The Klipsch Conundrum

[Gigantic]

here's the gist with the Super Heresy mods:
start off with a Heresy 1, with the type E network and birch cabinets.
there are a few variations, largely dependent on woofer selection and cost.

Version 1 has several possible woofers that operate within the same, general Thiele/Small parameters (or close enough): Eminence Delta Pro 12A, Klipsch k42is the original, @THD+N found that the Celestion TF-1225 works very well for not much money and the Dayton Audio PA 310-8 is another affordable option. Version 2 uses an Eminence Kappalite 3012HO, which possibly produces the best results.

the squawker stays the same, although many recommend damping the mid horn with bitumen or rope caulk to reduce the resonance and ringing.

the tweeter is replaced with @Daveintn 's sMAHL tweeters- this is what makes them "super". the sMAHL provide exponentially better dispersion, transient response and are an order of magnitude better than stock.

lastly, one adds a 4" x 4-1/2 port in the rear, in a lower corner. Many use the B52 4" x 4-1/2" port, but 4" schedule 40 PVC plumbing pipe will work, too.

one additional option is to replace the 2µf capacitor feeding the squawker with a 4µf cap. it's not necessary, but it lowers the crossover from 700Hz to 600Hz and is partly why Claude called his creation the "Baby Cornwall."

the end result is substantially better midrange response, with the added bonus of bass extension down to the lower-mid 40Hz range. There are those who say that the popularity of these mods led to the development of the Heresy IV, which delivers similar performance, although the sMAHL is a much better tweeter. I would advise to resist the temptation to do just part of the mod series: adding a port, but keeping the stock woofer will increase the bass response, but it will be flabby and indistinct. skipping the tweeter and leaving the OEM in place is also advised against: I can't overstate how terrible the OEM piece is and how much the sMAHL improves everything. The price of the sMAHL gave me pause when I built my first set of Super Heresy and I had some trepidation in shelling out that much money- I couldn't believe that they'd make much difference, but man was I ever wrong! they're the most critical part.

If you search "Super Heresy" here, there are several threads detailing various build versions and reactions. There are also two massive threads over at the Klipsch community by @ClaudeJ1 detailing the first Baby Cornwall/Super Heresy build, complete with measurements and side chatter, as well as version 2.0, that uses the Kappalite woofer. I recommend reading them, but please, do not respond to the threads- it is forbidden to discuss modifications over there these days and there is a real chance that those threads could be capriciously nuked.

@Dave MacKay put together a doc with all of the versions and variants below. you may find it useful.

Heresy 1 to Super Heresy v2 instructions

Good points about lowering the inductance in the Xover when using the Dayton woofer. I'm also working on a version that will have lower bass, but it will be more than just a woofer swap like with the 1.0 and 2.0.

www.audiokarma.org

 

[THD+N]

The TF1225 sounds better in the ported Heresy than the K42 IMO. Don’t get me wrong, the K42 is a beast, but it may be too much of a beast. The TF1225 sounds like a mini ported LaScala… the bass is that good and articulate.

 

[twiiii]

The MK 4 Hersey is a big improvement over the older models. Its ported extending the bass a bit. But if I had the room I would rather have Cornwalls, too Especially the MK 4. Especially if you use the system in the Stereo mode, which will on some AVR's disconnect the Subwoofers. They are really a big improvement over the previous renditions. Of course I would want the latest Hersey mk 4 for the center channel as it is the most important speakers for a HT system. Having 3 identical speakers up front is always the preferred choice. But for me as I value Stereo sound first and HT second, the two Cornwall MK 4 would be my choice. The latest Heritage Klipsch speaker are so much improved over former models. How is that even possible? Well it is. How a Cornwall IV can compete with the very expensive JBL DD67000 for a fraction of the cost is just amazing. Notice I said competes with not equals. But for most folks the Cornwall is a real bargain compared to other speakers of that caliber. Everyone complains about the new Heritage Klipsch prices. But compared to European, American and British speakers costing close to 70 thousand a pair the Cornwall competes very well set up properly using advanced electronics. You can't expect a Cornwall to compete using Ho HUM electronics when other speaker companies are using the best out there to demonstrate their efforts.