sfogg Posted December 30, 2006 Author Share Posted December 30, 2006 -1.5 dB @ 3.18kHz Q10 Quote Link to comment Share on other sites More sharing options...
sfogg Posted December 30, 2006 Author Share Posted December 30, 2006 Same as before but with rear cover removed from the driver just to see if/how it alters response... Quote Link to comment Share on other sites More sharing options...
bodcaw boy Posted December 30, 2006 Share Posted December 30, 2006 hey shawn, impressive. i think that the ability to verify your mods is very important and you obviously have that. is the freq scale linear? roy delgado Quote Link to comment Share on other sites More sharing options...
sfogg Posted December 30, 2006 Author Share Posted December 30, 2006 In the attached ZIP file is a Quicktime movie of the spectrum analyzer while performing a 30 second sweep from 500hz to 20kHz. For those that don't know what they are looking at basically the big peak is the fundamental, IOW the frequency that is being played by the Peavey. Smaller peaks above the fundamental that move with the fundamental are harmonic distortion. The chain here is my HP function generator feeding the Behringer DCX2496 to the Teac tripath to the Peavey and then through the mic pre-amp and to the Spectral Dynamics analyzer. Not the easiest to see in the Quicktime but it gets the point across. Shawn peavey.zip Quote Link to comment Share on other sites More sharing options...
sfogg Posted December 30, 2006 Author Share Posted December 30, 2006 In the Quicktime the scale of the measurment is 40kHz so one could see at least the second order harmonic at 20kHz. 3rd or 4th order distortion wouldn't be seen on the analyzer as they would be above the range of the instrument. The other thing one can look for on this is resonance in the driver. If the driver had a resonant peak you should see the fundamental jump way up when the sweep hits the resonant frequency. Also note the couple of big dips in the fundamentals response up high. That mirrors the earlier FR measurements done with a noise source. Shawn Quote Link to comment Share on other sites More sharing options...
sfogg Posted December 30, 2006 Author Share Posted December 30, 2006 Hi Roy, Thanks, the analyzer certainly makes it easier to see what is going on and to setup the EQ easier. I wouldn't want to go down this road without the measurement equipment. The scale is linear on those pictures. 10dB per division vertical. The horizontal scale is linear as well but the frequency per division varies depending upon how wide I'm looking at. Shawn Quote Link to comment Share on other sites More sharing options...
DrWho Posted December 31, 2006 Share Posted December 31, 2006 So how does it sound? All the measurements look quite impressive. Any ideas on what the dip ~16kHz is? I take it on the last series of plots that each horizontal division is 2kHz wide? Quote Link to comment Share on other sites More sharing options...
sfogg Posted December 31, 2006 Author Share Posted December 31, 2006 Mike, Only listened to noise so far. Sounds likenoise. I need to work on the crossover next. For the listeningtests I'll probably just use the stock amp. If/when I integrate theseinto the system for good I'll need to do some work on my modded Teacsto maximize SNR out of the Behringers DACs by altering the fixedattenuation I have in them. I also altered the Teacs to lower theirnoise floor as they had too much hiss driving the speakers directly.That may or may not need to be changed, it is sort of a tradeoffbetween hiss and power. The natural rolloff in the CD horn might helphide the hiss and since I need more power for the EQ I might need toturn their power back up. Not sure about the dip at 16kHz, I have one or two things I want to try and if it makes a difference I'll post it. On the 20kHz range pictures the horizontal divisions are 2kHz wide. Shawn Quote Link to comment Share on other sites More sharing options...
PrestonTom Posted December 31, 2006 Share Posted December 31, 2006 Shawn is that dip at 16kHz real? Or is there the waveform slapping against something about an inch away from the mic (a mic stand etc). The dip seems fairly prominent. -Tom Quote Link to comment Share on other sites More sharing options...
sfogg Posted January 1, 2007 Author Share Posted January 1, 2007 Tom, Not sure yet. I've moved the horn/driver and mic a few times and I think that dip has stayed pretty consistent. When I get a chance I'll do some more placements to see if it sticks around or not. Shawn Quote Link to comment Share on other sites More sharing options...
Deang Posted January 1, 2007 Share Posted January 1, 2007 The spec sheet looks good on it but I saw a post either on AA or the Lansing site from a guy that measured the 850 and basically said it was the worst 2" driver he had ever measured. As such I crossed that one off the list. Man, you crossed a driver off your list based on the comments of one guy? That's atypical behavior for you -- an anomaly in your response. Quote Link to comment Share on other sites More sharing options...
ZAKO Posted January 1, 2007 Share Posted January 1, 2007 Yeh the new Radian 950 ...They claim its a TAD killer ...5 slit phase plug & a clone diaphram. The Radian marketing is blowing smoke rings. Quote Link to comment Share on other sites More sharing options...
djk Posted January 1, 2007 Share Posted January 1, 2007 "a guy that measured the 850 and basically said it was the worst 2" driver he had ever measured." It didn't measure all that bad in the high end, but it didn't sound good either. Worst measuring 2" (not counting cheap junk you know isn't going to be any good), the RCF N850. Quote Link to comment Share on other sites More sharing options...
sfogg Posted January 1, 2007 Author Share Posted January 1, 2007 DJK, I'm pretty sure you were the guy I saw that had made that post on AA about how poorly it measured. I must have mistaken the RCF 850 for the Radian 850 though. Have you tried the Peavey? Any other reasonable priced suggestions to try if the Peavey doesn't work out? Thanks, Shawn Quote Link to comment Share on other sites More sharing options...
DrWho Posted January 1, 2007 Share Posted January 1, 2007 I've heard a lot of great things about the B&C drivers (yes, even before I found out Klipsch uses some of them)...If I had the money right now that's the approach I would be trying. Of course, I have absolutely no experience with any of them [] If I had a lot of money I think TAD would be the way to go. Quote Link to comment Share on other sites More sharing options...
TBrennan Posted January 1, 2007 Share Posted January 1, 2007 Best large format driver I've heard is the JBL 2435---better than the 4001, better than 2440-whatevers---even better than the 288. A pal uses them on old Community radial horns. Top end to die for. Quote Link to comment Share on other sites More sharing options...
sfogg Posted January 1, 2007 Author Share Posted January 1, 2007 Tom, Thanks, I'll keep an eye out of the Peavey doesn't work out. Those have the Be diaphragms in them don't they? Shawn Quote Link to comment Share on other sites More sharing options...
TBrennan Posted January 1, 2007 Share Posted January 1, 2007 Shawn---Yup, 3" BE diaphragm, neo magnet, 1.5" exit. Used in the Vertec arrays. There are a couple of guys that sell them used on ebay once in a while for about $200-250 each, a bargain I think. That's where my pal got his. And Jammin Jeresy has them too but their price is dearer. If I wanted to go large format they're the way I'd go,no doubt in my mind. Quote Link to comment Share on other sites More sharing options...
DrWho Posted January 1, 2007 Share Posted January 1, 2007 Does JBL make their own drivers? In other words - any hope of trying to source similar drivers from an OEM? Quote Link to comment Share on other sites More sharing options...
Erik Mandaville Posted January 2, 2007 Share Posted January 2, 2007 Hey, Shawn: This is an interesting experiment, and I'm interested to know how measurements compare with listening to music, dialogue, effects, and so forth. And also, of course what your perceptions are in terms of differences and improvements (if that happens to be the case) over what you're using now. I'm also curious about the more sort of mundane or mechanical -- but nevertheless-still-important -- aspects concerning mounting applications and techniques. In terms of the purely visual aspect of this change, these new horns are more understated and less obvious, and subsequently might be better for HT. And you're right, my mind sometimes still finds itself stuck in two channel stereo. I forgot about the the third La Scala bin in the middle. I shared email with Jon Risch years and years ago when I had a severe case cable-making flu. Have fun! Erik Quote Link to comment Share on other sites More sharing options...
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