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  • 1st & 2nd Order Crossovers

    Can you use two different slopes on the same speaker. For my 3-Way set-up, can I use a 2nd order network for the mids low-pass and tweeters high-pass with a 1st order network for the mids high-pass and woofers low-pass? If so, would the crossover components for the mid-bass affect their calculated values? Would you calculate the values for the mids low-pass 2nd order, then the mids high-pass 1st order and then combine those components to construct the band-pass crossover?

  • #2
    Re: 1st & 2nd Order Crossovers

    Originally posted by sienna1 View Post
    Can you use two different slopes on the same speaker.
    I usually do. I tend to use 2nd order lowpass, as 1st order doesn't do all that much, while 3rd order is usually overkill. I use 3rd or 4th order high pass, depending how much protection the driver needs.
    www.billfitzmaurice.com
    www.billfitzmaurice.info/forum

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    • #3
      Re: 1st & 2nd Order Crossovers

      You know, if you're trying to design a 3-way, and you're not using XO simulation software, your odds of success are easily less than 1%, and most likely, ZERO.

      Biggest problem with a 1st order HP on the mid is that you'll probably be fighting that driver's resonant peak right there (exacerbated by using a closed box). Then there's that band-pass gain to contend with. Also, it's not uncommon when using 1st orders on a 3-way to end up with amp-melting impedance dips. Yikes !

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      • #4
        Re: 1st & 2nd Order Crossovers

        Originally posted by Chris Roemer View Post
        You know, if you're trying to design a 3-way, and you're not using XO simulation software, your odds of success are easily less than 1%, and most likely, ZERO.

        Biggest problem with a 1st order HP on the mid is that you'll probably be fighting that driver's resonant peak right there (exacerbated by using a closed box). Then there's that band-pass gain to contend with. Also, it's not uncommon when using 1st orders on a 3-way to end up with amp-melting impedance dips. Yikes !
        well, in his Le Singe Sarcophage, Johnny Richards showed how a 1st order highpass can work well on a sealed back mid. he used a single 8.2uf cap on a GRS sealed back mid. in a hand calculation, that would yield a 1st order butterworth crossover point of about 2400hz, but the single cap, combined the the resonant peak basically made the sealed back mid play flat to about 600hz, where IIRC it rolled off at roughly 4th order...this was how a large number of classic 70's 3 ways were designed....it really depends on the specific driver and if it was designed with this kind of implementation in mind...

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        • #5
          Re: 1st & 2nd Order Crossovers

          Can you? Absolutely and many times it is the best way to go. Many 2ways use a 2nd order on the woof and 3rd order tweet. On the 3ways I am currently working on, there is a 2nd order on the woof, a 1st order HP and 2nd order LP on the mid and 2nd order on the tweet HP. Imp does not drop much below 3.5ohms or so. This is with a 4ohm woof, 8ohm mid and 8ohm (I think) tweet.

          As Chris mentioned the mid HP can be an issue. For me its not because I am crossing around 350 and the fs on the mid is about 38 loaded into about .5 cubes sealed and stuffed.
          My Facebook audio pagehttps://www.facebook.com/pages/Mosai...3888294?ref=hl

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          • #6
            Re: 1st & 2nd Order Crossovers

            Originally posted by isaeagle4031 View Post
            Can you? Absolutely and many times it is the best way to go. Many 2ways use a 2nd order on the woof and 3rd order tweet. On the 3ways I am currently working on, there is a 2nd order on the woof, a 1st order HP and 2nd order LP on the mid and 2nd order on the tweet HP. Imp does not drop much below 3.5ohms or so. This is with a 4ohm woof, 8ohm mid and 8ohm (I think) tweet.

            As Chris mentioned the mid HP can be an issue. For me its not because I am crossing around 350 and the fs on the mid is about 38 loaded into about .5 cubes sealed and stuffed.
            I'm planning on using this application in a car environment therefore the drivers are basically working in an infinite baffle set-up. I want to keep things as simple as possible but still achieve some decent sound quality. I can go with a 3-way 1st order crossover but was trying to protect the tweeter from too much low frequency signals. I have been working around a possible 650/6500hz crossover point using Dayton Audio ND16FA-6 5/8" tweeter (FS 2000), RS75-4 3" full-range (FS 154) and RS150-4 6" woofer (FS 52). Woofer will be located forward mid-point in the doors with the other two drivers at the ends of the dash-board.

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            • #7
              Re: 1st & 2nd Order Crossovers

              I would not use a first order on that tweet unless you plan to cross it at 8k. Part of the crossover design considerations for the car need to take placement into account. You could easily cross to the mid in the 400 range and tweet in the 4k area using 2nd order slopes. This will protect the tweet much better and reduce the possibility of ringing from the aluminum cone of the mid.
              Hopefully those with more experience with those drivers can chime in.
              My Facebook audio pagehttps://www.facebook.com/pages/Mosai...3888294?ref=hl

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              • #8
                Re: 1st & 2nd Order Crossovers

                FWIW, I think you and the ND16 will be happier crossed at about 3-3.5KHz 2nd order. A lower crossover should take the "edge" off the top-end of the RS-75 and give you more of the important stereo separation cues (frequencies) "cleaner". I just worked over my Dakota's OEM stereo where mods are very limited, but changing the "super tweeters" in the upper doors to good lower freq. tweeters made a huge difference in "imaging" and overall sound quality. At any volume setting (ie 10, 11, 12 etc.) it sounds "louder", but less harsh and "fatiguing", and I can pick-out instruments and understand lyrics over road noise without blasting my eardrums out now. I are not a car stereo guy. Very far from it. I had to have the surrounds on my front speakers replaced, and the shop owner and I did some measuring. My tweeters don't "bounce" off the windshield. If yours do, that will make a difference (everything does, but the "car guys" can help more there).

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                • #9
                  Re: 1st & 2nd Order Crossovers

                  I'm going to go 1st order between the woofer/full-range and 2nd order (as suggested) between the ful-range/tweeters to reduce the harshness on the RS75 and provide better protection for the tweeter. Now it's just finding the cross-over points which will work with the drivers but not having to use odd value components which would require multiple caps/coils.

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                  • #10
                    Re: 1st & 2nd Order Crossovers

                    What do you think about these numbers:

                    Dayton Audio ND16FA-6 (high-pass 2nd order approx 4800Hz) using 2.7uF & 0.4mH
                    Dayton Audio RS75-4 (low-pass 2nd order approx 4800Hz) using 4uF & 0.25mH & (high-pass 1st order approx 500Hz) using 80uF
                    Dayton Audio RS150-4 (high-pass 1st order approx 800Hz) using 0.8mH

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                    • #11
                      Re: 1st & 2nd Order Crossovers

                      So, your coil on the RS150, pulls it down -3dB @ 500Hz, -6dB (below ref.) near 1.4kHz, then its output is -18dB @ 4.4k, rising FOURTEEN dB to only 4dB down at 9.5kHz. Should make a nice ringing sound with extra garbage the entire octave between 6 and 12 kHz.

                      Your cross points end up around 1k and 3.5k, not the 3 octaves you shot for. I've only got the tweeter running reverse polarity. Actually, it doesn't get really ugly looking until up near 4kHz (nothing that an ohm or two inline with the 3"er couldn't fix).

                      From 200Hz to 1k, your impedance straight-lines at 3 ohms. Your amp might not mind though.

                      So, the tweeter needs the most work, right now, maybe.

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                      • #12
                        Re: 1st & 2nd Order Crossovers

                        "Textbook crossover values". Sienna, please read the Speaker Building Bible sticky, then explain if your tweeter and/or mid faces towards you forward (directly at you), upwards (toward the windshield), or is pointed sideways across the cabin. With that information, and a nice word, Chris can design a cross-over for you that will sound very good. Chris is one of the best cross-over designers here. I envy his skill, knowledge and experience. (Send me that $5, Chris...;) ) Three-way cross-overs are way beyond me, and I'll admit it. My truck's sound system has built-in active X-O's and we just worked around them and "plugged the hole".

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                        • #13
                          Re: 1st & 2nd Order Crossovers

                          Originally posted by Chris Roemer View Post
                          So, your coil on the RS150, pulls it down -3dB @ 500Hz, -6dB (below ref.) near 1.4kHz, then its output is -18dB @ 4.4k, rising FOURTEEN dB to only 4dB down at 9.5kHz. Should make a nice ringing sound with extra garbage the entire octave between 6 and 12 kHz.

                          Your cross points end up around 1k and 3.5k, not the 3 octaves you shot for. I've only got the tweeter running reverse polarity. Actually, it doesn't get really ugly looking until up near 4kHz (nothing that an ohm or two inline with the 3"er couldn't fix).

                          From 200Hz to 1k, your impedance straight-lines at 3 ohms. Your amp might not mind though.

                          So, the tweeter needs the most work, right now, maybe.
                          Thank you for your valuable information.

                          The amp is rated into 2 ohms so the load shouldn't be an issue. As for the tweeters, they will be mounted in the dash along with the mids reflecting off the windshield (tweeters could be mounted in the sail panels if need be), would the ND20FA-6 be a better choice? If I left the mid-range low-pass at the current cross-over point but raised the tweeters HP 2-3k, would that help reduce the peak at 4.4k and lessen the ringing? I'm just trying to replace the current OEM speakers with ones that will provide a bit more detail and sound that's easier on the ears without the whole project becoming too complex.

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                          • #14
                            Re: 1st & 2nd Order Crossovers

                            Here are my suggestions:

                            to:
                            Dayton Audio ND16FA-6 (high-pass 2nd order approx 4800Hz) using 2.7uF & 0.4mH
                            - lead off with a 1ohm resistor, change the series cap to 3uF, change the coil to 0.30mH
                            tweeter gets wired reverse polarity

                            to:
                            Dayton Audio RS75-4 (low-pass 2nd order approx 4800Hz) using 4uF & 0.25mH & (high-pass 1st order approx 500Hz) using 80uF
                            - the High Pass is actually the series cap, put it out front and increase it to 100uF, then . . .
                            the Low Pass is a series coil followed by a shunt cap (to ground). The 4uF cap is OK, but
                            change the coil to 0.15mH AND add a small 1.5uF cap across (in parallel with) its leads - this helps suppress the high freq. "ringing"

                            to:
                            Dayton Audio RS150-4 (high-pass 1st order approx 800Hz) using 0.8mH
                            - change coil to 1.2mH and parallel it with an even tinier cap, this one 0.10uF - for the ringing on the 150
                            also add a "Zobel" across the woofer's terminals, which is a 3Ω resistor and 10uF cap in series (with each other)


                            The (now) LARGER coil on the RS150, still pulls it down -3dB @ 500Hz, -6dB (below ref.) is now at 1.0kHz (instead of 1.4k)Hz, then its output is -24dB @ 4.4k (previously -18), rising only 5dB to the "hash" at 6k, putting it NOW at -19dB (instead of -4dB) with an additional spike at 9kHz now being @ -21dB, seventeen dB lower than previously. These peaks (6k/9k) are now down greater than -24dB and -30dB compared to an unfiltered driver (where their levels are actually ABOVE reference by "about" +8dB). Not the prettiest I ever saw, but not as ugly as before.

                            Someone said this was for autosound - somehow I missed that. That MUST screw up the phase between the woofer and the mid-tweet pair, because of different locations, right? I don't do autosound, so your mpg may vary.

                            Chris

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                            • #15
                              Re: 1st & 2nd Order Crossovers

                              Originally posted by Chris Roemer View Post
                              Here are my suggestions:

                              to:
                              Dayton Audio ND16FA-6 (high-pass 2nd order approx 4800Hz) using 2.7uF & 0.4mH
                              - lead off with a 1ohm resistor, change the series cap to 3uF, change the coil to 0.30mH
                              tweeter gets wired reverse polarity

                              to:
                              Dayton Audio RS75-4 (low-pass 2nd order approx 4800Hz) using 4uF & 0.25mH & (high-pass 1st order approx 500Hz) using 80uF
                              - the High Pass is actually the series cap, put it out front and increase it to 100uF, then . . .
                              the Low Pass is a series coil followed by a shunt cap (to ground). The 4uF cap is OK, but
                              change the coil to 0.15mH AND add a small 1.5uF cap across (in parallel with) its leads - this helps suppress the high freq. "ringing"

                              to:
                              Dayton Audio RS150-4 (high-pass 1st order approx 800Hz) using 0.8mH
                              - change coil to 1.2mH and parallel it with an even tinier cap, this one 0.10uF - for the ringing on the 150
                              also add a "Zobel" across the woofer's terminals, which is a 3Ω resistor and 10uF cap in series (with each other)


                              The (now) LARGER coil on the RS150, still pulls it down -3dB @ 500Hz, -6dB (below ref.) is now at 1.0kHz (instead of 1.4k)Hz, then its output is -24dB @ 4.4k (previously -18), rising only 5dB to the "hash" at 6k, putting it NOW at -19dB (instead of -4dB) with an additional spike at 9kHz now being @ -21dB, seventeen dB lower than previously. These peaks (6k/9k) are now down greater than -24dB and -30dB compared to an unfiltered driver (where their levels are actually ABOVE reference by "about" +8dB). Not the prettiest I ever saw, but not as ugly as before.

                              Someone said this was for autosound - somehow I missed that. That MUST screw up the phase between the woofer and the mid-tweet pair, because of different locations, right? I don't do autosound, so your mpg may vary.

                              Chris
                              Thank you very much, I'll draw a schematic and post just to confirm my interpretation of your instructions. I know a car environment is probably one of the worst for decent sound but I think the change will be much better than the present set-up. :D

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