Surprisingly or not, with the Minmeh I can hear the comb-filtering pattern dave has often posted. From ~3m away slightly off-axis ~0.4m, ear angled for maximum acuity, the sweet spots are ~10cm apart shifting (head) horizontally, or ~20cm forward/back. At these nodes the music is more open and realistic, presumably due to very high frequency present; away sounds a (very) little duller, less micro-dynamic contrast. I first noticed this when, each time I thought it sounded A+, with a head-sway it no longer was.
How to reduce horn/mouth/throat diffraction combing? VHF should be throat?
Combing is eliminates completely if the spacing between 2 drivers playing the same frequency are a quarter wavelength centre-to-centre. As distance increases combing gets worse. Given the spacing you have XO would need to be very low and th etweeter likely can’t go near low enuff.
Toole'’s work suggests it is not near as audiable as they look. From Taylor: http://p10hifi.net/planet10/TLS/downloads/taylor-line-array.pdf
dave
How to reduce horn/mouth/throat diffraction combing? VHF should be throat?
Combing is eliminates completely if the spacing between 2 drivers playing the same frequency are a quarter wavelength centre-to-centre. As distance increases combing gets worse. Given the spacing you have XO would need to be very low and th etweeter likely can’t go near low enuff.
Toole'’s work suggests it is not near as audiable as they look. From Taylor: http://p10hifi.net/planet10/TLS/downloads/taylor-line-array.pdf
dave
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Happy to report issue resolved with Art's diagnosis:
Then the HF driver's output will diffract across the large flat square surface around it, the diffraction will reflect off the horn walls, the multiple arrival times from those reflections...
Pretty good now, ~35° horizontal coverage of flat FR to 12khz that I could hear (Faital HF108 exit angle being 31°). My cost was ahem $220 for eight used drivers (CD, Faital-inside, 12" Aura) plus significantly more than that for the Jantzen aircores and silver zcaps which I reuse for diy-of-the-day.
If this is what your MEH horn looks like:
Then the HF driver's output will diffract across the large flat square surface around it, the diffraction will reflect off the horn walls, the multiple arrival times from those reflections...
Pretty good now, ~35° horizontal coverage of flat FR to 12khz that I could hear (Faital HF108 exit angle being 31°). My cost was ahem $220 for eight used drivers (CD, Faital-inside, 12" Aura) plus significantly more than that for the Jantzen aircores and silver zcaps which I reuse for diy-of-the-day.
