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Heresy upgrade with great imaging, smooth midrange and low-end SLAM!!


Antone

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davidcl,

I believe that the "E2" is better, since Klipsch evidently thought it was worth changing, and adding parts to, the "E". Also, the "E2" not only reduces the overall power (by 9 dB) going to the squawker (via the T2A autotransformer, as in the "E"), but also, only the "E2" uses another capacitor (33 MuF) to block frequencies below 600 Hz from going to the squawker change the slope of the woofer response curve. Anything that calms down that midrange horn is a benefit in my book! The "E2" wires the squawker in phase with the woofer; the "E" has the squawker 180 degrees out of phase with the woofer. Time-coherence/step-response is thus improved in the "E2".

davidcl, the paper sticker on the back of your Heresy should indicate if it is a Heresy or a Heresy II. I believe that there is no way your 1983 Heresy's could have the earlier "E" crossover, and I don't know when the Heresy II appeared. The Heresy II has a different tweeter among other things, and my mods don't apply to it. Bob Crites sells a titanium diaphragm upgrade for the tweeter of the Heresy II, I think. If you have Heresy II speakers, for sure check out Mr. Crites' website. My parts-see part numbers in my previous reply to you- (capacitors and stuffing for two speakers) cost around $110. These caps sound cleaner, sweeter and crisper, and they will never fail, unlike the spam cans and especially the 33 muF electrolytic. I really am sure that 1.8 muF tweeter caps sound better than the 2 muF with the K77M.

Happy modding!

This post subsequently edited

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Antone,

My apologies, you are correct the 1.8 raises the crossover. Better for the K77s too!

I do have to say I'm lost as to your stated effects on the midrange. The E2 33uF cap is only in the woofer crossover.

"Time-coherence/step-response is thus improved in the E2"?????

The only reason for the change of polarity in the E2 is that you've changed the order of the woofer crossover and the phase relationship with the midrange also changes.

Chuck

e2.jpg

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Chuck,

I'll take your word for it regarding the squawker/woofer phase relationship[:$]

According to the schematic (thanks for providing it) and my L/C meter, the 33 muF cap is in parallel with the 2 muF squawker cap to yield a sum of 35 muF, measured at the 2 muF cap's (or at the 33 muF cap's) terminals. (Unlike resistance, capacitances add in parallel.) The other 2muF cap (connected to the tweeter) measures 2muF with my meter, so it must not be in parallel with another cap. It is, however, in series with the squawker's 2 muF cap (which itself is in parallel with the 33 muF cap). As you know, capacitors in series don't add; rather the lower (lowest)-valued cap prevails. Since the series caps are a 2 muF and, in effect, a 35 muF, 2 muF is the value at the tweeter cap.

The 33 muF may be located at the woofer output screws, but I believe that it still acts upon the squawker in combination with the 2 muF to form a 35 muF high pass filter for the squawker. I sense that you may know more about 1st- vs. 2nd-order crossovers than I, so thanks for your info.

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my L/C meter, the 33 muF cap is in parallel with the 2 muF squawker cap to yield a sum of 35 muF

sorry, your measurements are based on assumptions that your L/C meter is using AC to measure capacitance. your L/C meter is using DC to measure capacitance (it runs off a battery, correct?). The crossover is an AC circut. The woofer inductor isolates AC signals between the woofer and the squaker. Therefore, the woofers shunt capacitor has no influence on the squakers in line capacitance in a real world application based on AC signals.

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The L/C meter measures C by appying a DC voltage and measuring the time, R/C time constant, it takes the cap to charge. Longer time bigger cap! The coils and autoformer are effectively shorted out for this DC test.Under these contitions the 2 caps are in parallel.

This isn't how it works in a AC environment!

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This isn't how it works in a AC environment!

in a DC environment, DC can pass thru the inductor , so no matter what side of the inductor you are on, your DC capacitance meter can take measurements.

in an AC environment, the inductor isolates the two capacitors. only frequencies below 400hz can pass thru the inductor, however, the squaker circut operates above 400hz....so in effect....you hit a brick wall .

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Chuck and Speakerfritz,

Thanks for the reminder; I think in DC to a fault. No signal above 450 Hz makes it past the 4 mH inductor to the 33 muF cap. So what does the 33 muF cap accomplish for the woofer by bridging its plus and minus? I guess it's a second order with a steeper slope, but how does the 33 muF cap cause that?

Take me to school[*-)]

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Chuck and Speakerfritz,

Thanks for the reminder; I think in DC to a fault. No signal above 450 Hz makes it past the 4 mH inductor to the 33 muF cap. So what does the 33 muF cap accomplish for the woofer by bridging its plus and minus? I guess it's a second order with a steeper slope, but how does the 33 muF cap cause that?

Take me to school[*-)]

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Chuck, Thanks for the graphs[Y] I see the steeper roll-off of the "E2", but I don't know some of the terms of the table. I think I get 'f'', 'z' & 'L' (frequency , impedance, and inductance), but I don't understand 'x', 'p', or 'c'. I see that the response graph is in decades instead of octaves? (In college I was a music major with electrical engineer roommates.)

The bigger inductor starts the roll-off at a lower frequency, but it's the 'order' that dictates the steepness?

Thanks

P.S. the "smiley"[*-)] that I used in my last post was the "confused", not the roll-eyes.

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z = speaker impedance fixed at 8 ohms which isn't correct, but is ok for the example.

Xl = coil impedance at frequency = 2 * pi * f * l

Xc = cap impedance at frequency = 1 / 2 * pi * f *c

zp = parallel impedance of the cap and speaker Xc*z / Xc+z

Vo = zp / (zp + Xl)- simple voltage divider assumes 100% in percentage out.

dB = conversion to dB = 20*log10(Vo)

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Chuck,

Thanks for the definitions. My understanding of the function of the 33 muF electrolytic has been incorrect, but my part recommendations and sonic descriptions remain the same. I have edited some of my earlier posts to reflect the improvements in my understanding. (Thanks to you and others in this forum!)

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The capacitor in parallel has the effect of bleeding some some of the signal off the driver as frequency rises. The combination of the coil in series with the cap in parallel will increase the roll off effect of the filter "system". The two components combined with the reactance/inductance of the driver are all inter related. Change one and you have to change the other to keep the same filter system characteristics. You can tune the filter roll off response by using higher or lower cap values. This is usually termed the 'Q' of the response and comes into play in getting the smoothest blend of the drivers at the crossover frequencly. You also need to factor in the driver acoustic response and its impedance curve.

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DavidF,

Thank you for explaining how a cap straddling the woofer terminals affects bass roll off. This indicates that direct substitution of the caps and coil with better ones of the same values is the more conservative bet. I arrived at the 3.71 mH for the woofer coil by trial and error. (One of the original "4 mH" woofer inductors actually measured 3.8 mH, anyway, so my 3.71 mH spec is basically within the margin of error that Klipsch allowed.) The roll off starts a titch higher, but my specification of a better woofer cap of the same value, 33 muF, keeps the slope of the roll-off similar.

My recommended Dayton 12" woofer (#295-120) has the same 8-Ohm impedance as the Klipsch K-22E, and my Dayton woofer's inductance, 3.07 mH, is within 10% of the K-22E's 2.8 mH. Remember, Klipsch allowed a 5% tolerance in woofer inductors from left speaker to right speaker.

Before my modifications my Heresy's sometimes sounded midrangey, lacking depth, smoothness and high end extension. I voiced the midrange and treble using my STAX electrostatic headphones as the model. For the bass I took a few hints from the acoustics of the Advent speaker (stuffing&sealing the enclosure, choosing a potent, efficient driver with a BIG magnet and response down to 25 Hz).

Once again, DavidF,

Thanks

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  • 2 weeks later...

Having read this whole thread, I can say two things.... First, Antone is having fun and doing cool things with the Heresy box. Second, Although the dimensions remain the same..... it's no longer a Heresy. It's now an Altone-I, etc. The overall characteristics of the speaker have changed; per Antone, for the better.

Let's think outside the box, Antone (great pun!!! LOL!!!)... Given the characteristics described, etc., I would point you to take the same components and experiment with a Tangent-400 ported box design..... LOL!!!

Report back or else!!! [;)]

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Groomlakearea51,

Thanks for your suggestion (and for correcting the spelling of my screen name; I'm a big believer in editing my posts to fix typos and such). My initial goal was to fix issues with the spectral balance of the Heresy I's without losing their character -which is why I chose them 29 years ago. The three features most responsible in my estimation for the Heresy sound are: the midrange horn (squawker), the balancing network with its T2A autoformer, and the enclosure.

My modifications left the squawker section of the crossover, the midrange driver and the lens (horn) unchanged, except for a direct substitution of the squawker spam-can capacitor with a metallized polypropylene cap of the same value. So the midrange of my modded Heresy is basically unaltered- just a titch cleaner and more solid. (In fact none of my crossover mods changed the design of the network; all I did was to directly substitute higher quality, narrower tolerance components (slightly tweaked in value, but still basically within the original components' tolerance margin). What my Heresy's always lacked were: bass deep and loud enough to balance squawker output, and treble response to 20 kHz (hence my modern woofer and titanium tweeter driver).

The simple problem with the bass is really due to the enclosure being too small. Stuffing the box truly and noticeably improves this situation, as well as using a much more efficient (lower loss) woofer inductor. This is a compromise, however. The ideal solution would be to use a larger sealed enclosure. Famed loudspeaker designer, John Dunlavy, stated his belief that the best route to phase-coherent, flat bass response all the way down to 20 Hz is a large, airtight enclosure of correct volume.

Ported designs are a compromise, but perhaps a better one than a too-small sealed enclosure. Ported designs I have heard usually had lumpy, sloppy-sounding bass, but it was louder. My sealed, stuffed Heresy's now have more and deeper (about an octave) bass, but they still need to be placed in the corners-a sign that they are still Klipsch speakers. The way to go from here does seem to be rethinking the enclosure. That's a big step.

Your idea of using my drivers in a totally new enclosure has merit, and I would like to know more about the Tangent 400. Please elaborate:)

Antone

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Antone,

I agree with your premise as to the lack of bass in the Heresy. I just solved it in a different way by adding L/R subs. In my system every thing below 80Hz is directed to the subs.

I've swapped my Heresy IIIs several times for my rebuilt Heresy Is and the IIIs IMO are far better.The IIIs have a totally different crossover than the earlier Is and IIs.It has no autoformer. I'd love to find a schematic for it!

The I and II have a wild impedance swing because of the reflected impedance of the upper horns. There is a schmatic some place on the forum that used an 11 ohm resistor across the autoformer and a change to the input cap to fix this. The next time I open the Is I may try this.

Also, Bob Crites has a cabinet called the CS 1.5 where the box is larger and is bass reflex.

Chuck

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