Erik Mandaville Posted August 15, 2007 Share Posted August 15, 2007 This is related to a post below re: impedance variations related to voice coil inductance of the horn-loaded K-33 woofer. Athough some effort toward impedance equalization may have been made in recent years (something I don't know), I have been searching for an impedance curve for the above woofer. I've gotten a rough estimate of the upper limit of it's response by using: Fh = expected high frequency limit; Re = voice coil DC resistance; and Le = voice coil inductance in the following formula: Fh = Re/(2piLe), which, itself, is just a point from which to start. However, I would like to know if anyone has a link to or knowledge about an actual plot of an impedance curve for this driver in a K-horn. This is related to a crossover network some of you may have seen, and one that has given unexpectedly good performance in the mid and high frequency ranges. Chances are that RC impedance compensation is not needed in the low pass section, but I want to have a closer look. I don't have the required tools to do an impedance curve myself, and wanted to ask if someone who has the means might be willing, when convenient, to undertake that. I could pay a small fee, if that would be helpful, although what I can afford right now might not be adequate. All that is needed for this sort of compensation network is a non-polarized electrolytic cap and a resistor, and I already have the values needed. I don't want to just add the network for peace of mind if it's not really needed, but as mentioned in the other related post below, it wouldn't hurt. Thanks, Erik Quote Link to comment Share on other sites More sharing options...
Deang Posted August 15, 2007 Share Posted August 15, 2007 http://forums.klipsch.com/forums/thread/283412.aspx http://forums.klipsch.com/forums/thread/482459.aspx Quote Link to comment Share on other sites More sharing options...
Erik Mandaville Posted August 15, 2007 Author Share Posted August 15, 2007 That's all I need as far as the K-33 in the Klipschorn. Numbers alone suggested a reasonably linear response through the crossover region, and the plots confirm that. Thanks, Erik Quote Link to comment Share on other sites More sharing options...
jwc Posted August 15, 2007 Share Posted August 15, 2007 Nice find on the old threads Dean. I have the "basic" equipment to measure the "complex" impedence as ALK was describing. Right now it is all in storage so I can't piddle with it. The K33 bass reflex impedance curve looks the same. Almost right at 6 ohms even over 1000hz. Ran several 15" woofers throught this testing and some 12"....Horn loaded on some. The K33 and Crites were almost identical in this regard. Most woofers...the impedance started swinging upafter 300hz-600Hz. The K33/Crites don't. jc Quote Link to comment Share on other sites More sharing options...
DrWho Posted August 15, 2007 Share Posted August 15, 2007 Does anyone have the old Richard Heyser review of the Khorn? At least I think that was the article where a heyser spiral for the impedance was presented. If not, somewhere there is an article that perfectly describes the real and imaginary impedance for every frequency on the khorn. I can't find the article but I know it was posted on the forums. It looked like a scan of an old article because it had that faded yellow look to it. Maybe it's in the Dope from Hope? http://www.prosoundweb.com/install/sac/n26_4/nyquist/nyquist.shtml Quote Link to comment Share on other sites More sharing options...
Erik Mandaville Posted August 15, 2007 Author Share Posted August 15, 2007 Jc: That upward trend seems close to what I found based on the numbers I used. Thanks for responding. Erik Quote Link to comment Share on other sites More sharing options...
DavidF Posted August 15, 2007 Share Posted August 15, 2007 Thanks, Dr. Who for posting this reference. I never understood the presentation for this spiral imedance plot. Yes, Audio did a full analysis of the KHorn but I can not recall the volume reference. DavidF Quote Link to comment Share on other sites More sharing options...
mikebse2a3 Posted August 15, 2007 Share Posted August 15, 2007 Thanks, Dr. Who for posting this reference. I never understood the presentation for this spiral imedance plot. Yes, Audio did a full analysis of the KHorn but I can not recall the volume reference. DavidF Audio Nov. 1986 issue The Khorn Tested had the AK-2 Network, K55M and K77M so keep in mind that with different networks and drivers the impedance will vary. mike tn Quote Link to comment Share on other sites More sharing options...
DrWho Posted August 15, 2007 Share Posted August 15, 2007 Thanks, Dr. Who for posting this reference. I never understood the presentation for this spiral imedance plot. Yes, Audio did a full analysis of the KHorn but I can not recall the volume reference. Hey, no problem! There's much more info over at prosoundweb if you poke around for long enough. Interesting first post, but welcome to the forum! [] Quote Link to comment Share on other sites More sharing options...
Klipsch Employees Trey Cannon Posted August 21, 2007 Klipsch Employees Share Posted August 21, 2007 This is related to a post below re: impedance variations related to voice coil inductance of the horn-loaded K-33 woofer. Athough some effort toward impedance equalization may have been made in recent years (something I don't know), I have been searching for an impedance curve for the above woofer. I've gotten a rough estimate of the upper limit of it's response by using: Fh = expected high frequency limit; Re = voice coil DC resistance; and Le = voice coil inductance in the following formula: Fh = Re/(2piLe), which, itself, is just a point from which to start. However, I would like to know if anyone has a link to or knowledge about an actual plot of an impedance curve for this driver in a K-horn. This is related to a crossover network some of you may have seen, and one that has given unexpectedly good performance in the mid and high frequency ranges. Chances are that RC impedance compensation is not needed in the low pass section, but I want to have a closer look. I don't have the required tools to do an impedance curve myself, and wanted to ask if someone who has the means might be willing, when convenient, to undertake that. I could pay a small fee, if that would be helpful, although what I can afford right now might not be adequate. All that is needed for this sort of compensation network is a non-polarized electrolytic cap and a resistor, and I already have the values needed. I don't want to just add the network for peace of mind if it's not really needed, but as mentioned in the other related post below, it wouldn't hurt. Thanks, Erik here you go. K-33-K raw driver Doc3.doc Quote Link to comment Share on other sites More sharing options...
Guest " " Posted August 21, 2007 Share Posted August 21, 2007 This is related to a post below re: impedance variations related to voice coil inductance of the horn-loaded K-33 woofer. Athough some effort toward impedance equalization may have been made in recent years (something I don't know), I have been searching for an impedance curve for the above woofer. I've gotten a rough estimate of the upper limit of it's response by using: Fh = expected high frequency limit; Re = voice coil DC resistance; and Le = voice coil inductance in the following formula: Fh = Re/(2piLe), which, itself, is just a point from which to start. However, I would like to know if anyone has a link to or knowledge about an actual plot of an impedance curve for this driver in a K-horn. This is related to a crossover network some of you may have seen, and one that has given unexpectedly good performance in the mid and high frequency ranges. Chances are that RC impedance compensation is not needed in the low pass section, but I want to have a closer look. I don't have the required tools to do an impedance curve myself, and wanted to ask if someone who has the means might be willing, when convenient, to undertake that. I could pay a small fee, if that would be helpful, although what I can afford right now might not be adequate. All that is needed for this sort of compensation network is a non-polarized electrolytic cap and a resistor, and I already have the values needed. I don't want to just add the network for peace of mind if it's not really needed, but as mentioned in the other related post below, it wouldn't hurt. Thanks, Erik here you go. K-33-K raw driver doc3.doc is coming up blank Quote Link to comment Share on other sites More sharing options...
mas Posted August 21, 2007 Share Posted August 21, 2007 Displayed fine for me... Quote Link to comment Share on other sites More sharing options...
Guest " " Posted August 21, 2007 Share Posted August 21, 2007 20 ohms at 50hz...and thats supposed to be just the RAW driver? Quote Link to comment Share on other sites More sharing options...
WMcD Posted August 22, 2007 Share Posted August 22, 2007 On my very modest home computer it opened up in Wordpad. Gee, an Fs of 50 Hz surprised me. The magnitude of the peak might be expected. Could this be the part of a raw driver test in LMS where the driver is put in a closed box? That would account for the frequency of the peak. I'll point out something I described before. Going above Fs, the impedance curve should bottom out at the voice coil d.c. resistance which is here bottoming out at about 3.2 ohms. The plot goes down to 20 Hz and we can appoximate that if it got to 0 Hz going left, it would get to 3.2 ohms. Gil Quote Link to comment Share on other sites More sharing options...
BEC Posted August 22, 2007 Share Posted August 22, 2007 Perhaps Trey will explain the test conditions here. For the new K-33E, I get an FS of about 34 hz and on the old square magnet K-33E I get an FS of about 27 hz. That is measured in free air. Bob Crites Quote Link to comment Share on other sites More sharing options...
Klipsch Employees Trey Cannon Posted August 22, 2007 Klipsch Employees Share Posted August 22, 2007 Thats a curve I pulled from a cornwall driver. I ran it 2-3 years ago mounted in the 1/2 space door. I will look to see if I have any more info in my old files. Quote Link to comment Share on other sites More sharing options...
Klipsch Employees Trey Cannon Posted August 22, 2007 Klipsch Employees Share Posted August 22, 2007 I found one that looks right. Fs of 50Hz is wrong... k33E - Z.doc Quote Link to comment Share on other sites More sharing options...
WMcD Posted August 22, 2007 Share Posted August 22, 2007 I did a little math, which makes some sense. We see the impedance magnitude at 400 Hz is 4 ohms. That must have an inductive component because it is rising. And per the dip, the d.c. resistance is 3.2 ohms. So we can draw the triangle on a sticky pad and find the reactance is j 2.4 Then figuring for an inductance we get 0.000955 H or 0.95 mH. This looks good because we generally see the voice coil inductance of 1.0 mH. It is probably that the electrical impedance at the input to the woofer in a horn is different. I'll try to run some measurments soon. Gil Quote Link to comment Share on other sites More sharing options...
WMcD Posted August 25, 2007 Share Posted August 25, 2007 Here is info on a Belle. I would think the K-Horn would be similar at the high end, but naturally it is impossible to say for certain without a measurement. Gil Belle Woofer Imp.zip Quote Link to comment Share on other sites More sharing options...
Klipsch Employees Trey Cannon Posted August 25, 2007 Klipsch Employees Share Posted August 25, 2007 Gill, is that the raw woofer outside the cabinet? OR is that the LF of a Belle with no network? Quote Link to comment Share on other sites More sharing options...
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