Please help me understand my Heresy II crossovers a little better�

[elviszappa]

I’m
trying to “wrap my head around” what all the components in a crossover
are doing and how they relate to each other. Looking at the schematic below (thanks to the original poster ... Bob Crites I believe). I have a few questions.
I’m not trying to redesign my crossover just fully understand it.
I understand that in the woofer circuit the coil and cap create a low pass
filter. I read in a post by Antone ..
(http://community.klipsch.com/forums/p/143885/1471593.aspx#1471593) .. that
he lowered the DCR and the mH value of the coil to increase the output
of the woofer. Does this make sense … would it increase the output?
Would lowering or raising the value of the woofer capacitor change the
crossover point?

In the mid-range circuit I’m not clear on the
autotransformer. I believe it is to balance the mid-range horn with the
woofer and tweeter. Is that correct? Looking at the new replacement ones
that Bob Crites is selling I wonder what would be the effect of
changing the tap to say -12dB or -09dB? Would raise or lower the output
of the mid horn? Also why could it not be replaced with a resistor to
get -10dB cut … is there some purpose it serves that I’m missing?

Does anybody know the DCR value of the stock 2.5mH and the .16mH coil/inductors?

And lastly on a separate note, what combination of coil and cap would create a 3000 Hz high pass filter.

Thanks for any info you can give me. EZ

[BEC]

I’m
trying to “wrap my head around” what all the components in a crossover
are doing and how they relate to each other. Looking at the schematic below (thanks to the original poster ... Bob Crites I believe). I have a few questions.
I’m not trying to redesign my crossover just fully understand it.
I understand that in the woofer circuit the coil and cap create a low pass
filter. I read in a post by Antone ..
(http://community.klipsch.com/forums/p/143885/1471593.aspx#1471593) .. that
he lowered the DCR and the mH value of the coil to increase the output
of the woofer. Does this make sense … would it increase the output?
Would lowering or raising the value of the woofer capacitor change the
crossover point?

In the mid-range circuit I’m not clear on the
autotransformer. I believe it is to balance the mid-range horn with the
woofer and tweeter. Is that correct? Looking at the new replacement ones
that Bob Crites is selling I wonder what would be the effect of
changing the tap to say -12dB or -09dB? Would raise or lower the output
of the mid horn? Also why could it not be replaced with a resistor to
get -10dB cut … is there some purpose it serves that I’m missing?

Does anybody know the DCR value of the stock 2.5mH and the .16mH coil/inductors?

And lastly on a separate note, what combination of coil and cap would create a 3000 Hz high pass filter.

Thanks for any info you can give me. EZ

We can use this one as a general example of how a crossover got to be like it is.

First we have the woofer and other components in the cabinet and we send a signal to just the woofer measuring the response of the woofer raw, in other words, with no crossover. We see in this case good relatively linear output to somewhere above 700hz. So, that output becomes the basis for our network. The woofer filter rolls off the woofer output at 700hz by 12db per octave.

So, now we measure the raw response of the squawker. We will see it is linear from somewhere below 700hz to about 6khz. We also see that it's output is 10db higher for the same voltage signal as the woofer output. So, we use an autotransformer to decrease the output by 10db to match the output of the woofer. We also choose an appropriate capacitor (the 1.5uF) to bring in the squawker at 700hz balancing it with the woofer output frequency we limited to 700hz earlier.

Now we test just the tweeter raw. We see that it is linear from around 4khz to around 18khz. Output level is about right allready to match the output of the woofer. So we just need to match it up in frequency. In this case we use a filter (2 1.5uF caps and a 160uH inductor) to bring in the tweeter at 6khz. We bring this on pretty steeply (18db per octave) since the tweeter raw would be at full output earlier than the point we want it.

So now if we put in a full range signal to the complete speaker through the crossover, we should get a pretty linear output all the way up. Now this is much simplified compared to how this actually happens. It is unlikely the final design is the first try like I made this sound. At least for me, takes several tries. Also, I left out a lot of stuff about impedance and phase and where the drivers actually want to match up. So, don't get the idea that building speakers that work good is that simple.

On the autotransformer question, yes, you could do that with resistors. In that case you would take a bunch of power from the amp and dissipate most of it as heat in the resistors. The autotransformer does this without ever drawing the power from the amp in the first place.

Bob Crites

[mustang guy]

We can use this one as a general example of how a crossover got to be like it is.

First we have the woofer and other components in the cabinet and we send a signal to just the woofer measuring the response of the woofer raw, in other words, with no crossover. We see in this case good relatively linear output to somewhere above 700hz. So, that output becomes the basis for our network. The woofer filter rolls off the woofer output at 700hz by 12db per octave.

So, now we measure the raw response of the squawker. We will see it is linear from somewhere below 700hz to about 6khz. We also see that it's output is 10db higher for the same voltage signal as the woofer output. So, we use an autotransformer to decrease the output by 10db to match the output of the woofer. We also choose an appropriate capacitor (the 1.5uF) to bring in the squawker at 700hz balancing it with the woofer output frequency we limited to 700hz earlier.

Now we test just the tweeter raw. We see that it is linear from around 4khz to around 18khz. Output level is about right allready to match the output of the woofer. So we just need to match it up in frequency. In this case we use a filter (2 1.5uF caps and a 160uH inductor) to bring in the tweeter at 6khz. We bring this on pretty steeply (18db per octave) since the tweeter raw would be at full output earlier than the point we want it.

So now if we put in a full range signal to the complete speaker through the crossover, we should get a pretty linear output all the way up. Now this is much simplified compared to how this actually happens. It is unlikely the final design is the first try like I made this sound. At least for me, takes several tries. Also, I left out a lot of stuff about impedance and phase and where the drivers actually want to match up. So, don't get the idea that building speakers that work good is that simple.

On the autotransformer question, yes, you could do that with resistors. In that case you would take a bunch of power from the amp and dissipate most of it as heat in the resistors. The autotransformer does this without ever drawing the power from the amp in the first place.

Bob Crites

Thank you Bob for bringing clarity to the fundamentals of design of a crossover network. Very well said!

[Deang]

"...that he lowered the DCR and the mH value of the coil to increase the output of the woofer. Does this make sense … "

http://www.audioasylum.com/audio/tweaks/messages/82448.html

In general, messing with low pass coils is a bad idea. You can raise woofer output by simply moving the speaker closer to walls/corners.

"Would lowering or raising the value of the woofer capacitor change the crossover point?"

The cap reduces the amount of high frequency content going to the woofer and so makes the slope steeper. The cap and coil together are of part of the crossover point to the midrange driver. Someone will be sure to correct me if I'm wrong, but I don't think it will effect the actual crossover point, just the slope. Leave it alone.

"In the mid-range circuit I’m not clear on the autotransformer. I believe it is to balance the mid-range horn with the woofer and tweeter. Is that correct? Looking at the new replacement ones that Bob Crites is selling I wonder what would be the effect of changing the tap to say -12dB or -09dB? Would raise or lower the output of the mid horn? Also why could it not be replaced with a resistor to get -10dB cut … is there some purpose it serves that I’m missing?"

You can change the taps to manipulate the output of the drivers, but not without changing the capacitor value going to the input tap (tap 5). The reflected impedance doubles everytime you move down a tap. So, to drop the midrange 3db, you would move to tap 2 on the autoformer and change the primary cap from a 2uF to a 1uF. Since impedance doubles, you have to cut the capacitance value in half to keep the crossover point the same.

And lastly on a separate note, what combination of coil and cap would create a 3000 Hz high pass filter.

You need to the know the impedance of the drivers at the crossover point. Presuming they are exactly 8 ohms, the values would be 4.7uF and .6mH.

[elviszappa]

Thanks Bob and Dean for your replies. You have answered and clarified all my questions.
Does either of you know the DCR value of the stock 2.5mH and the .16mH
coil/inductors? I'm planing on a complete rebuild of my Heresy II
crossovers after a previous recap only rebuild. I'm thinking of using
air core coils and I would like to match the DCR as close to the stock
ones as I can. Right now I'm looking a Mundorf caps, Supreme or
Sliver and Oil. Also a new autotransformer from Bob and air core coils
maybe from Jantzen. If I make it "pretty" enough I'm toying with the
idea of leaving them outside the cabinets ! EZ

[Axz Hout]

t

[BEC]

That original 2.5mH ferrite inductor is about 0.5 ohms DCR.

EDIT: Humm, we got considerably different numbers.

Bob Crites

[Deang]

Chris' coil has less copper.

Bob, do you still have UT wind those 2.5's for you, or are you strictly using those steel laminates from Parts Express?

[BEC]

I have UT make most of my inductors. I buy some from Erse if they happen to be in the mood to make them. More and more of them all the time I am having UT make.

[Deang]

...I'm planing on a complete rebuild of my Heresy II crossovers after a previous recap only rebuild. I'm thinking of using air core coils and I would like to match the DCR as close to the stock ones as I can. Right now I'm looking a Mundorf caps, Supreme or Sliver and Oil. Also a new autotransformer from Bob and air core coils maybe from Jantzen. If I make it "pretty" enough I'm toying with the idea of leaving them outside the cabinets ! EZ

Use the silver and oils if you can afford them. Also check out the OIMP V-cap, which are excellent sounding capacitors and I think they might actually cost a little less. If you go to an air core, use the 2.5mH from Erse http://www.parts-express.com/pe/showdetl.cfm?partnumber=266-380 but to be honest, there is no problem with using an iron core unless you listen at ear bleeding levels. I don't know what to think about that cap in parallel. I'm in the middle of reading some stuff that's making me reconsider my original position -- which was to just use an electrolytic. The Jantzen's are nice coils -- highly recommended.

Thoughts on the following?

'"Critical components" - series components versus parallel.

Oh I've heard it so many times. "In this crossover network use premium caps in series with the driver, but the coil is ONLY (!) parallel so it is unimportant. And this parallel cap can be WIMA el cheapo because it is not in the path." PUHLEEZE! People think of the electricity as a row of ants marching through a path. The series component must be good because they walk on it like over a bridge. Parallel components are like road signs on the side of the path, They are there, but don't affect the "marching process". NOT TRUE. Electricity is an electromagnetic energy propagating through the network, NOT marching ants. The parallel components distort the signal THE SAME WAY AND THE SAME AMOUNT as parallel. Imagine a sheet of paper. A4 on this side of Atlantic. Now tear it in half. Which torn part has more distorted edge? See? Both equally. Because what is removed takes away from the whole some amount of distortion, or what stays - leaves some distortion. No difference. Mathematically speaking there is no difference between the effect on the mathematical equation that has the application of say z=jwc or z=1/jwL. For example, if you open a series cap and if you short the parallel coil in second order filter the result is THE SAME. No signal. Still don't believe me? OK. The coil in parallel application of second order network is not really parallel to the signal. It is in series! Yes. The current from amp flows through the speaker wire, through the series cap, and through the parallel coil to earth. This current produces over the coil's impedance some voltage proportional to the impedance (reactance) of coil with ALL ITS DISTORTION COMPONENTS and this voltage is fed to the driver. Does it still look unimportant?"'

[BEC]

Quote above assumes a distortion component present in one cap and not in another cap. Proof please.

[elviszappa]

You may want to take a look at Humble Homemade HiFi capacitor test page

... http://www.humblehomemadehifi.com/Cap.html ... if you have not seen

it already. I've talked, via email, with the owner Tony Gee and he has

been very helpful with information and recommendations tailored to what I'm trying to achieve with the upgrade. I had asked him

about using different caps in parallel and he said he's had "some" good

results but they must be close to equal in value to make them "blend"

together.

I realize his

tests are very subjective but like that he is a speaker builder and he also

builds his own crossovers. If you read his intro on the capacitor test

page you'll see is test methodology. If nothing else it's another source for

info my various brands and types. EZ

[Axz Hout]

y

[Deang]

You may want to take a look at Humble Homemade HiFi capacitor test page ... http://www.humblehomemadehifi.com/Cap.html ... if you have not seen it already. I've talked, via email, with the owner Tony Gee and he has been very helpful with information and recommendations tailored to what I'm trying to achieve with the upgrade. I had asked him about using different caps in parallel and he said he's had "some" good results but they must be close to equal in value to make them "blend" together. I realize his tests are very subjective but like that he is a speaker builder and he also builds his own crossovers. If you read his intro on the capacitor test page you'll see is test methodology. If nothing else it's another source for info my various brands and types. EZ

He is is at the extreme end of the spectrum. I can't claim to hear all of the things he claims to hear. The differences I hear are general in nature, and in all of my years of being exposed to this stuff, I have never heard someone suggest that capacitors in parallel '"must be close to equal in value to make them "blend" together"'. There are people who say capacitors need 400 hours or more of break in, I'm not in agreement with that either. He used to do his speaker listening tests with Magnepans, he lives in a very different world than those who use horns and compression drivers.

[Deang]

Quote above assumes a distortion component present in one cap and not in another cap. Proof please.

We discussed all of this on the phone, so it seems silly to type it all out here, but people are following the thread so I guess we need to fill in the gaps. I also know you're a lousy typist and I really don't want to put you through all of this, so I'm just goint to go ahead and tell everyone what you said.

I told Bob to Google "capacitor distortion" and that he would find plenty to read about. Bob said that if there is distortion, it is very low, and would be covered up by components in the system generating distortion many magnitudes higher - like the diaphragms on the drivers for example. I decided Bob was right, but still think distortion, even the low level variety, isn't good. At this point, I'm going to move comments to the other thread where they belong.

[elviszappa]

"He is is at the extreme end of the spectrum" .... "he lives in a
very different world than those who use horns and compression drivers."

I
sure your right on both points, though looking at some of his speaker
designs, other than some of his elaborate baffling and his crossovers,
they seem fairly straight forward. I sure his prices are way above
anything I could afford though. I did send him a copy of the Heresy II
crossover circuit diagram and he was more than helpful recommending cap
replacement ideas with no "buy from me" motive behind them. I though
that
was very nice of him.

Like I said earlier, if nothing else it's
another source of info on various brands and types of caps. Other than
me
going out and buying a pile of cap's and trying to compare them myself
(which is beyond what I have the ability or setup to do), it gives me the
opinion of someone who seems to be very knowledgeable and passionate
about speaker components. It's another view I can try to learn from.
Like I have here and other forums from the likes of you, Bob C, Al K and
many many
others.
My whole goal is to get every last ounce of quality sound out
of my Hersey's that I can ... short of replacing them (that a whole other
story!). Also unlike some Klipsch fans I have no qualms about altering
the "original PWK sound" if it sounds better to me in my setup. If the "original PWK sound" is so sacred why did they come out with the Heresy II and III?
Even Klipsch is trying to improve the sound ... as well they should. Blasphmy I know, but to each his own. EZ

[elviszappa]

"I have never heard someone suggest that capacitors in parallel '"must
be close to equal in value to make them "blend" together".

This
opinion came as a response to my question about paralleling different
brands of capacitor to get a sort of "best qualities of both" (my term)
combination.

To quote his reply "Pairing different types to create a certain blend can work quite well
but can be a bit tricky to make them "melt" into one sound. Some mix
very well, like Clarity Cap SA with Mundorf Surpeme or Intertechnik
TriReference with Mundorf Silver Oil. Best seems to be when the values
are about 50/50."

I don't presume to speak for him but I don't
think he was in any way trying to imply some sort of hard and fast rule.
It's all just food for thought. EZ

[Arkytype]

[DavidF]

I would offer some caution about using expensive components

in a Heresy II. Some in the forum will argue otherwise and might offer advice more in line with your expectations. What works for you is always the key.

The drivers of the Heresy are good quality but hardly in the

higher end of the engineering/price spectrum. In any event they sum together to

work beyond what could be expected of them.

Personally I would hesitate at spending more for the crossover

than all of the drivers put together.

More of a cost/benefit consideration rather than a penny-pincher’s

lament.

I have the Heresy II and have used a few different component

combinations. The only noticeable difference was using a better

quality cap in the mid leg of the xover. The effect was to allow for more

detail in the mix. Not so much that I could guarantee hearing the difference on

any recording, or necessarily at any time. What I am trying to say is that any

improvement for me was fleeting. I went

with Clarity Caps all round since the component values are small for all legs.

I can’t comment on different coils. I use a larger gauge

wire with laminate core. I did not notice any difference but I don’t push the

Heresy’s that hard. The sound loses coherence and dynamics when the sound

levels get high.

[moray james]

I don't think you want to increase the output of the woofer at crossover or its upward range (crossover point) I do think that the speaker can stand to have more bass output though but that is a different issue. I think that a better way to address the bass issue is with cabinet brace work and internal damping and I also think that some acoustical filtering of the woofer also helps a lot as well.

just curiious what your intended goal is because it does not seen like the H2 is what you are after? If you would like my suggestion, forget the H2 and step up to an H3. While I am a fan of the autotransformer for the mid and hi I have a pair of Heresy which are almost H2's and a pair of H3 . Along with owning a good numberr of otherer speakers like Forte, Forte ll, Quartet,KLF20 and CF3 all but the CF3 I have installed Titanium diaphragms into (cf3 soon enough too) and I have to say the H3 sound good. All this to say there are a number of way to get the job done but if I had to choose who I would follow today it would be Roy Delgado. I imagine Roy knew PWK very well and Paul was one clever man. One of the members here suggested running a separate auto transformer for both tweeter and mid horn. So what is it you are considering doing? Best regards Moray James.