a Mac, and made it work, but I don't enjoy the experience. I did come across this YouTube video on Erin's Audio Corner. He goes into a bunch of detail...

Yeah I considered a threaded rod of some sort (acme, ball screw, etc.) but I’m assuming the vertical range of motion has to be pretty big. As I write that, though, I don’t have any firm numbers to base that on—what vertical range do we actually need? In any case, a large range of motion would...