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Peerless SVS buyout aluminum woofer and SB26 STAC - the SVS STAC

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  • Peerless SVS buyout aluminum woofer and SB26 STAC - the SVS STAC

    I picked up these drivers from augerpro and after some months of cabinet construction and a Tarkus build for my uncle, as well as some MiniDSP listening, I have the following to show and tell, and then to ask the crossover gurus for some pointers of what could be improved.

    Here are the PCD shots. I've used the FRD Blender 2.0 to blend nearfield and the farfield measurements to provide my response. It still looks like it rolls off at 100 or so, but my REW shows it rolling off around 60, which is what my Unibox model predicted. I'm using a sealed cab as they will be used with a sub. In my listening with the MiniDSP I found about 1600 LR4 to be pretty solid, with no audible (to me) signs of strain out of the tweeter, even at elevated listening levels, prob 90+ db at the listening position.

    Click image for larger version

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    The driver offset was measured using delay with REW which came up with .027m or just over an inch which seems about right for a 180mm woofer.

    Click image for larger version

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    The woofer filter ended up just 2 parts, I did a notch (I think) which you can see, but it didn't drop the resonance much further so I figured it wasn't worth it to add in.

    Click image for larger version

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    The tweeter filter was just me playing with values until it was flat and where I could drop the hump around 1500 to meet the filter target. Not really sure how what I did work, but seems to have worked here. If not, someone tell me!

    Click image for larger version

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    The overall response ended up pretty good with a nice reverse null that took quite a few iterations to get.

    Click image for larger version

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    Impedence graphs here - note the lower octaves have a rising impedence which in a previous thread was likely caused by crosstalk using the UCA222 DAC and a DIY impedence jig.

    I will add some more photos of the cabs and drivers later.

    Thanks all for looking and let me know what other things I should try. I didn't really hear too much difference in using different crossover points other than when I crossed higher, there was some ringing from the woofer (I muted the tweeter and the woofer separately to listen to differences). Any tips on critical listening would also be appreciated as I figured I should probably notice SOME differences!

    All thoughts and advice and changes welcome!!


  • #2
    Also, is there a different way to post pics that would make it easier to scroll through?

    Comment


    • #3
      Originally posted by scottvalentin View Post
      I picked up these drivers from augerpro and after some months of cabinet construction and a Tarkus build for my uncle, as well as some MiniDSP listening, I have the following to show and tell, and then to ask the crossover gurus for some pointers of what could be improved. Here are the PCD shots. I've used the FRD Blender 2.0 to blend nearfield and the farfield measurements to provide my response. It still looks like it rolls off at 100 or so, but my REW shows it rolling off around 60, which is what my Unibox model predicted. I'm using a sealed cab as they will be used with a sub. In my listening with the MiniDSP I found about 1600 LR4 to be pretty solid, with no audible (to me) signs of strain out of the tweeter, even at elevated listening levels, prob 90+ db at the listening position. [ATTACH=CONFIG]n1351308[/ATTACH] The driver offset was measured using delay with REW which came up with .027m or just over an inch which seems about right for a 180mm woofer. [ATTACH=CONFIG]n1351309[/ATTACH] The woofer filter ended up just 2 parts, I did a notch (I think) which you can see, but it didn't drop the resonance much further so I figured it wasn't worth it to add in. [ATTACH=CONFIG]n1351310[/ATTACH] The tweeter filter was just me playing with values until it was flat and where I could drop the hump around 1500 to meet the filter target. Not really sure how what I did work, but seems to have worked here. If not, someone tell me! [ATTACH=CONFIG]n1351311[/ATTACH] The overall response ended up pretty good with a nice reverse null that took quite a few iterations to get. [ATTACH=CONFIG]n1351312[/ATTACH] Impedence graphs here - note the lower octaves have a rising impedence which in a previous thread was likely caused by crosstalk using the UCA222 DAC and a DIY impedence jig. I will add some more photos of the cabs and drivers later. Thanks all for looking and let me know what other things I should try. I didn't really hear too much difference in using different crossover points other than when I crossed higher, there was some ringing from the woofer (I muted the tweeter and the woofer separately to listen to differences). Any tips on critical listening would also be appreciated as I figured I should probably notice SOME differences! All thoughts and advice and changes welcome!!
      That parallel leg in the tweeter circuit is really driving the impedance low up there. It's going to go even lower as frequency goes up and could cause amp problems. I'd either omit that entirely or raise the 0.5 ohm resistor up to 4 or more. Typical Zobels are more like 10 ohm. Otherwise you're doing at least as good as I could ;) Sent from my SM-G920P using Tapatalk
      Electronics engineer, woofer enthusiast, and musician.
      Wogg Music

      Comment


      • #4
        Hmm that resistor (and cap) is what tilted the response down to get it flat. I'll play with it tomorrow to see what will work. I didn't even know that was a zobel...

        Comment


        • #5
          It also looks like that Zobel padded the tweeter down significantly too. Add a series network and play with straight resistance, and possibly a parallel inductor / resistor combo to shape the tweeter response. I tend to play with that before or after the network, whichever allows me to track phase closer and keep a good reverse null.
          Electronics engineer, woofer enthusiast, and musician.
          Wogg Music

          Comment


          • #6
            Yes I used that resistant to pad it - will try some more ways to play around with it then.

            Comment


            • #7
              The tweeter looks p*ssed off around 1500hz, I would guess the distortion is high. I would cross higher. I work with the SB tweets
              often and they are awesome when properly implemented.

              Comment


              • #8
                At 1500 THD is less than .5% and at -55db and only starts rising below 1200. Plus I couldn't hear anything off. I have tried crossing higher and didn't notice much of a difference. But I will try a few more iterations with the MiniDSP as well, so will do one at 1800 and one at 2200 and see how the off axis matches up.

                Comment


                • #9
                  Ok i've moved the crossover point up to what looks like 1800 or so, got the impedence to stay above 5 ohms at all points. Added some normal series resistance as well for tweeter padding rather than just the zobel.

                  Any further comments? Chuck isaeagle4031 since you've the tweeter before, any ideas to try, or is this looking do-able? wogg and xmax thanks for your input so far!

                  Attached Files

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                  • #10
                    Well I made a crucial error in my offsets that makes all of the above moot. I had the woofer offsets in the tweeter column so I've had to start over with the crossover.

                    I have a nice flat response but can't get phase anywhere close though. Will post the sim later this morning.

                    Comment


                    • #11
                      Here is the error in the first attachment:
                      You can see in the tweeter column I have the vertical and z offsets there, and 0's in the woofer.

                      The next attachments have corrected the error:
                      It seems to have worked out fairly well (I think?) Crossed around ut. Can anyone tell me if I've made any other errors or if I can start adding parts to my cart?

                      Also, I've never "voiced" a speaker. Any methods, tips, first things to play around with? What parts should I change out?

                      One other thing, I turn on "Polar Active" and do the off-axis plots, but then the whole system response changes and the phase changes. The screenshots attached here are before I do the off axis calcs. After I hit that button, I can't get the phase to line up and I need to make changes to get the sum back to a flat response as it always ends up with a dip in the crossover region.


                      Attached Files

                      Comment


                      • #12
                        Here is what i used for approx 2k xo point. Used a different woofer that was recessed far. If u have the parts on hand its worth a shot. Rev polarity on the tweeter.
                        My Build Thread's
                        Carrera's / Finalist TL's / Speedster TMM's / Speedster MTM Center / Overnight Sensation Surrounds

                        Comment


                        • #13
                          Based on that last sim, I think you need a bit more bsc. I would increase the woofer inductor to 1.8-2mh. You will also need to slightly increase the tweeters level a bit as well.
                          https://www.facebook.com/Mosaic-Audi...7373763888294/

                          Comment


                          • #14
                            Thanks Chuck - I have these going fairly close to the wall when they are done and so I was not shooting for full bsc.

                            Any other observations? It's $80 ish bucks of crossover parts so I don't want to start ordering just yet without some confirmation that the bases are covered and this is a reasonable start to my first crossover design.

                            Comment


                            • #15
                              Originally posted by isaeagle4031 View Post
                              Based on that last sim, I think you need a bit more bsc. I would increase the woofer inductor to 1.8-2mh. You will also need to slightly increase the tweeters level a bit as well.
                              Quoted you for the tag so you'd see the above comment. Thanks for the input so far.

                              Comment

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