@oldhvymec --
So 101 on speaker building for me is know what your talking about..
My terminology may not be the as eloquent as the word salad connoisseurs, BUT my personal observation and understanding of "bass distortion" seems to conflict with most of "New way" of thinking..
FIRST; PHASE PLUGS are the ONLY way to decrease bass distortion properly on all round cone drivers "second wave". OR Don’t use cone drivers, OR Don’t use large surface area drivers.. The is NO OTHER WAY...
I’m far less complicated here using large coned, high efficiency drivers presently from ~615Hz and down - "second wave" be damned; (per channel) two of them ported (~85 to 615Hz) and the last one is loaded in a tapped horn to cover the rest of the range down to some 20-25Hz. At SPL’s that shakes the air and surroundings quite violently the TH woofer moves or rather vibrates about a mm at most (it can move up 18-20 mm peak to peak), while the main speaker dual woofers don’t visibly move at all (less cone movement means less inertia build-up, and more cone area means better air coupling). For all intends and purposes the 15" woofers here all stroll along at levels that are viscerally felt. The compression driver and large horn (more than 5 sq. ft. mouth area) that covers the remainder of the frequency span from ~615Hz on up sports a 111dB sensitivity, and rarely see more than a single watt from the amp feeding them actively. They’re cruising while I’m potentially bruising, if you get the picture. In both cases distortion is vanishingly low, despite claimed 2nd waves and stated high compression ratios - even approaching decibels that are ear shattering in a home environment.
If I were to be discouraged by notions not to use large diffraction horns (much) deeper than 12" in a home environment nor large coned HE woofers due to second wave distortion, I’d be an important experience so much poorer. As an example quite a few people rave about the waveguides used in JBL’s more recent monitors, and yet compared to an older and much(!) larger EV diffraction horn with its landmine big CD they sound small and almost malnourished - the 4367 waveguide indeed mode-y and strident - and less relaxed and full. Commercially large size doesn’t sell, but I’d go so far to say that with horns in particular it’s the one ingredient that makes a substantial difference. There’s no working around that, even if it means refining flare geometries from a smaller size - period. Indeed, the larger the horn the less it sounds like a horn, or like two friends, both audio buffs, who heard my EV system the other day, said: "It sounds like ESL’s on steroids."
Lot’s of reasons not to go big with speakers, pro segment not least, but I’d say most of them are preconceived rather than coming from actual experience. Just my $0.02..
