pkeller

Hi: It's been a while since my last post and this may seem weird, but..... try your Heresy's on their side with tweeters toward the middle (each other). The improvement in soundstage and imaging is substantial. Get out your most familliar, naturally miced, recording and angle the horizontal Heresy's directly facing your listening position. If your audio system and your listening habits have been crafted to maximize imaging, you will not change them back to the verticle position. It will cost you nothing to try and is totally reversible. Let us know what you think after you've given it a try. Paul Keller

Hey Gang: Could somebody please send Al K. a pair of beat, up but functional, first generation Heresy's (E-network)in trade for some of his crossover work. Looks like he needs a pair of Heresy test platforms. There has to be some K-horn, Belle, LaScala, Cornwall owners out there with a set of beat up Heresy's their not using. With the potential increase in sales, Al could probably use a stunningly beautiful assistant as well. Paul K.

Sorry about the multiple posts. I keep getting messages that my posts are not being accepted. Obviously not true. Paul

I had thought the same thing. The problem is that the T/S perameters of the woofer are designed for a sealed enclosure. The balance of bass v/s mid would not have the same ratio of response. At higher volume levels, the sealed design of the Heresy depends on internal compression and rarification of internal atmosphere. It would be risky and non-linear to drive the woofer "unloaded" at such excursion levels. A tuned port might be used to augment the low response if the Thiel/Small measurments were known. This would limit low frequency excursion if the desired tuned frequency is close to the acceptable perameters of the woofer. Still, there would be all kinds of non-linearities in response. Better towork up a new crossover design using Klipsch tweeter and midrange and a more compliant "but efficent" woofer. Good luck: Paul

I had thought the same thing. The problem is that the T/S perameters of the woofer are designed for a sealed enclosure. The balance of bass v/s mid would not have the same ratio of response. At higher volume levels, the sealed design of the Heresy depends on internal compression and rarification of internal atmosphere. It would be risky and non-linear to drive the woofer "unloaded" at such excursion levels. A tuned port might be used to augment the low response if the Thiel/Small measurments were known. This would limit low frequency excursion if the desired tuned frequency is close to the acceptable perameters of the woofer. Still, there would be all kinds of non-linearities in response. Better towork up a new crossover design using Klipsch tweeter and midrange and a more compliant "but efficent" woofer. Good luck: Paul

Wow: I just saw Al K's schematic of the Cornwall B2 network and was surprised to see that 245uH choke across the tweeter poles. That has the effect of shunting off lower signal to ground and lowering some of the tweeter level. The choke is after the tweeter cap so the total signal resistance through the choke could be high and still reduce the tweeter level a significant percentage. Does anybody know the resistance of the choke? Klipschguy, this could explain your Heresy's tweeter level being closer to your Cornwalls once they were reduced 3db. What I'd really like to do is get a pair of chokes to play with. It will offer better tweeter protection with it's steeper cutoff slope as well. Probably needed with the higher level of output in the 101db Cornwall's Paul

Wow: I just saw Al K's schematic of the Cornwall B2 network and was surprised to see that 245uH choke across the tweeter poles. That has the effect of shunting off lower signal to ground and lowering some of the tweeter level. The choke is after the tweeter cap so the total signal resistance through the choke could be high and still reduce the tweeter level a significant percentage. Does anybody know the resistance of the choke? Klipschguy, this could explain your Heresy's tweeter level being closer to your Cornwalls once they were reduced 3db. What I'd really like to do is get a pair of chokes to play with. It will offer better tweeter protection with it's steeper cutoff slope as well. Probably needed with the higher level of output in the 101db Cornwall's Paul

Wow: I just saw Al K's schematic of the Cornwall B2 network and was surprised to see that 245uH choke across the tweeter poles. That has the effect of shunting off lower signal to ground and lowering some of the tweeter level. The choke is after the tweeter cap so the total signal resistance through the choke could be high and still reduce the tweeter level a significant percentage. Does anybody know the resistance of the choke? Klipschguy, this could explain your Heresy's tweeter level being closer to your Cornwalls once they were reduced 3db. What I'd really like to do is get a pair of chokes to play with. It will offer better tweeter protection with it's steeper cutoff slope as well. Paul

Wow: I just saw Al K's schematic of the Cornwall B2 network and was surprised to see that 245uH choke across the tweeter poles. That has the effect of shunting off lower signal to ground and lowering some of the tweeter level. The choke is after the tweeter cap so the total signal resistance through the choke could be high and still reduce the tweeter level a significant percentage. Does anybody know the resistance of the choke? Klipschguy, this could explain your Heresy's tweeter level being closer to your Cornwalls once they were reduced 3db. What I'd really like to do is get a pair of chokes to play with. It will offer better tweeter protection with it's steeper cutoff slope as well. Paul

Wow: I just saw Al K's schematic of the Cornwall B2 network and was surprised to see that 245uH choke across the tweeter poles. That has the effect of shunting off lower signal to ground and lowering some of the tweeter level. The choke is after the tweeter cap so the total signal resistance through the choke could be high and still reduce the tweeter level a significant percentage. Does anybody know the resistance of the choke? Klipschguy, this could explain your Heresy's tweeter level being closer to your Cornwalls once they were reduced 3db. What I'd really like to do is get a pair of chokes to play with. It will offer better tweeter protection with it's steeper cutoff slope as well. Paul

Wow: I just saw Al K's schematic of the Cornwall B2 network and was surprised to see that 245uH choke across the tweeter poles. That has the effect of shunting off lower signal to ground and lowering some of the tweeter level. The choke is after the tweeter cap so the total signal resistance through the choke could be high and still reduce the tweeter level a significant percentage. Does anybody know the resistance of the choke? Klipschguy, this could explain your Heresy's tweeter level being closer to your Cornwalls once they were reduced 3db. What I'd really like to do is get a pair of chokes to play with. It will offer better tweeter protection with it's steeper cutoff slope as well. Paul

Actually, a pair of beat up non working but complete Heresy's gets you the tweeters and mid horns for the Cornwall and Belle. Finding a compatible woofer will be the tricky part. If you knew the Q measurments and SPL @1x/1m of the Klipsch woofer version, you could find something close using the LDSG. http://www.snippets.org/ldsg/ You may need to add a new diaphram or two and of course, purchase parts for the crossovers. The rest is securing plans for your desired model. I personnaly would like the early Cornwall version with verticle horns. Does anybody know of a source of plans for these? pkeller@ix.netcom.com

Klipschguy: I'm really at a loss as to why your tweeters are excessively bright. Most of the modifications you site are for the "mid" horn in the Heresy's. My K77's being alnico, and yours ceramic may explain part of the difference, but not to the extent you describe. I was thinking that possibly you have mid drivers that have an extreemly agressive 9khz return resonance. Since the tweeter takes over at 6khz, this would add substantially to the perceived tweeter level. A large 9k spike in response from a non-linear region of the mid driver could introduce a secondary harmonic that feels like your sticking a pencil in your ear. Not every Atlas mid driver resonates at 9khz, so it stands to reason that some may resonate a "great deal" at 9khz. When you reduced the tweeter level, it could have brought the overall 9khz region more into balance. I am not at all confident that this is what happend. It's only a theory. In any case, you may want to try the P-Trap before any further crossover mod. I know that my Heresy's became a lot more civilized when I added the P-Trap. It could be that the return resonance at 9khz is at a fixed volume and becomes less of a factor in the more efficient Klipsch designs using the Atlas mid driver. Dang I hate to be baffled like this. Keep us posted. pkeller

I've been thinking that the bright voicing of the Heresy's might be due to amplification. Heresy's were designed when tube amplifiers were the standard. Tubes have a softer cleaner high frequency presentation ("generaly speaking", no flames needed) and a more pronounced mid response. I am using tube amplification for evaluation and testing. This might explain our difference in tap location needed. Especially if you using solid state equipment more than about 15 years old. SS equipment, including pre-amps were pretty bright back then. What are your driving components? Paul Keller

I doubt the Aerovox caps have changed much over their 26 years of life. I don't know of any source for them presently. Even if you could find NOS Aerovox caps, their age alone will make them close to what you already have. The miniscule current used by the mid and tweeter in 101db speakers is really not a degrading factor. The big reason to use premium modern film caps is to attain superior detail and extension in the high tones. There is no question that the Northcreek Zen 2.0uf caps have greater transparency than the stock caps. This comes at the loss of some smoothness that the mid squawker requires. For this reason, I bypassed both the 2.0's with .1uf Northcreek Crescendo caps. This smoothed things out a great deal without loss of the transparency or extension. The P-Trap also requires some modification. I used Zen 3.0uf but found that it too needed bypassing. I only had a Harmony (again Northcreek) .22uf at hand, so I used it with good results. I'm going to try Crescendo caps for the P-Trap in both base and bypass mode. I hope this adds to the transparency even more, but at this point I'm fishing for even better results. I should say that Northcreek caps behave much differently than most all other caps on the market. Normal metal film caps will become bright and hissy when used in bypass mode. This is not at all what Klipsch networks need. Not so with the three lines of Northcreek caps. There is also concern regarding the addition of capacitance value when bypassing. Making a 2.0 into a 2.1uf is only a 5% change for the mid horn and 10% for the tweeter and not noticable given the gradual 3db design slope of the stock "E" network. As for moving the mid and high frequency taps on the autoformer, I have avoided trying this as it changes the impedance of the system a slight bit, but probably not a significant amount. This network sounds well balanced with the stock locations used. If anything, I would lower the squawker 3db, but that might be a bit too much, so for now it will stay. You do have my curiosity tweeked, though. My Heresy's still sound like Klipsch designed, but with a higher livel of surrounding ambiance and detail. All of the above has been done without tearing into the stock Klipsch networks. I can reinstall the stock boards in a few minutes if I desire. This is only insurance should I decide to sell the Heresy's some day. But I don't see that happening any time soon. Paul Keller