Due to waveguide size, CTC (center to center) is relatively far apart than non-waveguide speakers. But more important factor is CTC wavelength at the crossover point. We have λ/2=CTC at crossover point.
This is quite close distance for a 2 way non-coaxial speaker. You can use it as nearfield monitor at 1M, even at closer distance too.
Thanks for sharing such a great articles.
I searched your another post too. It was helpful too. (
https://www.audiosciencereview.com/...-and-far-field-definitions.23841/#post-801349)
When I come back the office, I’ll check the response again. It will be a good evidence to specify proper minimum listening distance, though I think already it is acceptable to listen at 1m and even closer.