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radiogram

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  1. @mboxlerI think I understand what you are driving at. Perhaps I did not communicate my expectations clearly. A properly implemented LPAD will give desired attenuation and yet make the network see the same load as before and thus without altering the frequency response that was there before the LAPD was inserted. A simple series resistor will not maintain the same freq response and so attenuation at different frequencies will be different. So I am not expecting same attenuation at all frequencies. What I am saying is the the insertion of 3 ohm resistor makes no real difference in output across tweeter (as compared to without 3 ohm) in the tweeter's passband which is about 5.5K and up. Except for -1.9dB drop at 20K from 6K to 16K the final attenuation is not even -1 dB let alone -3 dB. And the intent here was to lower the Tweeter output by 3 dB compared to the woofer. So with the amplifier giving the same voltage to the network, the insertion of 3 ohm has not shown any meaningful measured difference in the tweeter's most of the passband.
  2. @mboxlerThe attenuation we are looking at is after vs before inserting the resistor because that is the end result we want as Without changing the volume of my amplifier I want Tweeter attenuated. Yes if you just compare voltage across tweeter vs 3 ohm sure we get -2.27dB drop and the math is right. But this not the real attenuation we are looking for. . So, the real attenuation is 20 * LOG((Voltage Across Tweeter w/o 3 ohm series) / (Voltage across tweeter with 3 ohm series) ). So for say 4K Hz it is 20 * LOG(.094/.1020) = -0.709 dB Only.
  3. @mboxler- There are no other series resistors other than the 3 ohm I added. if we assume an average impredance of 8 ohm for the tweeter then the total load impedance has increased from 8 to 11 ohms. Then the volatge across the tweeter should be 72% (8/11) translates to power drop of about -2.7 dB (20 * LOG(8/11)). But my measured date shows at no frequency it is not even -2dB. In fact at 8K and 10K it pretty much -0.3dB only. from My experiments I figure the mid driver K53 approximation of 16 Ohms hold good, but for the tweeter 8 ohm does not hold good. In 6K to 10K 10 ohm holds good. Beyond 12K Tweeter impedance increases as we up the frequency. Anyway I just got Hand held OWON oscilloscope and will re do my measurements as my Fluke multimeter readings above 1K are suspect and post my findings again. Also note that I just realised I replaced my Titatinum tweeter diaphragms with Bob Crite's diaphragms and they are no longer original Klipsch diaphragms.
  4. However, my LPAD for Mid section seems to measure well. Assuming 16 Ohms for K53Ti, for 3dB I used 4.7 ohm Series and 40 Ohm Parallel and here are measurements, Looks good enough as below measured:
  5. @mustang_flhtand others: In my attempt to modify CW III Crossover to H III with LPAD attenuation to compensate 3db difference with CW III, I first tried to see what Klipsch did with Tweeter circuit by inserting a 3 ohm series resistor before Tweeter. I inserted 3 Ohm Series Resistor and I am surprised that measurements of voltages before and after 3 Ohm Series show not much difference at all. There is not even 1 dB attenuation in the tweeter pass band, let alone 3 dB. Here are my measurements. Note -Please do not look at the Absolute voltage values, as my meter cannot measure full voltage beyond 1 KHz. Above 1 K its readings get tilted down as we go up in freq. But what we are interested is only the Delta not absolute value. What is wrong here? Also notice the Voltage across (3 Ohm + Tweeter) increased as opposed to Voltage across just Tweeter. Do not understand why Voltage is not same. What is wrong here?
  6. @mustang_flhtI recognize Audyn and Jantzen. What make are the inductors, blue caps and resistor (Mills?)
  7. @mustang_flhtMan those are some nice parts! Is this a custom modified network (not stock CW III)? Because I see only two inductors instead of 3 and only 1 resistor instead of 2 and I also see more caps.
  8. @mustang_flht Thanks for the cooling tip. I am India and have no access to 25 Watt resistors of decent quality easily. For now I am going to experiment with 10 Watt resistors and once I am satisfied I will probably get them from mouser/madisound etc when my sister comes here next month. BTW, I am now using Bi-Amping to make up for sensitivity difference between bass and mid-highs with the Integrated Amp driving the bass is boosted up. In this I actually find that I prefer the mid-highs 4db lower instead of 3db. I am also curious that a much less sensitive speaker (only 85 db) like JBL A130 I have, uses 1only 10 watt resistor when I would expect much more power going into this than the Heresy. Thanks
  9. @CrankysoldermeisterYes as far as the mid and High Section the Crossover is same except for Resistor values used for padding. Most of my listening is low to medium volumes. Thanks
  10. Heresy III / CW III : 25 Watts Resistor really needed?? Having recently figured out the resistor values in mid and tweeter section for H III Xover, now I am going to convert my CW III Xover to H III Xover by substituting the resistors. These resistors are all spec'ed at 25 Watts. Where I live I can only get 10 Watt Daytons. So only option is to buy two 10 watts resistors of half value and use them in series (to get up to 20 watts) which I rather not do as physical layout will not be a simple swap of resistors. Do I really need 25 Watts resistors for mid and highs? Can I get away with 10 Watts? Thanks
  11. Having recently figured out the resistor values in mid and tweeter section for H III Xover, now I am going to convert my CW III Xover to H III Xover by substituting the resistors. These resistors are all spec'ed at 25 Watts. Where I live I can only get 10 Watt Daytons. So only option is to buy two 10 watts resistors of half value and use them in series (to get up to 20 watts) which I rather not do as physical layout will not be a simple swap of resistors. Do I really need 25 Watts resistors for mid and highs? Can I get away with 10 Watts? Thanks
  12. @mustang_flht, @Donkeyshins, @CANT, @ccwarrior I have figured out the HIII mid and high section network. We already know from @CANTthere is a 20 Ohm resistor in HIII in place of the 50 Ohm resistor in CWIII. This is the mid section parallel resistor. With 20 ohm parallel, if I reverse calculate what should be the Series Resistance for 3 db lower, it comes to 51 ohms. So for HIII schematic, take the CWIII network and for mid section - simply swap out the 50 Ohm resistor with 20 ohm and swap out the 30 ohm series resistor with 50 ohms, and for high section just add the inline 3 ohm series resistor. It is possible bass section may be same because both the K33 and K28 are 4 ohm drivers. But I could be wrong here.
  13. @mustang_flhtbut won't that change the freq response? I believed That between CIII and HIII mid and High section the only difference will be around 3dB more attenuation compared with the CIII as HIII is 3db lower than CIII. But if you have HIII Tweeter circuit with just a 3 Ohm Series Resistor then the freq response is not going the the same as CIII unless you do a proper L-Pad. I am confused.
  14. @mustang_flht @001 The mid and tweeter sections between CIII and H111 should be identical except for Resistors' values. We know that the 50 ohm Parallel Resistor in mid section in CIII is 20 Ohm in HIII. Makes sense it is lower since HII needs more series attention so parallel value is Lower than the CIII. The Tweeter section, based on a past CANT's post, there is a series 3 ohm resistor which takes up the empty space marked R4 in the CIII network. But this does not make sense since we need L-Pad not just a series Resistor. Surprised HII Xover has not been really addressed in this forum in spite of it being out of production for a few years now. Do you think we could get Klipsch themselves to reveal the schematic in this forum? Cheers
  15. @mustang_flhtDo you know if HIII schematics was posted by anyone? if so please let me know. Thanks
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