Members RoadRanger Posted June 19, 2010 Author Members Share Posted June 19, 2010 Last DSP programming I worked on was for the F-35 :Xm7_PPE-8nk http://www.jsf.mil/Woo Hoo !Them guys were REALLY anal about testing boundary conditions for sure . Link to comment Share on other sites More sharing options...
Members agedhorse Posted June 20, 2010 Members Share Posted June 20, 2010 My college roommate was an aeronautical/mechanical engineer and went into the AF as an engineer/test pilot. The other engineer here was an instrumentation engineer for NASA on the Apollo projet. The parent company I work for had an aerospace division as well, and there's a darn good reason for why design and testing procedures are so thorough and complex. There's a lot that can go wrong, and there's a lot of possible conditions to consider, so testing involved a wide range og both conditions and variables... a lot of permutations. Link to comment Share on other sites More sharing options...
Members RoadRanger Posted June 21, 2010 Author Members Share Posted June 21, 2010 I hooked it up to my laptop today using "Visual Analyzer":http://www.sillanumsoft.orgThe frequency response of the 3 filters I had was quite a bit off from what Behringer's software predicted so I tweaked it in using pink noise. I ended up with these three:20Hz 37/60 octave -48db20Hz 37/60 octave -48db100Hz 80/60 octave +16dbLooks like a very nice 24db/oct 100hz HPF now .However I'm a bit perplexed as to the locked filter behavior I saw the other day. Now any locked filters return to single shot mode upon a short power cycle or if you switch to another preset and then switch back. Neither of those actions would clear them before . Link to comment Share on other sites More sharing options...
Members Dookietwo Posted June 21, 2010 Members Share Posted June 21, 2010 I hooked it up to my laptop today using "Visual Analyzer": http://www.sillanumsoft.orgThe frequency response of the 3 filters I had was quite a bit off from what Behringer's software predicted so I tweaked it in using pink noise. I ended up with these three: 20Hz 37/60 octave -48db 20Hz 37/60 octave -48db 100Hz 80/60 octave +16db Looks like a very nice 24db/oct 100hz HPF now . However I'm a bit perplexed as to the locked filter behavior I saw the other day. Now any locked filters return to single shot mode upon a short power cycle or if you switch to another preset and then switch back. Neither of those actions would clear them before . Does your software show phase as well? 2 48db per octave filters in series gives you a 96db per octave slope. The amount group delay may be quite great. I wonder if it rings as well? Dookietwo Link to comment Share on other sites More sharing options...
Members RoadRanger Posted June 21, 2010 Author Members Share Posted June 21, 2010 Ah, I was wondering when the "phase police" would raid this thread . Does your software show phase as well?No. 2 48db per octave filters in series gives you a 96db per octave slope. The amount group delay may be quite great. I wonder if it rings as well?They are not 48 db/oct filters - they are bandpass filters with a 20Hz center frequency, a 37/60 octave bandwidth, and set for -48db of cut.I suspect the phase gets pretty squirrelly at and below 100hz but as it's not a crossover there isn't another driver "below" its frequency cutoff that I have to match up to so I'm not all that worried about it . Link to comment Share on other sites More sharing options...
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