Al Klappenberger Posted March 26, 2001 Share Posted March 26, 2001 Hi guys. The picture below is an item up for bids now (March 26, 2001) on eBay: http://cgi.ebay.com/aw-cgi/eBayISAPI.dll?ViewItem&item=1224869985 I have not been able to confirm it from the seller yet, but I think all these drivers are the later version of the K55V having the phase plug modification done by PWK to smooth the frequency response. These can be identified by solder-on connections rather than push-on connections. If this is the case it represents 4 sets of drivers for home stereo speakers! The pictures seem to show solder-on connections, but I can't tell for sure. The price is probably going to go to high for me to buy it just to get one set of two. If four of us get together and buy it as a group, we could all divide the drivers between us (2 each at least). Would anybody else be interested if I can confirm that they are the later versiom K55V? Al K Quote Link to comment Share on other sites More sharing options...
Tony Reed Posted March 26, 2001 Share Posted March 26, 2001 I'll go in for the horns. Tony Quote Link to comment Share on other sites More sharing options...
Klewless Posted March 26, 2001 Share Posted March 26, 2001 Al, You can count on me for a pair of the drivers, if the price remains reasonable. I will accept your judgement for definition of "reasonable". John ------------------ John P St Paul, MN Quote Link to comment Share on other sites More sharing options...
Al Klappenberger Posted March 26, 2001 Author Share Posted March 26, 2001 Tony , John, Email me and we can decide what "reasonable" actually is to be. I still haven't heard from the seller. I will bug him again. alk@ezy.net Al K. Quote Link to comment Share on other sites More sharing options...
Al Klappenberger Posted March 26, 2001 Author Share Posted March 26, 2001 Hi guys. JACKPOT ! Here is a closeup of the connections provided by the seller. I am pretty sure they ARE the new revision K55V drivers. Al K Quote Link to comment Share on other sites More sharing options...
Allan Songer Posted March 27, 2001 Share Posted March 27, 2001 Sure, Al--coun't me in for 2 drivers and 1/4 of the cost if you need me. You can never have too many "spares." Quote Link to comment Share on other sites More sharing options...
JohnA Posted March 27, 2001 Share Posted March 27, 2001 Those ARE the late drivers. I have 2 of those and one of the early K-55-Vs. I can't hear a difference other than the fact that the newest late driver has less output than its twin. I have had the disphragm replaced and found the voice coil was rubbing apparently from abuse. John Quote Link to comment Share on other sites More sharing options...
John Warren Posted March 27, 2001 Share Posted March 27, 2001 What the big deal with these drivers?? I've got a pr of them on LaScalas I don't think they sound a any different than the K55M (they all suck). There is no magic fix here---> you need a midrange with a bigger throat. it physics nothing else, stop fooling yourselves Quote Link to comment Share on other sites More sharing options...
Al Klappenberger Posted March 27, 2001 Author Share Posted March 27, 2001 John, You might be right about not being able to hear the difference. PWK himself said virtually the same think in a "Dope from Hope" outlining the phase plug chage. I think it will ultimatly cost less than the K55M. As to the bigger throat, If you are going to have the same taper and start with a biger throat, you must wind up with a bigger mouth. How am I going to get that into a Belle Klipsch? Al K. Quote Link to comment Share on other sites More sharing options...
John Warren Posted March 27, 2001 Share Posted March 27, 2001 From a price perspective maybe, considering that the LLC wants $186 for the K55M. Regarding fit into Belle....A bigger horn won't fit, you have to mount it outside the enclosure. Quote Link to comment Share on other sites More sharing options...
djk Posted March 28, 2001 Share Posted March 28, 2001 >>John Albright Those ARE the late drivers. I have 2 of those and one of the early K-55-Vs. I can't hear a difference other than the fact that the newest late driver has less output than its twin. I have had the disphragm replaced and found the voice coil was rubbing apparently from abuse. << The K55V with solder lugs sounds better than the ones with spring loaded terminals because the connections can't vibrate.The Atlas PDMR, the Atlas model designation for the new phase plug design, both measures and sounds different than the K55V. >>John Warren What the big deal with these drivers?? I've got a pr of them on LaScalas I don't think they sound a any different than the K55M (they all suck).There is no magic fix here---> you need a midrange with a bigger throat. it physics nothing else, stop fooling yourselves<< We are in total agreement.These drivers are from the MCM1900 which originally used the Gauss HF4000 2" throat midrange driver.My favorite 2" midrange driver for the K/B/LS is the Community Light and Sound M200 ftp://ftp.voicenet.com/communit/specs/new/m200.pdf This driver sounds much better than the current crop of titanium 2" stuff.>>Al Klappenberger As to the bigger throat, If you are going to have the same taper and start with a biger throat, you must wind up with a bigger mouth.<< For the same taper rate if you start out with a bigger throat you end up with the same mouth area and a shorter horn.Done it many times with the K400.See figure 5.11 in Acoustical Engineering by Olson.Shows a 100hz horn with different throat sizes.Absolute best horn reference book. Quote Link to comment Share on other sites More sharing options...
JohnA Posted March 28, 2001 Share Posted March 28, 2001 There's a lot of stuff I can't hear or can't hear easily in the room I use. However, I have seen the Dope from Hope introducing the solder terminal -V and it's response curves. The latest -V is obviously smoother than the previous one and has better output from 4k - 6k. That's why I went to the trouble to find a second solder-terminal driver. I expected to hear something, but didn't. Maybe if I had 2 of each and swapped both at once, I'd hear it. Why does Klipsch use such a small throat in the K-400? When I first saw it I thought it looked too small, but I barely understand the physics. Is the small throat a way of getting a horn with a 263 Hz cut-off in the space alotted? If the throat were larger and the length the same (with a small increase in mouth size, perhaps) would the cut-off rise to an unacceptable frequency? Specifically, what does the small throat do to sound (velocity too high?)? John Quote Link to comment Share on other sites More sharing options...
Al Klappenberger Posted March 28, 2001 Author Share Posted March 28, 2001 John, I am NO horn expert, but as I understand it, a longer horn has it's first discontinuity at a lower frequency. The narrow throat makes the horn longer. A big throat is only necessary for extreme power levels. The big throat means a bigger driver which requires a bigger voice coil and that limits the high frequency end. PWK knew what he was doing! Al K. Quote Link to comment Share on other sites More sharing options...
John Warren Posted March 29, 2001 Share Posted March 29, 2001 Al-It's air movement. large diaphragm (large throat) moves less for a given SPL. small diphragms like K55M strains at moderate levels results in air compression instabilitites at throat=distortion. You hear what goes on in the throat in a mid horn because your ear is at max sensitivity in that region. The Khorn mid cannot reproduce strings or solo piano at moderate SPLs without appreciable distortion. djk recommends to hack a few inches of the Klipsch K400 and mount 2" compresion unit. I've not heard this setup but it is reasonable and in the right direction. an adapter of some type is needed and if you have a plastic horn it might not be feasible. throwing away the OEM crossovers and replacing with other units isn't a viable fix IMO. Like auto engines, there is no substitute for cubic inches. PWK has admitted that the mid-range is a tough nut to crack and it is evident in the many variations in the horn over the years. I don't really know why PWK held on to the K55-series driver for so long, maybe it was some sort of passion but pice gets high when compression drivers get large. Quote Link to comment Share on other sites More sharing options...
oosting Posted March 29, 2001 Share Posted March 29, 2001 OK, what exactly is an air compression instability? BTW, the speed of sound in air at a given temperature, pressure and humidity is a CONSTANT. Ed Quote Link to comment Share on other sites More sharing options...
John Warren Posted March 29, 2001 Share Posted March 29, 2001 Compression instability (also termed "air overload distortion"): 2cnd Harmonic distortion caused by the non-linear relationship between pressure and volume of the air in the throat of the horn as it undergoes adiabatic compression and expansion. Mathematically-- %2nd Harmonic distortion = <1.73(F/Fc)I>x10^-2 where: F= driving frequency Fc = cut-off frequency I = throat intensity (watts/sq.cm) So Ed, as you state the speed of sound in air for a given temperature, pressure and humidity is a constant....now that I've explained compression instability can you explain this statment and were it was supposed to take us? Quote Link to comment Share on other sites More sharing options...
MacKlipsch Posted March 29, 2001 Share Posted March 29, 2001 To Oz to see the Wizard Quote Link to comment Share on other sites More sharing options...
MacKlipsch Posted March 30, 2001 Share Posted March 30, 2001 Anyway kids...sorry to get back to the thread topic....Do you have enough folks to split these drivers Al? Quote Link to comment Share on other sites More sharing options...
Al Klappenberger Posted March 30, 2001 Author Share Posted March 30, 2001 Hi driver fans. Fred, YES We got everything accounted for with backups for the drivers in case somebody backs out. Only one person interested in the raw horns though. Al K. Quote Link to comment Share on other sites More sharing options...
Ray Garrison Posted March 30, 2001 Share Posted March 30, 2001 John, Plugging different values into the formula you provided: %2nd Harmonic distortion = <1.73(F/Fc)I>x10^-2 where: F= driving frequency Fc = cut-off frequency I = throat intensity (watts/sq.cm) seems to indicate that the % 2nd harmonic is going to be very, very low for most of the range of the driver, but I have no idea what the watts/sq.cm value refers to. I mean, the sq.cm is, I assume, the cross sectional area of the horn's throat, but where? At the point just in front of the driver, or at the narrowest point, or somewhere else? Also, what are "watts" ? Acoustic power output? Electric power input to the driver? Am very curious... Thanks for the informative posts, by the way... Ray ------------------ Music is art Audio is engineering Quote Link to comment Share on other sites More sharing options...
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