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Super Heresy 1 (Baby Cornwalls Mod.)

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So far, all I can say it totally sounds even better than the Ported Box model suggests. Slamming bass, better treble and midrange detail, and all based on the "domino effect" of a Klipsch K-42 woofer upgrade. This is a pretty simple and straightforward upgrade to the sound of a Heresy, which makes it sound more like a Cornwall, but not as low, with similar efficiency gain. It's not cheap, just GOOD. Also a killer new tweeter and Xover mods. More later. As of today, 5/24/2017, I"m amending my comment about the tweeter. If you have good K-77 tweeters, you can leave them in, but plan on an incremental/eventual replacement! This makes the modification WAY less expensive than immediate tweeter replacements. You will still get bass extension, more midrange detail, and use about 1/2 the amplifiers power, since your efficiency goes up by 3 db or so........Claude.


I'm just curious to know how many Heresy 1 and 1.5 owners might be interested in doing this for themselves, here are some indoor measurements of the original Heresy 1 to show actual curves of the improvement and why. The curves clearly show flatness of the B&C DE-120 tweeter with @Dave A sMAHL lens vs. the K-77, and the overall increase in smoothness and higher efficiency above 150 Hz., which is where the Klipsch K-42 woofer does it's thing (GREEN). The efficiency is i the 99 db/watt range, depending on where you do your measuring vs 96 for a Heresy with a K-22. You can see having the port about 4 feet away from the walls in the first 1/3 octave smoothed curves still puts out lots of bass down low.


In the second curves, I jammed both in corner on floor, where the full effect of the Super Heresy port was essentially blocked a bit, while the boost occurred in the same area as the H1. Even though the output was lower on the H1, I lined up the bass area to show the gains in the mids and high end, especially the lack of rolloff with the new tweeter. Basically, how far you put either one of them from the corner has an effect on the response, but I think having the Super Heresys out of the corners a bit to lower the 90 Hz. peak and open up the lower bass from the port helps flatten things out a bit. The other thing one can do is get a used Onkyo 709 receiver cheap and let Audyssey totally smooth out the room's peaks and dips, especially below 300 Hz. but you need optimum placement from corner first if possible.


Trying these in my bedroom. The do growl on those low notes now that they are slightly forward of the walls in corners, give the port room to do it's thing. Amazing slam........very Cornwall-like that way. Check out the FR plot in my room, holy cow!! A Heresy that goes below 30 Hz. Mike was 8 ft from speakers 8 feet apart and about 1 foot out of corners so the reflex port could "breathe."


After going back and looking at my "E" network modifications, as outlined in later post, I basically just created a Cornwall "B" network out of it, except it's got reverse polarity for the mid and tweeter connection. Interesting co-incidence, since it sounds like a "baby Cornwall" with the new woofer drivers. So if you find a Cornwall "B" schematic on these forums, that's the one, you just have to reverse the connections to the horns. You may find a used one on Ebay, the you just have to refresh the capacitors or use it as is in the meantime. Or you may want to create a Cornwall B2 or B3 network in case you prefer that sound, but either way the woofer and port with foam stuffing will do the same thing in the bass. Only the midrange will be affected by the B2 network, which you can find elsewhere on this site.  But if you can find a Heresy C,D, E, or E2 network to modify, then you will have to do a little soldering, yes.



In no way am I trying to insinuate that this "super Heresy/baby Cornwall" is better than a Cornwall, which would trounce it in the bass department. But having a beefier woofer and a port brings the efficiency up to the same level and the ROOM itself picks kicks up the bass to a satisfying level, not the the speaker. It a combination of the two, which any speaker would have to deal with, not just this one. See post #30. For now, pay particular attention to the third (Purple) curve, which is the actual sweet spot response in my small room!!



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OK, ladies and gents, here's the measurements. In keeping with my prior methods in the Quarter Pie build threads, I post the measurements showing performance BEFORE I show you how to build, or modify in this case.

I did 3 types of measurements. All levels were set with pink noise to match for each measurement.

The GREEN was the speaker out into the room on pedestal about 6 feet away from 2 walls with the microphone in the middle of the front speaker 1 Meter away.

The RED was a measurement of the speaker rotated 180 degrees front to back with the mike at the bass PORT from 1 foot away with a -4.7 db offset to get the same curve level position in the plot.

The final BLACK curve was the speaker on the floor in the corner.

I included the "no smoothing" as well as the 1/3 octave smoothing curves for greater clarity of what is going on.

The rear bass port starts doing it's thing at about 150 Hz. all the way down to about 30 Hz. as you can see from the crossing of the RED and GREEN curves.

If you look at the corner placement, you can see what it doe to the bass below 100 Hz. and that, like the textbook says, the room has very little effect above about 300 Hz.

Please note how smooth and flat the fantastic new tweeter is.


You will be blown away by how much bass you get out of that "miniature" Heresy and by how much clearer, crisper, and cleaner it sounds this way. You might even like it better than a Cornwall or Chorus, who knows.

I would suggest that they are placed about 6-18" out of the corner. Most of the bass will be coming out of the port, so this is how you fine tune the overall bass response, by placement. Just use your favorite bass test recordings and your ears will tell you.

But you must have them in corners for best overall performance, if possible. At the very least, they need to be close to a wall. Also, the efficiency of the woofer is higher, so it will play louder as well as lower or require about 1/2 the power you had before to do the same job in the mids and highs.

Edited by ClaudeJ1
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I will present this mod in incremental steps:

For the bass improvement: order this flared port (cheap) https://www.parts-express.com/speaker-cabinet-port-tube-4-id-x-4-l-flared--260-403 and cut the appropriate size hole in the rear bottom corner.  

Remove the K-22 woofer and replace with K-42-K, ordered from Klipsch parts or an Eminence Delta Pro 12A from Parts Express if you don't have a serial number on the back of your old Heresy Cabinets. You should use 8 screws per woofer instead of just 4, since the magnet is huge on the K-42 and very heavy. The woofer weighs almost 20 lbs. and more screws are cheap insurance. You will need #10, 1 1/4" screws since the cast woofer frame is thicker than the K22 you are removing.

Put foam on all surfaces inside the cabinet to absorb and keep the rear generated midrange stuff from bouncing around.

You will need to increase the K55 idrange and tweeter output by 3 db to match the more efficient woofer.

I have an "E" network, so I changed the first capacitor going to the autoformer from 2 uf. to a 4 uf. You can buy 3 new caps, or just solder two 2 uf. capacitor in parallel, when you buy 6 total (which will give you 4 uf) on top of each other there now if your network was refreshed. If not replace those old fat original capacitors with the following: https://www.parts-express.com/dayton-audio-dmpc-20-20uf-250v-polypropylene-capacitor--027-414

Unsolder the wires from terminal 2 (K55V midrange position) and 3 (tweeter position). Now solder the midrange wire that was on terminal #2 onto #3. Those of you with "D" networks should reverse the leads going to the K55V driver.

Take the K-77 tweeter wire and solder it to terminal #4 on the autoformer. This should have been unused before.

For a tweeter that stomps a K-77 and is worth every penny, do what I did to get those sweet, flat tweeter portions of my curves and superior definition on cymbals and harmonics of all instruments.

Go to @Dave A for the B&C120 driver and his sMAHL 2.0 tweeter lens, or for a cheaper alternative that still fits, get the DE-10 (after measuring and using both, I prefer this over the more expensive DE-120).

So now after 6 years, 1 month, and 2 days, I offer the following updates:  Karlson3 and Wirruna got me thinking about possible variations that are easier and cheaper, that simply make good/bad/different compromises in the results. Only YOU know what you like best so I will give a bit more room to PLAY with different values. In other words, a bigger sandbox that the above modification demands. I've come to terms with people who want more wiggle room. Pragmatic vs. Dogmatic, so here goes:

1) First and foremost,  I modified a Heresy "E" network, to have 4uF capacitors for the midrange and tweeter (double the original 2 uF value), it ended up looking like a Cornwall "B" network EXCEPT with the POLARITIES on the mid/tweets were REVERSED in the modified E (vs. a pure B, which they are not). So if you bought a Cornwall B network, just reverse the polarities if you want.............all 6 db per octave (First Order), but it's your call on the phase response you end up with.


As you will see, depending on which woofer you end up using, your ROOM, how far the speakers are IN/OUT of Walls/Corners, your personal taste, etc. etc. you may want to TWEAK your own variables to your TASTE, ok? For the woofer section, the original 2.5 milliHenry Klipsch Iron Core choke worked fine to my ears. Remember, this will control the Midrange Frequency Rolloff as it hands the sound over to the Midrange Horn. My using the original woofer inductor was part convenience/laziness, and it measured/sounded good to ME. But it was for a Klipsch K-42 or Eminence Delta Pro 12A woofer. As other woofer options are presented down below, you have the freedom to try NO INDUCTOR, up to 4 mH to choke off the midrange portion of the woofer. If you choose Second Order Network, similar to a Cornwall B2, you can add a parallel capacitor from 20-60 uF on the woofer, which will yield a 12 db/octave rolloff which will be clearly audible since "the midrange is where we live" according to PWK and others. Improved midrange was my original reason for the woofer change to begin with but ported bass was also a bonus. You can also vary the Capacitor values on the Midrange and Tweeter sections from 1 to 4 uF (micro Farad) to shift the roll UP frequencies on the low end of the horns. Again, the audibility of this may be questionable and only those who measure may SEE a difference from small changes, like 2 uF vs. 2.2 uF, etc. Between messing with these values, port length, polarities, etc. you could be messing with this stuff for a year and never be satisfied. Who am I to limit the Tweakers' Playground to a small sandbox!!


2) If your are going to play with all these variables, then you may as well be able to use a Crites Autoformer with fine 1 db steps instead of crude 3 db steps in the Klipsch T2a. WARNING!  This could extend your playtime for another year. LOL.


3) Adding another variable to FIXED box volume of a Klipsch Heresy, there's a woofer choice that someone may wish to try. I still think the original K-42 or Eminence Delta Pro 12A is the best (most expensive too) choice for the best MIDRANGE response (high BL product AND low voice coil inductance), the Dayton PA 310-A is an economical substitute at about half of the price. I guess you need to choose whether to keep the profits in the USA or send some to China, which is beyond the scope of this text. I want to point out that this woofer simulated curve in Black is superimposed over the the original K42 in Gray. You can see a slight bass extension, but with less efficiency and a rolloff that begins 300 Hz. sooner. I hope to be working on a Super Heresy 2.0 soon and I may end up trying this woofer. It's possible that it may be used WITHOUT any inductor since it has almost twice the inductance of a K-42 that is partially responsible for the early midrange rolloff. There's another Klipschead from another continent that will be using this woofer. I hope he posts his results and measurements here for all to see and read his impressions of the sound quality. I just want to remind everyone that room SIZE and speaker PLACEMENT, and Listener POSITION will more RADICALLY change the bass response than these simulate curves ever could convey. Always keep that in mind when you do this stuff.


Also see the latest Version 2.0 of this mod:



Cornwall B network.gif.jpg

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Interesting Heresy mod.

Maybe you could get by without a subwoofer with this version.

Not really, no. Most of the improvement is in the midrange anyhow. The bass is just a bonus.

You need the port because the high BL woofer makes the bass thin to make better midrange at 700 Hz., so the port makes up for it. I'm working on possible further tweaks, but this is a good start.

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I like experimentation. :)

I like high BL woofers, which is what EV and JBL have. They cost more $$ because they are more expensive to make. They have better, sharper transient response, but they give up bass in the process, so it only made sense to model it in Bass Box first to make sure I could at least get as much bass back as a vanillla Heresy. Turns out it's even better and more powerful. I will run curves in the same spot of a vanilla Heresy tomorrow for comparison. I'm confident that my "Super Heresy" will win. It's not just curves, it has to sound good too, which it does.

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Remove the K-22 woofer and replace with K-42-K, ordered from Klipsch parts or an Eminence Delta Pro 12A from Parts Express if you don't have a serial number on the back of your old Heresy Cabinets.

Could one use the Eminence Delta 12lfa instead of the Pro 12A? Close enough?

......Delta 12LFA

Power Rating Watts 500W Music Program 1000W Resonance 51Hz Usable Frequency Range 44Hz-3kHz Sensitivity 94.6 Magnet Weight 56 ounce Gap Height 0.375", 9.53mm Voice Coil Diameter 2.5", 63.5mm THIELE and SMALL PARAMETERS Resonant Frequency (FS) 51Hz DC Resistance (Re) 6.06 Coil Inductance (Le) 1.45mH Mechanical Q (QMS) 7.28 Electromagnetic Q (QES) 0.51 Total Q (QTS) 0.47 Compliance Equivalent Volume (Vas) 67.9 liters / 2.4 cu.ft. Peak Diaphragm Displacement Volume (VD) 243cc Mechanical Compliance of Suspension (CMS) 0.19mm/N BL Product (BL) 14.1 T-M Diaphragm Mass Inc. Air load (Mms) 51 grams Efficiency Bandwidth Product (EBP) 100 Maximum Linear Excursion (XMAX) 4.8mm Surface Area of Cone (SD) 506.7 cm2 Maximum Mechanical Limit (XLIM) 13.5mm MOUNTING INFORMATION Recommended Enclosure Sealed 19.8-28 liters/0.7-1.0 cu.ft. Vented 25.5-102 liters/0.9-3.6 cu.ft. Overall Diameter 12.03", 305.5mm Baffle Hole Diameter 10.95", 278.1mm Front Sealing Gasket fitted as standard Rear Sealing Gasket fitted as standard Mounting Holes Diameter 0.25", 6.4mm Mounting Holes B.C. D. 11.59", 294.3mm Depth 5.35", 136mm Net Weight 11.8 lbs., 5.4 kg Shipping Weight 14 lbs., 6.4 kg MATERIALS OF CONSTRUCTION Coil Construction Copper voice coil Former Polyimide former Magnet Composition Ferrite magnet Core Details Vented and extended core Basket Materials Pressed steel basket Cone Composition Paper Cone Edge Composition Cloth cone edge Dust cap Composition Solid composition paper dust cap

Edited by cheric
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Could one use the Eminence Delta 12lfa instead of the Pro 12A? Close enough?

Not really. It would require a different box size and tuning. In fact you'd be better off leaving it sealed. All I can say is try it with a simple swap. You won't hurt anything. Also, the efficiency is less so you wouldn't want to change the crossover in any way, although I would highly recommend the Super Tweeter change, which is totally WOW. Both just a simple swap.

Edited by ClaudeJ1
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  • ClaudeJ1 changed the title to Super Heresy 1 (Baby Cornwalls Mod.)

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