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Klipsch Balancing Network Mysteries


ishwash

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Looking at a Type B balancing network's autotransformer, I see the input is occupying Taps 0 and 5. The squawker uses tap 3 and the tweeter uses tap 4. Somebody, somewhere, said tap 1 is the  -12db tap. I  presume then that 2 is -9db, 3 is -6db tap and 4 is -3db?

 

To reduce the squawker volume by 3db, I understand I could change its tap to 2, and I gathered from reading somewhere that the change might necessitate a capacitance change for the squawker. How do I determine what the new capacitor should be?

 

Conversely, to increase the squawker volume I could change its tap to 4 (and I read somewhere else that its okay to have both the tweeter and squawker attached to the same tap). Need a different capacitance for the squawker? And again, how do I determine the squawker's new capacitance requirement?

 

I would imagine that one of the above would not require a capacitance change.

 

Thanks for any response I get on this, hopefully I am not so far below zero that I am hopeless case....

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You have options... 

To attenuate midrange 3 db drop tap to squawker from 3 to tap 2 and use 1.5 uF instead of 3 uF cap OR add 15ohm resistor parallel on mid output.  You can avoid the cap change by installing a 15ohm resistor across the squawker connections.  I think I used a Mills non-inductive.  The resistor option makes it easy to test and put back the way it was if you prefer.  

 

image.thumb.png.a01cb727d46b2bac55da95b2523c8dbd.png

 

 

If you have a B network you might like to look at converting to a B2:

About the trickiest part was moving the grounding wire as I remember.

image.png.f10c67f5b43bcc97f5143e0dc6faf2b0.png

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From Klipsch re: B2

 

CROSSOVER NETWORK CHANGED:   CORNWALL

Vol. 20, No. 1

June 1, 1981

 

NEW DEVELOPMENT

The product-evaulation program at KLIPSCH and Associates constitutes the lion's share of our Research and Development effort. We are now gratified to add another entry to the long list of performance improvements made in our product line over the years. Advances in the state-of-the-art of sound reproduction frequently result from innovation of new techniques of acoustic measurement, the aim being to utilize quantitative tests which closely corroborate the psychological sensations of the listener. Thus new measurement techniques or bolstered power and convenience of data-conversion bring excitement to the work of design, but always with the sobering constraint that new test results carry import only to the degree to which they have psychological significance. That is, the test format must be such that the genuinely most significant acoustic parameters receive the greatest emphasis during

design. The latest in a long series of "technical papers" from KLIPSCH Engineering explains the operation of our unique "Anechoic Chamber With Optional Boundaries" (AES Preprint 1979) which facilitates deeper scrutiny of loudspeaker response characteristics.

 

The KLIPSCH CORNWALL has taken yet another step in its evolution toward optimum performance.  A complete re-design of the crossover network has made possible a significant improvement which we now happily share with the audio public. Briefly, the new design entails the following:

 

1) Constriction of the electrical signals received by each driver to the spectral band over which the driver displays optimum characteristics is a salient feature of the design.

 

A)       Boosted woofer output is obtained in the 400 Hz to 600 Hz region.  Combined with a more rapid transition to an attenuating characteristic at frequencies above cut-off.

 

B      Substantially decreased low-frequency  energy is applied to the midrange driver.  Though tremendous improvements are not possible in this regard, intermodulation distortion is somewhat reduced and the possibility of squawker failure is made even more remote.

 

C)       Dramatic improvement in the stop-band attenuation is provided by the highpass filter associated with the K-77MTweeter. Overall, this means that more energy can be derived from the tweeter above 6 kHz because of reduced current-flow into the tweeter in the mid-band.

 

2) Studies of the cross-correlation of woofer and squawker output waveforms have precipitated a substantial increase in coherence near the crossover frequency.

 

A)       The attenuation characteristics of the woofer (low-pass) and squawker (high-pass) filters are associated with a particular set of phase characteristics; the two are mutually dependent and cannot in general be manipulated individually. The roll-off rate of the woofer filter and the spectral location of the cut-off point of the squawker filter govern the relative phase relationship of their outputs in the crossover band. Only a special set of circumstances will allow optimization of filter phase characteristics without an associated deleterious effect on the amplitude attributes of the filters' transfer functions.

 

B       Driver polarity does not affect the amplitude response of the driver in question, but does in fact greatly affect the steady-state response of the system considered as a whole. In this case, the mechanical location of the sources, the phase characteristics of the electrical filters, and the relative polarity of the drivers are manipulated in a harmonious manner to render the crossover-band response smooth and non-anomalous.

 

Designated the Type B-2 Crossover, this new network is aimed at genuine improvements to the overall characteristics of the CORNWALL Loudspeaker System. The effective date of this change is approximately June I, 1981. We plan to make the transition in smooth manner, hence the early notice.  As always, we will maintain stock of Type Networks and adequate repair facilities for CORNWALL  owners.  Since in general no change in drivers.or cabinet is associated with the network, an update from the Type B to the Type B-2 will be a relatively simple matter.   Owners of older CORNWALLS are  encouraged to incorporate up-to-date drive components (K-33E, K-55V with nested phasin plug, and K-77M) to maximize the benefits derived from use of the B-2 Crossover. An update kit (Type B to Type B-2) will soon be made available through the KLIPSCH dealer network.

 

DAN BYNUM

ENGINEER

 

DB:rh

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Inserting a resistor is an excellent way to test your new  tap settings, but I would not make it permanent.  The resistor robs power from the squawker. 

 

This simple calculator will help you resize the squawker cap.  Use 66 ohms and 600 Hz for the Stock B values and adjust the resistance according to the chart below.  

http://ccs.exl.info/installation/crossovers-installation-tweaking/crossover-calculators/#first

 

This schematic gives T2A details.

TypeE.jpg

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Ok, I see all the stuff. I thought I was a nerd, but maybe I am only 3/8 nerd...that is supposed to be a joke.

 

Isn't the function of the two capacitors in these balancing networks to prevent clipping of their respective drivers? If so doesn't that make the value of each capacitor sort of a "subjective" thing and wouldn't it depend a great deal on how loud you were playing your speakers. I mean if it is a public address speaker shouldn't the capacitors be quite large?

 

To provide the ability to check out which tap you wish to use for your tweeter and mid for just normal music playing, couldn't the capacitor value be whatever is prudent to use at tap zero or maybe tap 5 since that value of capacitance would also protect you for quieter taps of the autotransformer?

 

You can go ahead and make fun of my simplistic approach, I won't care, and you can tell me, "look dummy, that ain't the freakin function of the caps"....haha...

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10 hours ago, ishwash said:

Ok, I see all the stuff. I thought I was a nerd, but maybe I am only 3/8 nerd...that is supposed to be a joke.

 

Isn't the function of the two capacitors in these balancing networks to prevent clipping of their respective drivers? If so doesn't that make the value of each capacitor sort of a "subjective" thing and wouldn't it depend a great deal on how loud you were playing your speakers. I mean if it is a public address speaker shouldn't the capacitors be quite large?

 

To provide the ability to check out which tap you wish to use for your tweeter and mid for just normal music playing, couldn't the capacitor value be whatever is prudent to use at tap zero or maybe tap 5 since that value of capacitance would also protect you for quieter taps of the autotransformer?

 

You can go ahead and make fun of my simplistic approach, I won't care, and you can tell me, "look dummy, that ain't the freakin function of the caps"....haha...

1/4 nerd.  These are crossovers, (and balancing).  The capacitors, coils, and autoformer do specific tasks.  Look up "capacitive reactance" and "inductive reactance".

 

The specific values of the components "roll out" and "roll in" the drivers at particular frequencies.  This allows the driver to ONLY work in its optimum frequency range to avoid distortion and/or possible destruction from frequencies that it can not deal well with.

 

Take a look at the picture here:

https://www.google.com/search?q=crossover+network&tbm=isch&tbo=u&source=univ&sa=X&ved=0ahUKEwjX9cqXl4DbAhUEH6wKHRBlDVkQsAQIjAI&biw=1920&bih=987#imgrc=YjfFBGX42PsbMM:

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Thanks, out of my league.

 

I'll see Mr. Crites next week and maybe he can help me decide how to do what I want to do. Still trying to improve my old set of non-Klipsch speakers by using his CT120's and a couple of his fancy mid drivers and a pair of 15" woofers using a Klipsch crossover like the Type B. A sorta Cornwallish mod, I guess. Mids are too loud and tweeter may be as well. I thought I could just start backing down the tap points using my old ears to make the choice of which tap point to use but guess it's harder to do than that because of needing the right capacitor when I change tap points?

 

Thanks for the responses, though, and I'll settle for 1/4 nerd...chuckle...

 

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18 hours ago, Deang said:

What mid-horn are you using?

A-55G driver on a Crites C-600 horn.

 

I am trying to find out if I can just arbitrarily drop down one or two autotransformer taps in loudness (Type B crossover) for the mid-horn to see if it more nearly matches what my ears want to hear without regard to changing the capacitance. Then if it's close to what I want it to be, to change to right capacitance, if necessary, at that time. May want to do the same with the tweeter because its a bit loud too.

 

Course I will need to know HOW to determine what the capacitance should be if a change is required, and if it can be done without having professional sound measuring instruments. Maybe HOW is answered in other posts above, but the answer doesn't stand out to me.

 

It still would seem to me that if you had the proper capacitance for the loudest tap point, that that value would work for quieter tap points, for the simple reason that with capacitors, you need enough, but up to a point, more than enough works just as well.

 

Thanks.

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When I was dialing in my Pro style CornScala's (custom ki-362's) I just bought an assortment of capacitors from partsexpress proper values for a few tap settings which I ended up not really needing. Output level matching of the drivers was what ending up being the deciding factor then I just installed the appropriate cap for the tap setting.

 

BTW I'm using the same tweeter CT-120 and mid driver A55-g but on a k-500 CF-4 horn, that top end is just flat incredible to my ears. I'm not sure what woofers you're using or style of cabinets but you may want to think about getting a pair with high sensitivity rating similar to what is used in the Cornwall or Chorus if you want to keep things simple, its really kind of a shame to have to dial back the horns too far as it seem to me there is a loss of fidelity the further you dial them back but that is just my impressions.

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Using this calculator

 

http://www.pronine.ca/capimp.htm

 

Change Capacitance to uF and Frequency to Hz.

 

A first order rolloff (-3 db) occurs when the impedance of the capacitor equals to impedance of the series load.  This occurs at a specific frequency.

 

The tweeter capacitor ALWAYS has a 8 ohm load (the K-77).  Using the calculator, plug in 2 uF and 8 ohms.  When you click Calculate, the Frequency will show 9947.1875 Hz.

That's the crossover frequency to the tweeter.   Moving the tweeter tap will not change this, because the cap is after the autoformer.

 

The K-55 cap (4 uF) is before the autoformer.  Since it is using input 0-5 and output 0-3, the impedance of the K-55 appears 4 times bigger.  

Assuming the impedance of the K-55 is 15 ohms, the load on the 4 uF capacitor will be 60 ohms.  Plug those numbers into the calculator, and you will get a frequency of around 663 Hz.  If you change the output tap to 0-2, then the load is 8 times bigger, or 120 ohms.  If you want to keep the same 663 Hz crossover frequency, plug in 120 Ohm, 663 Hz Frequency, and the calculator will determine that a 2 uF capacitor is required.

 

Hope that helps!

 

Mike

 

 

 

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Basically the rule of thumb I have read and come to understand is you either double the capacitor value or cut it in half depending on which way you move up or down in output which seems to correspond with the above post. Just comparing the Heresy Type "E" network to the Cornwall type "B' and the Pro Heresy HIP type "HIE" networks gives you a look at the tap settings versus capacitors used; 2uf, 4uf and 8uf respectively.

 

Now when you change frequency to 400hz that changes the values a little as well, I believe the Type "AA" uses a 13uf cap and Mr Crites has recommended 7uf in the original CornScala. Looking at all the info and a couple charts I came up with a 6uf cap for my k-500 with a Type "B" tap setting and it worked out perfect to my ears. 

 

 

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Thanks very much for this info, guys! Something I sort-of understand.

 

Just prepping to make another stab at using my Speakerlab 7's cabinets. Got a pair of parts express Eminence 15" Delta Pro woofers, which I am thinking may be 3 or 4 db louder than the old double woofer arrangement of the 7's and may be about right working with the Crites mids and tweeters. I would have thrown it all away and just bought a pair of Crites Cornscalas, but I love the cabinets, just will have to cut a new motor board. And, oops, I guess I need to admit that I ordered a pair of Cornscalas too...chuckle...I hate throwing away something that has carried me all these years, even tho SL did a lot of copying of Klipsch technology (as did many others); I want to give them new life, and pass them on to our kids to last another 50 years or so.

 

Doubling or halving is a great hint for doing the testing, and the other recs are very helpful too. I wasn't looking forward to bothering Bob Crites about my little problems, although I am sure he would have been very willing to help, but I am sure he gets tired of those kinds of questions being thrown at him.

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Yep, according to Bob Crites: Using a Type B crossover, if I wish to attenuate the mid driver one tap point, I drop capacitance from 4 to 2 microFarads. If I want to drop the tweeter one tap point, the capacitance can be kept the same. All depends on output of my woofer.

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  • 1 month later...

Got a good sound balance using the Crites A55G mid at tap 1 on the T2A (started with Type B crossover) and tap 2 for the Crites CT120 tweeter. Changed capacitor to 1.0 microfarad. Woofer is Eminence Delta Pro 15A. All this is in my old Speakerlab boxes. More a Cornwall now, only the box is Speakerlab. Sounds great, better than it ever did. 

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