DrWho Posted November 6, 2006 Share Posted November 6, 2006 If the problem is there with multiples of drivers, then it would have to be the horn... I remember Roy telling me about the Khorn and PWK's research on it. At some point in time they sent off an engineer to recreate the khorn inch for inch without the bends in it (so basically the exact same area expansion rate). The measured frequency response came to +-1dB instead of the +-5dB of the folded khorn (if I remember correctly). I can't imagine why the same wouldn't be true for the Jubilee....they just did a better job of folding to make it less of an issue. Quote Link to comment Share on other sites More sharing options...
mikebse2a3 Posted November 6, 2006 Share Posted November 6, 2006 Jubilee with EV Dx38 Frequency Response that Roy posted for Richard and I. note: The low end rolloff shows the Jubilee wasn't in the corner of the anechoic chamber for this plot. mike tn Quote Link to comment Share on other sites More sharing options...
DrWho Posted November 6, 2006 Share Posted November 6, 2006 Thanks Mike! And man that's sexy except for the 200Hz dip...(maybe I shouldn't be saying that about speakers while I'm still single....) [][] I can handle a dip at 200Hz though...nothing but mud and cardboard in that frequency range anyway...unless you're looking for that snare drum "thwack" that Duke is always talkin about. Quote Link to comment Share on other sites More sharing options...
mikebse2a3 Posted November 6, 2006 Share Posted November 6, 2006 Thanks Mike! And man that's sexy except for the 200Hz dip...(maybe I shouldn't be saying that about speakers while I'm still single....) [][] I can handle a dip at 200Hz though...nothing but mud and cardboard in that frequency range anyway...unless you're looking for that snare drum "thwack" that Duke is always talkin about. As often happens graphs can look worse than they sound. Notice that the Jubilee LF Response fits within a +/- 3db range down to 65Hz in this plot. Note to anyone not familiar with the Jubilee that when properly placed the Corner Loading and Room Gain will increase The Low Frequency Extension thats missing in this plot. This is a very smooth response especially when you realize this is for an extremely High Efficiency System! mike tn[] Quote Link to comment Share on other sites More sharing options...
D-MAN Posted November 6, 2006 Share Posted November 6, 2006 The thing drops like a rock below 60Hz! Am I missing something here? Other than that, yes, quite impressive the rest of the way up. Brings up a problem, this type of speaker cannot be effectively measured outside of a room corner, and therefore, everyone ends up literally testing the room with the enclosure in it. A nasty little thing... Add to that where, exactly, does one measure it from. Most use 3 meters and "adjust" from there. It ain't the same if you don't actually SIT and LISTEN at exactly 3 meters... DM Quote Link to comment Share on other sites More sharing options...
bodcaw boy Posted November 6, 2006 Share Posted November 6, 2006 you guys are close.....hint: look at the curve miketn posted....... boy Quote Link to comment Share on other sites More sharing options...
bodcaw boy Posted November 6, 2006 Share Posted November 6, 2006 "complicated by the path length of the horn being too short?" Well, the physical horn is 140cm. The calculated horn is 191cm. The actual mouth being the "room". I don't understand the significance of "shortening" it to 140cm instead of say 155cm. Who has a good article for this? I see your point about impedance swings possibly causing the dips so when I get home...I guess I should look at the impedance curves...However....I don't recall any impedance swings to account for the response that I am seeing. The Back turn of the jub bin is the really one area that I don't have the greatest grasp for. The other turns are easy for my me to visualize. I will probably buy some mirrors to check how things are reflected back there. don't think mirrors; think water pipes...... It doesn't matter the driver I put in there. Same type of phenomenon. I didn't post the third set of drivers I put in there which was the cheaper Pioneer ones that I think BFDay has in his clone. They are a tad weaker under 100Hz and drop after 350Hz. However, the original Pioneers I have and the E. Kappas look pretty similar except the Kappas don't have the low end. So......It's the horn...IMO. I would like to be able to "fix" the drop after the 200Hz out of principle only....It sounds good otherwise. jc Quote Link to comment Share on other sites More sharing options...
PrestonTom Posted November 6, 2006 Share Posted November 6, 2006 ...... As far as the measurements provided by Klipsch - the manner in which they are measured is known and not a variable. .... Mike, In all fairness, that is wishful thinking. As soon as you put hardware into an anechoic chamber it is no longer anechoic. Anechoic chambers are not anechoic at low frequencies (I won't get into the details about lower cut off frequencies). Exactly "how" is the 1/8 space created? As soon as you plug in the spectrum analyzer (or whatever) there are decisions (and not necessarily explicitly made by you) about windowing, filtering, averaging etc. These are not trival and depend on the signal being used. What is the signal: tone, tone pips, narrow band noise, frequency sweeps (ala TDS)? Or are they "time domain measres (TDS TEF, MLS) in which case there is a series of other questions. Once the data were obtained, what was the filtering, averaging and windowing? There really are a number of variables that are chosen or tweaked to generate these plots. I would not conclude that the procedure is "known" nor would I conclude that is the best. I am not being hostile. It is simply the case that measurement is not a trivial issue. I have worked around sound proof rooms, reverberant rooms and anechoic chambers for the last couple of decades. The worst thing you can do is to simply "believe" the numbers that the (your favorite brand here - HP, Techtronix, SRS etc) machine is putting out. There are a number of things that are "massaging" the data. My original comment was that the measure was of a "speaker in a room". What is measured is a function of the speaker, of the room, of the method (sustained signal used by the RTA) , of the set up (where the mic was placed etc) and how the data were "handled" (how does RTA set up the signal , window the measurements, and average the output). Given all these issues, why would anyone jump in and attribute the various "squiggles" to the speaker rather than the room, measurement, averaging etc. ? I am not beating up on you, but it really is not a trivial issue. -Tom Quote Link to comment Share on other sites More sharing options...
bodcaw boy Posted November 6, 2006 Share Posted November 6, 2006 tom, are you talking about making measurements in a room or a chamber? boy Quote Link to comment Share on other sites More sharing options...
PrestonTom Posted November 6, 2006 Share Posted November 6, 2006 I was mostly referring to the room measures. However, even in the chamber measures, how the spectrum analzer, test signal etc is set up certainly does matter. It was always amazing how much "detail" was smeared over by "selecting" a different, test signal, averaging and window. Obviously you are familar with this headache, but I was concerened that some folks may have a blind faith about the numbers that the "analyzer" is cranking out and not considering the details. -Tom Quote Link to comment Share on other sites More sharing options...
bodcaw boy Posted November 6, 2006 Share Posted November 6, 2006 when we setup the equipment to measure in our chamber, we went thru several tests to convince ourselves that the resolution of the different tests could be repeated time after time and with as much resolution as we could get (obviously you can get to the point of dimishing returns). because of the chamber, we expected some relief from from types of measurement systems. so when we do a freq test for example, whether we use an MLS, tef or just a swept sine wave to excite the speaker, we do expect the graphs to look like each other barring some small error and to look like that today and next week. we did the same for the 1/2space and 1/8 space measurement confirming that we weren't fooling ourselves into a comfort zone of errors. so as to whether i would consider a measurement in a chamber to be a "known", i would have to say (given measurement setup specs like 2.8 v at 1m, tweeter axis,etc), "pretty close" as i would expect to see pretty much the same curve in other chambers. now room measurements, all bets are off.....[] Quote Link to comment Share on other sites More sharing options...
jwc Posted November 6, 2006 Share Posted November 6, 2006 Hmm. Maybe it isn't the horn or the room for the 200Hz dip. Somebody said something about multiple drivers? Hmm? Well. Guess what. I pulled the bottom pioneer driver out and put in the drone w/o any weights on it. So one drone and one Pioneer driver. Same position of mic on the floor at one meter. I changed my SPL axis to Relative SPL. The top end won't make it to 1000Hz. No surprise. However, not as much "dipping" as with the dual drivers instead of one with a drone. The low end looks a little better too. Quote Link to comment Share on other sites More sharing options...
jwc Posted November 6, 2006 Share Posted November 6, 2006 "don't think mirrors; think water pipes......" Roy...Dude...I think about water pipes every day man. Quote Link to comment Share on other sites More sharing options...
mikebse2a3 Posted November 6, 2006 Share Posted November 6, 2006 you guys are close.....hint: look at the curve miketn posted....... boy The first flare rate for the Jubilee if I remember is 97Hz I believe so 97Hz x 2 =194Hz and 97Hz x 3 = 291Hz which seems to approximately correspond with some of the peaks we are seeing. ROY, Am I Cold or Hot with this guess? mike tn[] Quote Link to comment Share on other sites More sharing options...
Deang Posted November 7, 2006 Share Posted November 7, 2006 I did duct design for HVAC systems for a few years -- I've sometimes wondered if some of the same things apply. I'll risk wearing the dunce cap and say that maybe that dip is caused by static pressure loss. Quote Link to comment Share on other sites More sharing options...
chops Posted November 7, 2006 Share Posted November 7, 2006 Speaking of alternative designs, has anyone ventured into doing an open baffle design at all with dual 15's per channel? With the right drivers, one can easily match the sensitivity ( <105dB 1w/1m) of the squawker, get excellent, clean midrange up to 600Hz and natural, ultra-fast and dynamic bass to an extent before implementing active EQ'ing to compensate for the dipole roll-off in the lowest octaves. This is exactly what I have in the works at the moment. I'm doing some research just to "freshen up" before jumping in head first. This ought to be some fun times coming up soon! [] Quote Link to comment Share on other sites More sharing options...
Duke Spinner Posted November 7, 2006 Share Posted November 7, 2006 I did duct design for HVAC systems for a few years -- I've sometimes wondered if some of the same things apply. I'll risk wearing the dunce cap and say that maybe that dip is caused by static pressure loss. ' ooooohhh, really, Dean ...... maybe the Jub is designed at .05" drop ... Quote Link to comment Share on other sites More sharing options...
Duke Spinner Posted November 7, 2006 Share Posted November 7, 2006 and the Drivers can produce .1" t.s.p. Quote Link to comment Share on other sites More sharing options...
Deang Posted November 7, 2006 Share Posted November 7, 2006 LOL! Quote Link to comment Share on other sites More sharing options...
bodcaw boy Posted November 7, 2006 Share Posted November 7, 2006 "don't think mirrors; think water pipes......" Roy...Dude...I think about water pipes every day man. I FORGOT!!! Quote Link to comment Share on other sites More sharing options...
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