klipsh forte III purchase

Can anyone explain the difference in sound between the Forte III vs the Cornwall III and the Hersey III (the models above and beneath the Forte III)? I don't have a dealer near :-(.

I would strongly recommend you bring some of your favorite music to a Klipsch dealer and spend some "quality time" listening to them.  I used to sell Klipsch, had no reservations about doing so, but sometimes customers who took some time to listen found the brightness was fatiguing.
Our ears are all different, so this might not be the case for you.
All the models you mention have very high efficiency and great dynamics.

@lak

The Heresy and Cornwall share the same MF and HF compression drivers, but the Cornwall is front-ported with a 15" woofer while the Heresy is sealed with a 12" woofer. Because of that (and the larger cabinet volume) the Cornwall has an extra 24hz of bass extension.

The Forte III is the newest model in the lineup, and though it’s priced under the Cornwall, it’s using the newest compression drivers and has the redesigned horn/waveguide for smoother off-axis performance and better controlled FR. If you look at the Klipsch specs the Forte III’s midrange compression driver covers from 650hz to 5.2Khz while the Heresy and Cornwall use their midrangers to cover between 800hz-5Khz (Cornwall) or 850hz-5Khz (Heresy) so that new horn/waveguide is allowing the new midrange compression duty to take on a larger role.

The Forte III uses the 12" woofer but it has a 15" passive radiator in lieu of a port. It achieves bass extension almost to the same level as the Cornwall because of that.

If I were a betting man I’d imagine we’re going to see a Heresy IV and Cornwall IV in the next year or two featuring the new compression drivers and midrange horn/waveguide from the Forte III. Right now the Forte III seems to have the best tech in the series.

I think Klipsch should stick with their "Heritage" models but offer "SE" models with modern materials. Basically great designs but need some current tech upgrades.

@tutetibiimperes, thank you...