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Fast tracking my knowledge of compression driver and throat diameters

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  • #46
    Originally posted by devnull View Post

    Might also want to give the M2s a listen, though I think they have a more sterile/clinical sound, probably because they're designed as a monitor.

    tvrgeek - you might want to look around and see what woofers are available. The last 8" midwoofers and the last 15" woofers I bought were rated at 95dB/W and measured pretty damn close. 98+ dB/W woofers and subwoofers aren't that uncommon.
    Last I was there, they hadn't set up the M2s where you could really do critical listening. They were just kind of hanging on a random wall upstairs, with the crowd milling around. Even my GF laughed, it was like being in Best Buy. Pretty lackadaisical, I'm sure they are worth hearing.

    Downstairs is where it's at. The theater room with the S9900s, and the Revel Salon2 room are both worth the visit.
    Francis

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    • #47
      The OP wants to build a good PA system. So my point is what do we know better now than when the old crappy Altec and JBL sectoral horns were SOP 40 years ago? What has improved on their uneven, raspy and harsh sound? Throat impedance, resonances, HD, refraction, etc. Better drivers? What profile for what application? Does a throat miss-match only effect efficiency, or distortion? This is not hating horns, it is asking how to improve them where they are the appropriate technology.

      Still won't put speakers the size of a refrigerator in my living room. My ego does not need "bigger is better". Until I hear a horn based speaker than has the cleanliness and detail of my own monitors, I am not about to change my viewpoint. Hearing is believing.

      The job of a studio monitor is to tell the engineer what is wrong with the sound. The job of a living room monitor is to tell the user what is right about the sound. Different requirement, different solution. And yea, a lot of professional sound engineers are half deaf as they listened to their monitors too loud for too long. So are a large portion of musicians.

      Comment


      • #48
        Originally posted by tvrgeek View Post
        The OP wants to build a good PA system.
        Actually he is building/modifying a home listening system

        Originally posted by tvrgeek View Post
        So my point is what do we know better now than when the old crappy Altec and JBL sectoral horns were SOP 40 years ago? What has improved on their uneven, raspy and harsh sound? Throat impedance, resonances, HD, refraction, etc. Better drivers? What profile for what application? Does a throat miss-match only effect efficiency, or distortion? This is not hating horns, it is asking how to improve them where they are the appropriate technology.
        We have much better processing available, a better understanding of all aspects of performance on the part of the designers, and some improvements in driver design and manufacturing. As is often the case I think the harsh sounding horns of the past were in large part user error. That excludes the junky DJ level PA speakers systems that sounded ugly at any level, I'm referring to larger 3,4,5 way stacks that were the norm for touring bands way back when, sometimes the worst thing you could do is give a mix dude more ways to adjust and configure a system, it just turns into more ways to muck it up. I have heard some really sweet sounding horn loaded PA systems, but since getting some loudspeaker measuring tools and access to DSP I can't imagine how anybody in the past ever got even half decent results from a compression driver with just an analog crossover and 31 band EQ. The better drivers have always been better of course and the disparity between the truely good ones and the others is pretty large, I have some that are just nasty sounding and there is no fixing them, some that are not great out of the box but really come around with some processing, and others that barely need any processing. Your milage really does vary a lot with these things.
        Paul O

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        • #49
          Originally posted by tvrgeek View Post

          I think some here are getting me wrong. Horns are the first choice for some applications. Right tool for the job. I have never heard a decent horn for living room use. I have not heard every horn in the world. .
          I think this is where you are differing from many in here. There are many examples of DIY and Retail speakers that use horns and have great sound. Also examples that have iffy sound. But the ones with iffy sound are often designed that way intentionally, or simply not designed well.

          A compression driver and horn can EASILY sound just as good as a more traditional "home tweeter". In fact it can have many advantages, beyond just output level.

          Comment


          • #50
            Originally posted by Paul O View Post
            Actually he is building/modifying a home listening system



            We have much better processing available, a better understanding of all aspects of performance on the part of the designers, and some improvements in driver design and manufacturing. As is often the case I think the harsh sounding horns of the past were in large part user error. That excludes the junky DJ level PA speakers systems that sounded ugly at any level, I'm referring to larger 3,4,5 way stacks that were the norm for touring bands way back when, sometimes the worst thing you could do is give a mix dude more ways to adjust and configure a system, it just turns into more ways to muck it up. I have heard some really sweet sounding horn loaded PA systems, but since getting some loudspeaker measuring tools and access to DSP I can't imagine how anybody in the past ever got even half decent results from a compression driver with just an analog crossover and 31 band EQ. The better drivers have always been better of course and the disparity between the truely good ones and the others is pretty large, I have some that are just nasty sounding and there is no fixing them, some that are not great out of the box but really come around with some processing, and others that barely need any processing. Your milage really does vary a lot with these things.
            Agreed. I'm not sure I would have ever been happy with mine if I had to use passive crossovers. When the horn voice coil is two feet behind the woofers', there's just no substitute for digital time delay.
            Francis

            Comment


            • #51
              Originally posted by fpitas View Post
              When the horn voice coil is two feet behind the woofers', there's just no substitute for digital time delay.
              That's the reason behind the Altec A7 design. I took a different route with my horn loaded PA mains. The acoustic centers of the tweeters are in front of the woofers. That way the psycho-acoustical result is that the highs have more presence, which is a good thing in typical PA use environments. Not that I would use either A7s or my own PA tops in my home, not when I can get all the sensitivity and output I need from small driver line arrays that only extend out eight inches from the walls.

              www.billfitzmaurice.com
              www.billfitzmaurice.info/forum

              Comment


              • #52
                Originally posted by billfitzmaurice View Post
                That's the reason behind the Altec A7 design. I took a different route with my horn loaded PA mains. The acoustic centers of the tweeters are in front of the woofers. That way the psycho-acoustical result is that the highs have more presence, which is a good thing in typical PA use environments. Not that I would use either A7s or my own PA tops in my home, not when I can get all the sensitivity and output I need from small driver line arrays that only extend out eight inches from the walls.
                Well, I admit I started out just playing around, seeing what I could get a 511 horn to do. Like all hobbies it grew into a monster, and there may be other ways to do the same thing, but I like the end result.
                Francis

                Comment


                • #53
                  Originally posted by Paul O View Post

                  No 15" should be operated above 1khz. Do you own any of these drivers yet or is the project still in the planning stage? The 15+1 combo is easily the worst PA speaker design possible.. just too many compromises have to be made to get only half decent results. Of course there are commercial examples that sound way better than they have any right to(Yamaha DXR15) but that box has world class engineering expertise behind it that a DIY effort just won't match... no offence intended.. I can't do it either. There are a select few 1" drivers that can operate this low but they often tradeoff highend response to get it or the amount of SPL that can be generated goes way down.
                  You will have subs too right? If so there is no need for a 15" mid, you could downsize to 8" or 10" which will work much better with the crossover frequency needed for a 1" CD. If you're dead set on using 15's then you should be using a larger format CD to get the crossover as low as possible. With a 2" exit driver you will get vastly superior SQ with a lot less work, these larger diaphrams just perform so much better at midrange frequencies and the better examples can still produce respectable topend with some DSP help.
                  I can see where I went wrong. I should of known from the get go that with the B&C DE250 and Parts express horn that the matching woofer was a 12 inch. I mean it was more than obvious in the Econowave thread, the 15 inch was attempted and not executed. The DiySound group version threw me off. I also should of known looking at many other variants that with a 15 inch a 2 inch compression driver was needed with a larger horn but I don't know how to do these calculations, I only emulate other designs and learn from by making mistakes.

                  That said, I did mention before that I can very easily change the front baffle. I have checked and the PA Audio PH 4528 fits and I am sure I can find something similar. Also, changing the compression driver is not too hard as well. So, I will experiment with what i got and then upgrade when the chance arises.

                  The thread turned into a horn bashing one, but enough info to keep my thirst going for knowledge. Ultimately I'm keen to see how it folds out.



                  Comment


                  • #54
                    Originally posted by Trdat View Post

                    I can see where I went wrong. I should of known from the get go that with the B&C DE250 and Parts express horn that the matching woofer was a 12 inch. I mean it was more than obvious in the Econowave thread, the 15 inch was attempted and not executed. The DiySound group version threw me off. I also should of known looking at many other variants that with a 15 inch a 2 inch compression driver was needed with a larger horn but I don't know how to do these calculations, I only emulate other designs and learn from by making mistakes.

                    That said, I did mention before that I can very easily change the front baffle. I have checked and the PA Audio PH 4528 fits and I am sure I can find something similar. Also, changing the compression driver is not too hard as well. So, I will experiment with what i got and then upgrade when the chance arises.

                    The thread turned into a horn bashing one, but enough info to keep my thirst going for knowledge. Ultimately I'm keen to see how it folds out.


                    Well, one guy gave us his horn-bashing opinion, and I was dumb enough to respond. But they are hard to get right at the best of times. Lots of learning curve. The amplifier matters too if you go active; you'll hear any crossover distortion because they're so sensitive. Once they're right though, the clarity and imaging are amazing. It was definitely worth the time I spent.
                    Francis

                    Comment


                    • #55
                      Originally posted by Trdat View Post

                      I can see where I went wrong. I should of known from the get go that with the B&C DE250 and Parts express horn that the matching woofer was a 12 inch. I mean it was more than obvious in the Econowave thread, the 15 inch was attempted and not executed. The DiySound group version threw me off. I also should of known looking at many other variants that with a 15 inch a 2 inch compression driver was needed with a larger horn but I don't know how to do these calculations, I only emulate other designs and learn from by making mistakes.

                      That said, I did mention before that I can very easily change the front baffle. I have checked and the PA Audio PH 4528 fits and I am sure I can find something similar. Also, changing the compression driver is not too hard as well. So, I will experiment with what i got and then upgrade when the chance arises.
                      In your defence.. the DE250 is one of the best 1" exit drivers on the market with a very smooth sound, and in home audio applications anyway people are crossing it way low to large pro sound low/mid drivers. This is a case where you should definitely try it and see, you will know pretty quick if the combo is going to deliver what you want to your satisfaction, and then you can decide if further changes are necessary given what you have recently been made aware of.

                      Paul O

                      Comment


                      • #56
                        Originally posted by fpitas View Post

                        Well, one guy gave us his horn-bashing opinion, and I was dumb enough to respond. But they are hard to get right at the best of times. Lots of learning curve. The amplifier matters too if you go active; you'll hear any crossover distortion because they're so sensitive. Once they're right though, the clarity and imaging are amazing. It was definitely worth the time I spent.
                        So, cabinets finished and all ready to go. I tried my set up. Unfortunately my XM66 crossover has a problem so I got to take a look at it or send it back so I had to use my DBX 234xl which has a horrendous hiss, so bad that I couldn't even take a measurement for my DSP as the signal to noise ratio was in the negative range. The XM66 also had a hiss, I thought the problem was related to the cheaper DBX but it seems both gave a hum and hiss from both the woofer and tweeter.

                        My only option now is to try with digital crossovers with DSP, I just hope there is no hiss through that set up as well. UDIO-8>DAC>AMP>Speakers

                        Anyway even without a measurement correction it sounded okay, yeh of course nothing special and constrained but average. I wanted to try with an active 2 way crossover first them head into digital crossovers but it seems I have no choice.

                        Comment


                        • #57
                          Originally posted by Paul O View Post

                          In your defence.. the DE250 is one of the best 1" exit drivers on the market with a very smooth sound, and in home audio applications anyway people are crossing it way low to large pro sound low/mid drivers. This is a case where you should definitely try it and see, you will know pretty quick if the combo is going to deliver what you want to your satisfaction, and then you can decide if further changes are necessary given what you have recently been made aware of.
                          Thanks, I am in process now in trying. Without any convolution sounds average, nothing to boast about but not bad at all. Unfortunately there is so much noise in the chain that I can't even take a measurement with Audiolense. Pity, cause I know what the improvement will be with DSP. My old convolutions already open it up.

                          Anyway, I have to wait for more capacitors for tweeter protection and see how I can take a measurement or why I got this horrible hum/hiss. Iv'e never got the hang of ground loops, unless this noise is normal for the DBX?

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                          • #58
                            Put it this way, when you install a new system we know it takes time to get used to the sound and adjust. We have all had days were we judge to quick and then realise it sounds good or bad compared to first judgement. But, mostly you know if you scrap it or keep listening. 2 days I haven't reverted back to my old system so something tells me the potential is there, what it becomes of it will have to see, I am sure its a long process.

                            Comment


                            • #59
                              Originally posted by Trdat View Post

                              So, cabinets finished and all ready to go. I tried my set up. Unfortunately my XM66 crossover has a problem so I got to take a look at it or send it back so I had to use my DBX 234xl which has a horrendous hiss, so bad that I couldn't even take a measurement for my DSP as the signal to noise ratio was in the negative range. The XM66 also had a hiss, I thought the problem was related to the cheaper DBX but it seems both gave a hum and hiss from both the woofer and tweeter.

                              My only option now is to try with digital crossovers with DSP, I just hope there is no hiss through that set up as well. UDIO-8>DAC>AMP>Speakers

                              Anyway even without a measurement correction it sounded okay, yeh of course nothing special and constrained but average. I wanted to try with an active 2 way crossover first them head into digital crossovers but it seems I have no choice.
                              Equipment meant for Pro use has a tremendous amount of output available, far more than most amps need, so you can often pad the outputs to reduce the hiss.
                              Francis

                              Comment


                              • #60
                                That won't aid in the S/N department, but it's not necessary anyway. You don't hear hiss or hum through high end pro systems because they're high end. That means S/N in excess of -100dB throughout the signal chain and no unbalanced connections.
                                www.billfitzmaurice.com
                                www.billfitzmaurice.info/forum

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