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  • #16






    Quote Originally Posted by OneEng
    View Post

    Hmmm.



    It seems to me that overlapping the frequencies would cause more harm than good. You are correct that the cross-over frequency does not simply cut off everything else, but rather the cross-over point is where the cross-over has already lowered the output of that frequency by 10db (I thought). The slope of the cross-over (if adjustable) determines how rapidly the frequency drops off (typically 20db/decade to 40db/decade)




    The basic analog electronic crossover that most use has a 24 db per octave (80 dB/decade) Linkwitz-Riley (L/R) filter which is defined by its 6db down point. Set the crossover at 100hz and at 100hz the signal is 6dbs down from the rest of the bandpass. Other filter types like Bissel may be defined by their 3db down point. Crossover with bissel filters set at 100 hz will have the freq. down 3dbs. Of course there is also Fir type filters which yield very steep slopes as the yamaha speakers have. The Order of filter type determines the slope. 1st order,2order,3rd etc yields different slopes. Mixed order slopes can also be used.

    Needing to overlap or underlap or not to do it at all is all up to the overall frequency,phase,amplitude, and location of the drivers being summed.



    I used Smaart software and find its a good tool to check and align drivers.

    http://www.rationalacoustics.com/files/case3.pdf

    http://www.rationalacoustics.com/files/case6.pdf

    I tried aligning my Mains to a very loud drum monitor before and it did work quite well.



    Some good basic reading here.



    http://en.wikipedia.org/wiki/Audio_c...order_or_slope



    I did find a Underlapped alignment paper.

    http://www.excelsior-audio.com/Publi..._Alignment.pdf



    Dookietwo



    Edit: Undercool , Sorry to go off topic!

    Comment


    • #17
      I rarely find that overlapping or underlapping is necessary, desireable or productive on a reasonably well thought out speaker system. Where it MAY yield some benefit is making up for some gross flaw... like a bandaid.
      -------------------------------------------------------------------------------------------------------------------------------------------------------------------
      Former product development engineer: Genz Benz, a KMC Music/FMIC/JAM Industries Company, continuing factory level product support and service for Genz Benz

      Currently product development engineer: Mesa Boogie

      Comment


      • #18






        Quote Originally Posted by agedhorse
        View Post

        I rarely find that overlapping or underlapping is necessary, desireable or productive on a reasonably well thought out speaker system. Where it MAY yield some benefit is making up for some gross flaw... like a bandaid.




        Andy;

        What measurement system do you use when you check these well thought out systems?

        Doug

        Comment


        • #19






          Quote Originally Posted by Dookietwo
          View Post

          Andy;

          What measurement system do you use when you check these well thought out systems?

          Doug




          Note that I am making a generalization here, that most folks who "think" they need to go to such esoteric lengths in fact probably are better served addressing the more real problems. I am not saying that under some (not the majority) of applicartions there may be SOME benefit, but often this is better resolved by looking deeper into what may be the root of the problem rather than junping to this as a solution. Also, it should be noted, underlapping was much more common and necessary when BW x-over filters were more commnly used because they were not constant power summing (because of the squared factor in the power versuis voltage equation), but with LR alignments, this was handled mathamatically within the filter formulas (and IIRC the Q of the filter corner is lower).



          I usually use IASYS which superimposes coherence information within the RTA plot. I use this primarily because the testing I do to develop speaker ratings requires some method of calculating power compression and IASYS has a practical non-destructive algorithem for doing so, and outputs data in a way that my legacy management system can handle. I also use the Audio Toolkit suite for casual use but plan to do more with this as I modenize my system. I am not a great fan of Smaart (too many ways to get data that looks good but contains errors or masks problems) but when the data is good, it's just as viable as anythig else.
          -------------------------------------------------------------------------------------------------------------------------------------------------------------------
          Former product development engineer: Genz Benz, a KMC Music/FMIC/JAM Industries Company, continuing factory level product support and service for Genz Benz

          Currently product development engineer: Mesa Boogie

          Comment


          • #20
            To the OP,



            There is an engineering axiom that I personally really like:






            KISS: Keep It Simple Stupid



            For the VAST majority of users, messing around with the cross-over settings in anything other than the cross-over points is simply asking for issues.



            There are those here that are both engineers and sound professionals who can do this and achieve good results. The rest of us have a much better chance of getting worse results rather than better



            Your BEST option is to use the cross-over for both the tops and bottoms. While you are at it, it is also beneficial if you cut out everything <35-40Hz even from your subs since it is only heating up your sub voice coil.
            With Greater Knowledge Comes Greater Understanding

            Comment


            • #21






              Quote Originally Posted by agedhorse
              View Post

              Note that I am making a generalization here, that most folks who "think" they need to go to such esoteric lengths in fact probably are better served addressing the more real problems. I am not saying that under some (not the majority) of applicartions there may be SOME benefit, but often this is better resolved by looking deeper into what may be the root of the problem rather than junping to this as a solution. Also, it should be noted, underlapping was much more common and necessary when BW x-over filters were more commnly used because they were not constant power summing (because of the squared factor in the power versuis voltage equation), but with LR alignments, this was handled mathamatically within the filter formulas (and IIRC the Q of the filter corner is lower).



              I usually use IASYS which superimposes coherence information within the RTA plot. I use this primarily because the testing I do to develop speaker ratings requires some method of calculating power compression and IASYS has a practical non-destructive algorithem for doing so, and outputs data in a way that my legacy management system can handle. I also use the Audio Toolkit suite for casual use but plan to do more with this as I modenize my system. I am not a great fan of Smaart (too many ways to get data that looks good but contains errors or masks problems) but when the data is good, it's just as viable as anythig else.




              I've looked at the IASYS system. Maybe around 2007 or so. Nice unit. An all in one box that makes setups easy. Saddly the around $4000 dollar price was just too much for my wallet. Not sure of its price today. Its funtion to look at power compression is a very useable feature. Power compression is overlooked in most cases. Smaart is fine if you have a handle on what to look for and know when the measurements are not right when the results come in. A reading of 320ms delay time when your only 10 feet from a speaker needs to be redone. :-) But with time like anything you can get easy, repeatable, reliable results.

              As far as underlapped,overlapped, mulit tapped crossover filters, filter types and delay etc. Its all up to the loudspeaker designer, or user as to the best correct approach. I wouldn't say it is used to correct an inherently bad speaker system but more as a way to make them work well or behave in the band pass area they are reproducing together.

              Its becoming more and more common and a widely accepted process regardless of speaker brand or $. Processing in speakers systems is as common as electonic controling systems in most cars being driven today. Line arrays and other speaker systems use these to control directivity among other things. But I guess I'm telling you things you already know. Even the Yamaha DXR series boast of phase and time alignment in their speakers. I've heard both the DXR and DSR and they do sound good.

              As I mentioned. Underlapped or Overlapped and all the other processing that can be done to a speaker is a matter of if Done right it makes a good system better. If Done wrong then its of course a worse sounding system. Some say keep it simple which is fine. Its just what is "simple" is defined differently person to person. Some people can design a bass guitar amp while others have all they can do to plug one in. For me to keep it simple is to buy a guitar amp and settle for the features it has. For you to keep it simple is to design and build one that suits you needs with no limitations. For me setting up a speaker system using correct processing to get the results that I want from it is like you designing an amp.



              Have a Merry Christmas Andy;

              Doug

              Comment


              • #22
                You too Doug.



                I just finished writing some DSP presets for a manufacturer recently, alignment was plenty good with pretty simple processing. Starting with inherently good makes the correction process much easier and ultimately the end results better (for the most part).
                -------------------------------------------------------------------------------------------------------------------------------------------------------------------
                Former product development engineer: Genz Benz, a KMC Music/FMIC/JAM Industries Company, continuing factory level product support and service for Genz Benz

                Currently product development engineer: Mesa Boogie

                Comment


                • #23
                  Hey Doug,



                  I wasn't suggesting design specifications, but rather usage suggestions with regard to setting up a FOH system.



                  I am afraid that most people who do sound for a band wouldn't have the vaguest idea what S.M.A.R.T is



                  You guys are pretty heavy on this stuff It is nice to have such experience here.



                  Oh, and of course, Merry Christmas guys
                  With Greater Knowledge Comes Greater Understanding

                  Comment


                  • #24






                    Quote Originally Posted by OneEng
                    View Post

                    To the OP,

                    ...

                    Your BEST option is to use the cross-over for both the tops and bottoms. While you are at it, it is also beneficial if you cut out everything <35-40Hz even from your subs since it is only heating up your sub voice coil.




                    This is going to be the plan. We are going to keep, for now, the subs we have and use our crossover as previous. We DO have the rig set up to cut off those ultra LFs using the cutoff in the poweramp.



                    We toyed with picking up the 15s (based on more low end available and still delivering on the mid range clarity (or so they say)) on the chance we ever do some smaller acoustic / winery-type shows, but the 12s won out.



                    With $100 off, we can get them @ $599 ea. Tax here in the Peoples Socialist Republic of Cuyahoga County is almost 8%, but that still gets us out the door at $845.



                    Closing thoughts accepted. And thank you much for all the input and discussion.
                    Wampler SLOstortion- $175 shipped

                    Comment


                    • #25
                      One last thing.

                      I was continuing to read on this subject and came across a topic I started in 2010. Many gigs and two bands later, I am finally taking all of your advice. A few things from the answers I got back then:



                      "...at the price point of buying 2 new... I'd hold off and save more money until you could spend $500/spkr and not for the pair."



                      "Take the advice you're getting here... upgrade the speakers, go powered for mains if you can and relegate the passive stuff you have to monitor duty."



                      "That's not a very inspiring audio pile. Yes, it should work adequately for small bar gigs, etc., but you should put a priority on upgrading the speakers before upgrading anything else. Speakers make the system, period."





                      Advice TAKEN.
                      Wampler SLOstortion- $175 shipped

                      Comment


                      • #26
                        Let us know when you get them in. I think you will be very pleased with the sound of your new rig.
                        With Greater Knowledge Comes Greater Understanding

                        Comment


                        • #27
                          You will love the DXRs. All models in the line sound great (and similar) with only the low frequency response becoming more and more pronounced/extended as you move up to the bigger cabinets. It's really impressive how much performance Yamaha / Nexo are able to muster out of these cabs given the so-so components, which don't seem to be anything special. The processing is really, really good and transparent compared to some other cabs I've used.



                          Al
                          KV2 KX12s - Yamaha DXR15s, RCF ART 310A , Yamaha DXR8 - Yamaha DXS12 subs, Wharfedale Titan 12 actives, Yamaha MG12/4 mixer X 2, Peavey PV10 mixer, Yorkville PGM8 mixer - Many Sony MD players (home and portable), Shure cordless microphone and a variety of LED lighting effects.

                          Comment


                          • #28






                            Quote Originally Posted by Dookietwo
                            View Post

                            The basic analog electronic crossover that most use has a 24 db per octave (80 dB/decade) Linkwitz-Riley (L/R) filter which is defined by its 6db down point. Set the crossover at 100hz and at 100hz the signal is 6dbs down from the rest of the bandpass. Other filter types like Bissel may be defined by their 3db down point. Crossover with bissel filters set at 100 hz will have the freq. down 3dbs. Of course there is also Fir type filters which yield very steep slopes as the yamaha speakers have. The Order of filter type determines the slope. 1st order,2order,3rd etc yields different slopes. Mixed order slopes can also be used.

                            Needing to overlap or underlap or not to do it at all is all up to the overall frequency,phase,amplitude, and location of the drivers being summed.



                            I used Smaart software and find its a good tool to check and align drivers.

                            http://www.rationalacoustics.com/files/case3.pdf

                            http://www.rationalacoustics.com/files/case6.pdf

                            I tried aligning my Mains to a very loud drum monitor before and it did work quite well.



                            Some good basic reading here.



                            http://en.wikipedia.org/wiki/Audio_c...order_or_slope



                            I did find a Underlapped alignment paper.

                            http://www.excelsior-audio.com/Publi..._Alignment.pdf



                            Dookietwo



                            Edit: Undercool , Sorry to go off topic!




                            Although yes indeed overlapping is used and is commmon in getting it right, and using smaart is the way to do it...but gents I think you blew the OP

                            out of the coversation because im thinking there is no clue as to what you are talking about by the OP.

                            The most important thing here is the guy chooses the right loudspeakers for his application

                            and uses an active eq between his subs and mains.

                            Comment


                            • #29
                              Over/underlapping is common if you don't design the system right to begin with (in many cases, not all). It depends very much on the driver's out of band response. If it is rapidly rising or falling at the crossover, and especially if the crossover slopes are not steep or the Q is very low, then over-underlapping is one option to FIX the acoustic problem caused by the issues with the driver's response.
                              -------------------------------------------------------------------------------------------------------------------------------------------------------------------
                              Former product development engineer: Genz Benz, a KMC Music/FMIC/JAM Industries Company, continuing factory level product support and service for Genz Benz

                              Currently product development engineer: Mesa Boogie

                              Comment


                              • #30
                                +1 and +1
                                With Greater Knowledge Comes Greater Understanding

                                Comment













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