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3-Way Active - High WAF - Hi-Vi-Fas

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  • #31
    Re: 3-Way Active - High WAF - Hi-Vi-Fas

    Looks great! I'm glad I made the transition to spraying automotive urethanes, and I suspect you are, too. The quality of finish is just a lot nicer than what you can get through normal DIY means.

    I may have missed it, but what are you using for amps?

    I'm very interested to hear about how the XO development goes, I was seriously tempted to build my last pair of floorstanders (Zaph ZDT3.5 variant) as an active set, but chose not to for the time being - the next set, however, will be worth the time to experiment with.

    -Sam

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    • #32
      Re: 3-Way Active - High WAF - Hi-Vi-Fas

      Originally posted by phidauex View Post
      Looks great! I'm glad I made the transition to spraying automotive urethanes, and I suspect you are, too. The quality of finish is just a lot nicer than what you can get through normal DIY means.
      Thanks! Yes, moving away from spray paint was the best thing I ever did. I'm only upset that I didn't move to HVLP'ing earlier. I wasted a lot of time trying to get spray paint even a fraction as good as what I get now much easier. Just bought a new house, and unfortunately the builder chose an ugly kitchen cabinet color. Just spent 2 days masking off the kitchen from the rest of the house, and sprayed this same white onto the cabinets. Looks great.


      Originally posted by phidauex View Post
      I may have missed it, but what are you using for amps?
      Not sure yet, I have a nice a/d/s 6 channel car amp that I've used before with a 55 amp power supply. Sounds really good. I suspect adding a small 12v atv or motorcycle battery to the chain could be even better.
      I also have 3 AMP One's that I could use (they're a bit underpowered IMHO).
      Last option is a pair of crowne CTS 4200 4 channel amps. That could be a bit overkill.

      Originally posted by phidauex View Post
      I'm very interested to hear about how the XO development goes, I was seriously tempted to build my last pair of floorstanders (Zaph ZDT3.5 variant) as an active set, but chose not to for the time being - the next set, however, will be worth the time to experiment with.
      Yah, XO development will probably take up a lot of time. I'm trying to teach myself to use ACD, but I keep getting frustrated and dead ending. I need to upgrade my brain. That said, I have a lot of experience tuning by ear and using RTA in the car audio environment with active crossovers, so I've gotten ~ 80% there with just generic-ish settings. The main challenge that is new to me that I haven't directly addressed in the car environment is phase interaction of drivers.

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      • #33
        Re: 3-Way Active - High WAF - Hi-Vi-Fas

        Originally posted by devinkato View Post
        ...The main challenge that is new to me that I haven't directly addressed in the car environment is phase interaction of drivers.
        1. Measure woofs only, (with filter.)
        2. Measure midrange only, (with filter.)
        3. Now measure woof and mid at same time, (with filters)
        4. Repeat #3 with midrange driver reversed phased.

        Now look at all four plots at the same time. You'll probably see either that either #3 or #4 produces some acoustic cancellation due to the drivers' phase. Typically one of these will be much better than the other. Welcome to the world of "Phase". LOL.

        Ok, what happens if #3 and #4 are both problematic and the woofers are not blending well with the mid? (Adding properly at some frequencies, but cancelling at other freqs.) That's the challenge of crossover design. It means that the combination of drivers and filters is not exactly in phase, nor exactly out of phase. At this point I would try changing one of the two filters to have a slightly different slope, which will affect the phase... and possibly get the woofers and midrange summing properly.

        By overlaying 3 measurements: just woofers, just midrange and the acoustic combination of them, it becomes clear where the drivers are adding and where they are cancelling due to phase. Make some adjustments and repeat... make some more adjustments and repeat.

        Hope this helps.

        P.S. - use the exact same methodology for midrange to tweeter crossover design, except that you'll be keeping the midrange polarity that you determined already, and you'll be changing the tweeter's polarity until you get the drivers to sum properly.
        Last edited by ReissM; 12-05-2012, 09:25 PM.
        ~Marty

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        • #34
          Re: 3-Way Active - High WAF - Hi-Vi-Fas

          ReissM - that's exactly what I've been doing in the car over the years. Glad to know I'm doing something right!

          Proper phase is really easy for my ear to find - it usually makes a big difference in terms of something "shouting" and blending.

          As far as drivers - am I correct in understanding that the closer you push a driver towards its frequency limits, that is where you start seeing more unpredictable phase issues? Like the "not exactly in phase, nor exactly out of phase" phenomenon you describe?

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          • #35
            Re: 3-Way Active - High WAF - Hi-Vi-Fas

            Originally posted by devinkato View Post
            ...am I correct in understanding that the closer you push a driver towards its frequency limits, that is where you start seeing more unpredictable phase issues?
            1. acousticacoustic
            still
            ~Marty

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            • #36
              Re: 3-Way Active - High WAF - Hi-Vi-Fas

              Originally posted by ReissM View Post
              Hmmm... I'm not sure I fully understand what you're asking. The phase summing/cancelling issues are a result of several things.
              Forgive my ignorance - I do know that drivers' distortion increases as they're pushed towards their frequency limits. Is phase also affected in the same way? Is it harder to integrate drivers' phase summing when they're being pushed towards their frequency limits?

              I know that all normal crossovers also introduce phase issues, I was referring more to the phase issues that the drivers themselves introduce.

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              • #37
                Re: 3-Way Active - High WAF - Hi-Vi-Fas

                Originally posted by devinkato View Post
                Forgive my ignorance...
                Whoa... time out. No need to apologize. We're all just amateurs here on TT forum. If I came across as an expert, then I apologize to YOU. I was just expressing a few of my own personal opinions based on my past experiences. Please continue to ask questions and learn from everyone here on TT.


                Originally posted by devinkato View Post
                ... I do know that drivers' distortion increases as they're pushed towards their frequency limits. Is phase also affected in the same way? Is it harder to integrate drivers' phase summing when they're being pushed towards their frequency limits?

                I know that all normal crossovers also introduce phase issues, I was referring more to the phase issues that the drivers themselves introduce.
                That's a very intelligent question. I don't have all the answers... but let's take a look at the acoustic phase of your woofer. I took the CLIO data that PE posted and plotted the phase. The "180 degree wrapping" typically seen on phase plots can be misleading, so I unwrapped the phase plot and a trend emerges that seems to follow your intuition. Take a look at how little the phase changes until we approach approximately 7,000 Hz. At 7,000 Hz the rate-of-change of the acoustic phase increases dramatically. This appears to corroborate what you suspected.

                Click image for larger version

Name:	Phase-1 (HiVi B4N).JPG
Views:	1
Size:	25.7 KB
ID:	1145439
                ~Marty

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                • #38
                  Re: 3-Way Active - High WAF - Hi-Vi-Fas

                  The woofer's voice coil inductance will play some role in this too. Exactly what... I'm not sure.

                  Anybody else want to add some insight to this discussion of acoustic phase?
                  ~Marty

                  Baby Eidolons
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                  • #39
                    Re: 3-Way Active - High WAF - Hi-Vi-Fas

                    Originally posted by devinkato View Post
                    As far as drivers - am I correct in understanding that the closer you push a driver towards its frequency limits, that is where you start seeing more unpredictable phase issues? Like the "not exactly in phase, nor exactly out of phase" phenomenon you describe?
                    I not sure what you mean either...
                    "Not a Speaker Designer - Not even on the Internet"
                    “Pride is your greatest enemy, humility is your greatest friend.”
                    "If the freedom of speech is taken away, then dumb and silent we may be led, like sheep to the slaughter."

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                    • #40
                      Re: 3-Way Active - High WAF - Hi-Vi-Fas

                      Originally posted by ReissM View Post
                      ... but let's take a look at the acoustic phase of your woofer. I took the CLIO data that PE posted and plotted the phase. The "180 degree wrapping" typically seen on phase plots can be misleading, so I unwrapped the phase plot and a trend emerges that seems to follow your intuition. Take a look at how little the phase changes until we approach approximately 7,000 Hz. At 7,000 Hz the rate-of-change of the acoustic phase increases dramatically. This appears to corroborate what you suspected.
                      [ATTACH=CONFIG]31493[/ATTACH]
                      I suspect this is one of the reasons that I've had more success with 3-way systems (other than polar response). I'm simply not pushing the drivers to their limits as much as in a 2-way, therefore I'm avoiding funky driver induced phase summing issues combined with crossover point phase issues.

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                      • #41
                        Re: 3-Way Active - High WAF - Hi-Vi-Fas

                        My previous phase graph showed the acoustic phase of your woofer. Here's the electrical phase of the raw driver (usually displayed along with the impedance curve). Notice that the electrical phase doesn't do anything drastic as we approach 7,000 Hz like the acoustic phase did.

                        Click image for larger version

Name:	Phase-2 (HiVi B4N) Electrical.JPG
Views:	1
Size:	40.4 KB
ID:	1145442
                        ~Marty

                        Baby Eidolons
                        Sapphos
                        Cables (Post #54)
                        Other speakers (Post #21)
                        Design Thoughts (Posts: 6,10,13,33,35)
                        Boundary Augmentation
                        Dispersion/Interference

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                        • #42
                          Re: 3-Way Active - High WAF - Hi-Vi-Fas

                          Been a while since my last update. Here's what's gone down!

                          Realized I wasn't going to have time to teach myself the fine arts of pouring decorative concrete, so I decided to go with a wood base.

                          I wasted a day fabricating my first idea - a double thick .75" mid "sleeve" stand. I then test fit the speaker to the stand, and realized that it looked terrible. The stand was too chunky and broke up the thin "flow" of the speaker.



                          After that, I went back to basics, and used .5" MDF to make a sleek and thin stand that has a base of 10 inches. This kept the overall aesthetics I was looking for, and I painted it in gloss black to match the terminal plate.





                          All done - the build at least. Now is the hard part - tuning.



                          Last edited by devinkato; 02-27-2013, 07:39 PM.

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                          • #43
                            Re: 3-Way Active - High WAF - Hi-Vi-Fas

                            Wow, that's a clean setup. Very nice so far!

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                            • #44

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                              • #45
                                Re: 3-Way Active - High WAF - Hi-Vi-Fas

                                Thanks for the feedback - When you say "makes baffle influence strong", in dumb ppl terms - what does that mean? That the width/height of the baffle will play a larger role on the frequency response and will have to be addressed via crossover design?

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