I agree, Joseph Audio speakers sound exceptional, and the build and finish is superlative.
One reason is that he uses the ’Infinite Slope’ crossover, originally patented by Richard Modafferi for the JSE Infinite Slope speakers. From his site:
https://www.josephaudio.net/prism-technical-specifications
"Crossovers: Asymmetrical Infinite Slope Crossover at 2.5 kHz.
Constructed of specially selected components, Each individual network is precisely adjusted, resulting in a virtually perfect match to the original prototype.
The steep filter slopes ensure good acoustical behavior in the crossover regions, with a minimum of acoustical interference, along with low distortion and wide dynamic range. Driver acoustic responses are in-phase throughout the crossover regions."
I owned and loved the JSE Model 2’s for years, these are sold but the listing shows them well
https://holthill.com/products/jse-infinate-slope-model-two-extraordinary-speaker-system
AI Quickie about Richard Modafferi
(I suspect AI is not giving Jeff Joseph his due in the design of his speakers).
"Richard Modafferi is a renowned audio engineer and inventor best known for designing the McIntosh MR77 and MR78 tuners while working as a Senior Engineer at McIntosh Laboratories from 1968 to 1974. He is also credited with developing the famous "Rimo" filter, the Infinite Slope Crossover technology, and Phase Shift Bass Loading, for which he holds United States patents.
After leaving McIntosh, Modafferi founded Modafferi Acoustical Systems, Inc. and later served as an independent consultant to Audio Classics, where he personally performs repairs, modifications, and updates on vintage McIntosh tuners to exceed their original performance limits. He also designed the Joseph Audio speakers and invented the Infinite Slope crossover, which minimizes wave interference in multi-driver loudspeakers to improve off-axis response."

