jcmusic Posted August 18, 2014 Share Posted August 18, 2014 Yesterday after taking some measurements of all my drivers which are well balanced across the board, I did notice that the woofer is about 4.8ms behind the mid/tweeter. Is there nothing that can be done to correct this other than going active? Did I read some where about some delay being in the xover? Quote Link to comment Share on other sites More sharing options...
Chris A Posted August 18, 2014 Share Posted August 18, 2014 (edited) Yesterday after taking some measurements of all my drivers which are well balanced across the board, I did notice that the woofer is about 4.8ms behind the mid/tweeter. Is there nothing that can be done to correct this other than going active? Did I read some where about some delay being in the xover? You can try talking to Al K. on his website, but I know of no reasonable all-pass filter designs that can produce 4.8ms delays. Digital loudspeaker processors can, however. http://www.ebay.com/sch/i.html?_trksid=p2050601.m570.l1313.TR0.TRC0&_nkw=Behringer%20DCX2496%20Ultradrive http://www.ebay.com/sch/i.html?_odkw=Behringer+DCX2496+Ultradrive&_osacat=0&_from=R40&_trksid=p2045573.m570.l1313.TR0.TRC0.H0.XElectrovoice+Dx38&_nkw=Electrovoice+Dx38&_sacat=0 http://www.ebay.com/sch/i.html?_odkw=Electrovoice+Dx38&_osacat=0&_from=R40&_from=R40&_trksid=p2045573.m570.l1313.TR0.TRC0.H0.XElectrovoice+DC-One&_nkw=Electrovoice+DC-One&_sacat=0 http://www.ebay.com/sch/i.html?_odkw=Ashly+crossover&_osacat=0&_from=R40|R40|R40&_from=R40&_trksid=p2045573.m570.l1313.TR11.TRC1.A0.H0.XAshly+processor&_nkw=Ashly+processor&_sacat=0 Edited August 18, 2014 by Chris A Quote Link to comment Share on other sites More sharing options...
Schu Posted August 18, 2014 Share Posted August 18, 2014 interested also in timing issues. Quote Link to comment Share on other sites More sharing options...
jcmusic Posted August 18, 2014 Author Share Posted August 18, 2014 Well I am just wondering if there is another way to fix the Delay with woofer other than going active. Quote Link to comment Share on other sites More sharing options...
Ski Bum Posted August 18, 2014 Share Posted August 18, 2014 Well I am just wondering if there is another way to fix the Delay with woofer other than going active. Change the actual physical location of the drivers? Much rather just use delays in an active crossover. Quote Link to comment Share on other sites More sharing options...
jcmusic Posted August 18, 2014 Author Share Posted August 18, 2014 Ski Bum I know it would be much easier to use the active controls and of course I can't move the woofer. That is the point of the thread to see if there was another way of doing it other than the two obvious ways. Quote Link to comment Share on other sites More sharing options...
Schu Posted August 18, 2014 Share Posted August 18, 2014 how would you know when it was in the correct position anyway? whenever I see aftermarket tweeters sitting on top of cabinets, they are always towards the back of the cab... tell tale? Quote Link to comment Share on other sites More sharing options...
Chris A Posted August 18, 2014 Share Posted August 18, 2014 (edited) http://pittsburghmodular.com/analog-delay/ - Hmmmm... http://en.wikipedia.org/wiki/Analog_delay_line https://www.youtube.com/watch?v=1mGFIDEqSVY http://www.amazon.com/M169-Carbon-Copy-Analog-Delay/dp/B0016ZZKJO http://www.diystompboxes.com/smfforum/index.php?topic=67671.0;prev_next=next http://forum.speakerplans.com/analog-delay-for-speaker-phase-alignment_topic60485.html I wouldn't use these, but...if you can't handle digital delays, I guess this is your alternative approach. Edited August 18, 2014 by Chris A Quote Link to comment Share on other sites More sharing options...
Schu Posted August 18, 2014 Share Posted August 18, 2014 I have no idea what I am looking at... looks like something Robert Moog would have built. 1 Quote Link to comment Share on other sites More sharing options...
Rudy81 Posted August 18, 2014 Share Posted August 18, 2014 Yesterday after taking some measurements of all my drivers which are well balanced across the board, I did notice that the woofer is about 4.8ms behind the mid/tweeter. Is there nothing that can be done to correct this other than going active? Did I read some where about some delay being in the xover? How, specifically, did you measure the drivers' time delay? 1 Quote Link to comment Share on other sites More sharing options...
jcmusic Posted August 18, 2014 Author Share Posted August 18, 2014 Yesterday after taking some measurements of all my drivers which are well balanced across the board, I did notice that the woofer is about 4.8ms behind the mid/tweeter. Is there nothing that can be done to correct this other than going active? Did I read some where about some delay being in the xover? How, specifically, did you measure the drivers' time delay? Hi Rudy, I used REW and it's impulse feature, doing one driver at a time on each side. So that's six total measurements. Quote Link to comment Share on other sites More sharing options...
jcmusic Posted August 18, 2014 Author Share Posted August 18, 2014 how would you know when it was in the correct position anyway? whenever I see aftermarket tweeters sitting on top of cabinets, they are always towards the back of the cab... tell tale? Schu, Yes towards the back because the idea is to vertically line up the voice coils. The sound stage opens up and everything kinda clears up because there is less smearing of the sound. Quote Link to comment Share on other sites More sharing options...
Rudy81 Posted August 19, 2014 Share Posted August 19, 2014 The reason I asked is that over the last few years as I have become more comfortable and slightly more knowledgeable about measurements I have noted some issues which might give you some problems. For example, if you are taking the measurements using the passive crossover, you will likely have some delays not a result of driver location. Also, I have noted that the most accurate results have resulted when I measure the drivers using the same frequency range. That is, if I measure the woofer from 50-3000khz, I need to measure the next driver up the chain in the same range.....which means, if you are measuring an HF compression driver, you need to be careful due to the low signal you will be sending to the driver. In my case, with an active crossover, I can custom tailor the tests as desired. My best results, as compared to physical measurements have been done in that manner. Granted, I am in no way an expert on the subject and have often asked more knowledgeable members for help. I just didn't want you to spend a lot of time tracking down a timing issue that may have some other factors involved than just driver distance. Quote Link to comment Share on other sites More sharing options...
jcmusic Posted August 19, 2014 Author Share Posted August 19, 2014 Hey Rudy, Thanks brother I appreciate the thought, I think I am good though even though I have a 4.8ms delay from the woofers. All six drivers measure almost exactly the same, the tweeters and mids are dead on with each other so I guess I will live with the 4.8 delay. Unless down the road i decide to go active!!! Quote Link to comment Share on other sites More sharing options...
derrickdj1 Posted August 19, 2014 Share Posted August 19, 2014 I wonder how audible a 4.8 ms delay is? 1 Quote Link to comment Share on other sites More sharing options...
djk Posted August 19, 2014 Share Posted August 19, 2014 (edited) "I wonder how audible a 4.8 ms delay is?" Depends on the frequency. At the midrage crossover point it's very audible when you fix it. Digital delay is the only fix. If the horns are deeper than the woofer, then an all-pass delay will fix it. I've done the above (balanced) with dual 12's, it's stunning. Some B&W models use the unbalanced circuit (tapped inductor on a common core). Edited August 19, 2014 by djk Quote Link to comment Share on other sites More sharing options...
jcmusic Posted August 19, 2014 Author Share Posted August 19, 2014 Ok what exactly am i looking at in your diagram? We are talking about khorns here. Quote Link to comment Share on other sites More sharing options...
minermark Posted August 19, 2014 Share Posted August 19, 2014 I have taken the step to go Active Bi-amp, and from what iv done already, i would never go back to anything less. 1 Quote Link to comment Share on other sites More sharing options...
NOSValves Posted August 19, 2014 Share Posted August 19, 2014 I wonder how audible a 4.8 ms delay is? It's a real miracle how once something is confirmed through measurements it becomes "painfully" audible to some folks.. Quote Link to comment Share on other sites More sharing options...
Marvel Posted August 19, 2014 Share Posted August 19, 2014 My math tends to be terrible, but I think at 400Hz (going from the woofer to mid, you are almost two cycles behind the mid, with one wavelength at 2.5ms.) The difference between the mid and tweeter is far more critical, as the wavelength at 4500Hz (newer Khorn crossover freq. between mid and tweeter) is a fraction over 3 inches. If the tweeter were placed on the top of the cabinet and moved to the back of the cab to line up with the K55, you can easily tell when they are lined up. Bruce Quote Link to comment Share on other sites More sharing options...
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