John Warren Posted March 11, 2016 Share Posted March 11, 2016 (edited) Took a swag at modeling the Klipschorn bass horn. http://northreadingeng.com/Klipschorn_model/basshorn_model.htm I never really warmed up to the Horn Response software. I wanted an equivalent circuit to load filters with and a way to predict response using other drivers. Edited March 12, 2016 by John Warren 3 Quote Link to comment Share on other sites More sharing options...
ClaudeJ1 Posted March 11, 2016 Share Posted March 11, 2016 nice work, John. Quote Link to comment Share on other sites More sharing options...
Karsoncookie Posted March 11, 2016 Share Posted March 11, 2016 What's all that highfalutin gobbledygook stuff above? Sheesh. Here's yer speaker model - 1 Quote Link to comment Share on other sites More sharing options...
mikebse2a3 Posted March 11, 2016 Share Posted March 11, 2016 Interesting....... thanks for posting your work/results John....! miketn Quote Link to comment Share on other sites More sharing options...
John Warren Posted March 12, 2016 Author Share Posted March 12, 2016 What's all that highfalutin gobbledygook stuff above? Sheesh. Here's yer speaker model - perhaps the "preferred" speaker model....? Quote Link to comment Share on other sites More sharing options...
John Warren Posted March 12, 2016 Author Share Posted March 12, 2016 (edited) Getting back to the "other" model and presuming it's capturing the physics... DJK has described the Klipschorn bass horn as a 50Hz horn and the output below 50Hz due to a large woofer in a small, sealed enclosure. That is EXACTLY what the model appears to demonstrate. Edited March 12, 2016 by John Warren Quote Link to comment Share on other sites More sharing options...
Chris A Posted March 12, 2016 Share Posted March 12, 2016 Since the Khorn is a corner horn...is the extension of the bass horn due to the extended corner of the room modeled above? Is it important? Why did you pick the ca. 1948 Khorn bass bin instead of the second-generation ca. 2000 Jubilee bass bin to model? Chris Quote Link to comment Share on other sites More sharing options...
John Warren Posted March 12, 2016 Author Share Posted March 12, 2016 (edited) Since the Khorn is a corner horn...is the extension of the bass horn due to the extended corner of the room modeled above? Is it important? Why did you pick the ca. 1948 Khorn bass bin instead of the second-generation ca. 2000 Jubilee bass bin to model? Chris That's not how it was done. The actual impedance of a 1981 Klipschorn corner loaded bass unit was used as the staring point. There is no assumptions related to the horn geometry. The complex horn impedance was modeled and used to determine the model parameters. It's a reverse engineering approach. Edited March 12, 2016 by John Warren Quote Link to comment Share on other sites More sharing options...
Chris A Posted March 12, 2016 Share Posted March 12, 2016 (edited) The point is that the bass bin response in-room using different T/S parameter woofers is also a function of the loading on the woofers due to the air mass of the corner-located horns (eighth space). The only people that use the Khorn in half space are folks using false corners and locating their speakers out on the floor, like PWK did in his house. Most others are using eighth space loading. Does that affect the selection of drivers? So you didn't use a Jubilee bass bin to model because you don't have a Jubilee bass bin to measure against? I assume that the purpose of your exercise is to provide third-party upgrade parts for the Khorn bass bin? Chris Edited March 12, 2016 by Chris A Quote Link to comment Share on other sites More sharing options...
Chris A Posted March 12, 2016 Share Posted March 12, 2016 Nice electrical model... Quote Link to comment Share on other sites More sharing options...
John Warren Posted March 12, 2016 Author Share Posted March 12, 2016 (edited) I think you got it! The modeling approach simulates the complex impedance of a Klipschorn bass horn in a corner loaded location (the two woofers used were the K33E round and K33E square magnet drivers, loaded in the bass horn). The power dissipation across the radiation resistance is similar to the acoustic response measured by the factory. The factory response that I cut from the Jubilee paper is the Klipschorn bass horn response, not the Jubilee. The model is calibrated to simulate the complex impedance of the actual horn. I use Keele's approach, add frequency dependent elements to simulate voice coil and radiation resistance artifacts which avoids the need to solve the model over frequency "ranges" and tackles the whole thing head-on as a continuous function of s, the complex frequency domain variable and then it's calibrated against measurements. If the T/S parameters of any driver are known, they can be plugged into any SPICE engine and a complex impedance and frequency response can be simulated. For me, I needed an accurate electrical load to model crossover networks and this seems to do the trick. Edited March 12, 2016 by John Warren Quote Link to comment Share on other sites More sharing options...
Chris A Posted March 12, 2016 Share Posted March 12, 2016 Thanks - that last statement was the information that I was looking for: the purpose of the model itself. Was the Klipsch data taken in a hard corner in the anechoic chamber, away from the corner in the chamber with back enclosing the last fold, or some other place? Quote Link to comment Share on other sites More sharing options...
John Warren Posted March 12, 2016 Author Share Posted March 12, 2016 Thanks - that last statement was the information that I was looking for: the purpose of the model itself. Was the Klipsch data taken in a hard corner in the anechoic chamber, away from the corner in the chamber with back enclosing the last fold, or some other place? Chris-I want to say it was from the anechoic chamber given it is a factory response. Perhaps Bodcow Boy will respond given he was the principle author of the article. Quote Link to comment Share on other sites More sharing options...
Chris A Posted March 12, 2016 Share Posted March 12, 2016 I believe that he's been reincarnated as "Chief Bonehead" in his second forum life... Thanks for answering my questions. The Khorn bass bin certainly exhibits complicated behavior to the crossover/amplifier for sure. Perhaps some day I'll get a round tuit and measure the Jub bass bin complex plane input impedance--not that it will make a lot of difference to the direct-coupled amplifier driving them (Crown D75A). Maybe someone like Bob C. or Chief Bonehead already has the measurements. Chris Quote Link to comment Share on other sites More sharing options...
Khornukopia Posted March 14, 2016 Share Posted March 14, 2016 Klipschorn bass bin on PWK's workbench at CES (January) 2016. Quote Link to comment Share on other sites More sharing options...
John Warren Posted March 14, 2016 Author Share Posted March 14, 2016 (edited) The Klipschorn in WIP is some sort of attempt for the company to get back to it's roots? Here's the model predictions (square magnet K33E) for a few of the Klipschorn filters that have been used over the years. The no net (raw) needs to be "tamed" and the A and AA (series 2.5mH) was first, simple filter to do that. Perhaps too simple? so the AK, AK-2 was introduced to enhance the output in the region where it's wanted (below about 250Hz). Apparently the AK-3 was introduced to improve the output above 250Hz. How these changes correlate with mid range driver changes is not clear(?). I don't have acoustic measurements to correlate the acoustic response to the electrical behavior. And don't forget that reflections add about 10-15dB dB to the predictions and it's not uniformly added with lots of peaks. Edited March 14, 2016 by John Warren Quote Link to comment Share on other sites More sharing options...
BeFuddledinMn Posted March 20, 2016 Share Posted March 20, 2016 Outstanding John, simply outstanding work! Quote Link to comment Share on other sites More sharing options...
John Warren Posted March 20, 2016 Author Share Posted March 20, 2016 Outstanding John, simply outstanding work! Thank you sir!, I'm glad you found it of some interest. Quote Link to comment Share on other sites More sharing options...
Arkytype Posted April 6, 2016 Share Posted April 6, 2016 John, The PWK quote from THE "MAXIMUM" CORNER HORN paper where he states, "....and a means of coupling in the top and bottom sinuses,..." is curious. The modern-day Klipschorns do not utilize the volume in the top and bottom sinuses. Unless my Klipschorns purchased new in 1979 are an anomaly, there is no connecting passageway from the top and bottom sinuses to the rear air chamber. In his paper Improved Low Frequency Horn (JASA, Vol. 14, No. 3 179-182, January, 1941) PWK wrote that he did increase the volume of the rear chamber by, ...opening up the otherwise dead air spaces in the front of the cabinet lying on either side of the first horn section. Did he subsequently experiment with opening up the top and bottom sinuses? You might want to amend the Vb=V1+V2+V3 image in your paper. As you can easily see, the top and bottom sinuses are sealed to the top and bottom assembly and then with the side panels in place (covering all the pink surfaces), there is no way to couple the air from either top or bottom sinus to the rear air chamber. Lee Quote Link to comment Share on other sites More sharing options...
ssctrojan1980 Posted April 6, 2016 Share Posted April 6, 2016 Ive built a few sets of khorns. why not build the jubilee instead as the bass of the jubilee is more accurate than the single 15 of the khorn. Quote Link to comment Share on other sites More sharing options...
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