Deang Posted March 11, 2015 Share Posted March 11, 2015 you are free to think what ever you like, but as I told you I have no interest in anything other than showing balance. You do not like the idea I do. Works for me. As to my recommendation about the acoustic felt well you got that wrong. I recommended a layer of acoustic felt to be used as an acoustic filter. The felt goes over the woofers not on the cones. You expect me to believe that Klipsch metal cones don't ring pretty much the same as most other anodized cones do? Why don't you post some raw unsmooth response graphs that show otherwise and I will be impressed. Best regards Moray James. I don't understand your first sentence. I don't like "the idea" because it's a technical fail. Anyone that knows how to read a plot can see that for themselves. You see it too, so why are you supporting what's unsupportable? You weren't clear as to what to do with the felt. Now that you've cleared that up, would you please provide us with some supporting documention? I think you're trying to apply a room treatment solution to a driver problem that in all likelihood doesn't exist. I don't need to provide a plot - you do. Ringing/breakup modes don't normally show up on frequency response plots , but on the output generated from impulse response tests and other methods like Finite Element Analysis in conjunction with a scanning vibrometer. Klipsch changed the design of the woofers when they went to Reference IV, and the newer drivers look and behave more like Infinity's laminated CMMD woofers, where the aluminum is deeply anodized, and the ceramic penetrates a third of the cone's thickness. At this point, any ringing would be inaudible. Quote Link to comment Share on other sites More sharing options...
moray james Posted March 11, 2015 Share Posted March 11, 2015 Dean I offered my opinion and some suggestions past that I owe you no more. Felt as an acoustic filter is a very very old idea (fifty years or more)which you can research or just try it is fast easy to do and relatively inexpensive. The good news is that (and you can look this up too) is that F-11 Acoustical Felt has a very wide band of absorbency which is what makes it so useful in speaker modifications to cabinets and drivers and rooms too. My experience with metal cone drivers is that metal cone drivers do show ringing and break up modes on response graphs. Mind you my experience is decades old but I was not under the impression that aluminum was going to replace paper any time soon. I used to be part owner of a planar speaker manufacturing business (we sold through Sumo Audio of California) where we developed a small metal cone to be used as a dust cap on a 1.25" dia. voice coil, it rang like a bell and we had to stand on out heads to tame in the end we developed a polymer graphite cone and then switched to a felted paper cone which overall was the very best compromise of all. We had a very nice sota B&K system at the time to measure things on. Your information about Klipsch's new cones is very interesting and I admit I was not aware that such deep anodizing penetration processes were being used today and of that I am indeed impressed. Too bad I have to hear it from you and not from Klipsch. I still have my doubts that cone ring is inaudible but yes I am sure that it is greatly reduced. Best regards Moray James. Quote Link to comment Share on other sites More sharing options...
Deang Posted March 11, 2015 Share Posted March 11, 2015 Read the Infinity White Paper I attached a couple of posts ago, it's written in such a way that even laypersons like us can understand, and it's very good. The document was originally sent to me by Bob Gassel of Klipsch around the time the RF-7 was released -- so I knew Klipsch was watching Toole and Infinity very closely. 1 Quote Link to comment Share on other sites More sharing options...
Deang Posted March 11, 2015 Share Posted March 11, 2015 (edited) double post! Edited March 11, 2015 by Crankysoldermeister Quote Link to comment Share on other sites More sharing options...
John Warren Posted March 29, 2015 Share Posted March 29, 2015 (edited) Ringing/breakup modes don't normally show up on frequency response plots...<snip> Sure they do, just need to know what to look for. First plot is a "decay plot" of the frequency response of the K401 and the Atlas unit without a net. At t=0s (the "back-wall" of the plot) it's the on-axis, 400-10,000Hz response of the assembly and is similar to Bob's plot. The sharp, narrow peak at ~5,500Hz shown in the decay plot is a "mode" associated with non piston-like behavior. By applying crossover elements to network, the second plot, this region of the output can be attenuated and the distortion reduced as well. The downside is that a new tweeter is required, one with piston-like behavior to about 2000Hz as is a new baffle board if one intends to modify the stock Klipschorn top-end. It's a big difference with the right tweeter. A 3kHz crossover seems to do the trick. Edited March 29, 2015 by John Warren 1 Quote Link to comment Share on other sites More sharing options...
John Warren Posted March 29, 2015 Share Posted March 29, 2015 (edited) And here's how to "fill it in". The red plot is the mid horn output as the factory sets it on the older networks like the AA, A, AL, etc... There's still phase issues with this and the net is more complicated. Also, I used Dean's "two-man lift" autotransformer to attenuate the mid horn. Edited March 29, 2015 by John Warren 1 Quote Link to comment Share on other sites More sharing options...
John Warren Posted March 31, 2015 Share Posted March 31, 2015 (edited) Now also note that Beranek has considered the relationship between frequency magnitude effects and non-piston behavior in cone drivers. The numbers associated with each peak in the response correlate to the nodes shown on the second plot. Again, when you know what to look for, it's quite obvious. Scans are from Leo Beranek book, Acoustics, chapter 7. Edited March 31, 2015 by John Warren Quote Link to comment Share on other sites More sharing options...
cbarth Posted June 1, 2015 Share Posted June 1, 2015 Hi, Looking at this picture of the response graph, I was just wondering if anybody has tried a notch filter in the 1,5 to 2 khz range? Quote Link to comment Share on other sites More sharing options...
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