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  • Design process?

    Assuming the speakers are already measured (and you don't have measuring equipment) and you already have a box design what would your next step be?
    Would you run the measurements through a box modeling program and then use something like pcd to design the xo?
    Do you have to figure your baffle step out before designing xo?

  • #2
    Re: Design process?

    Response modeler takes care of BSC, edge diffraction and impedance. Assuming you rmeasured files are done so on an infinite baffle or quasi-infinite baffle that is. If they are not, then all bets are off

    So yes, make a copy of your .frd and .zma file and import them into RM and start tinkering. Enter your baffle dimensions, driver centering and driver diameter info. Save to register and RM will automatically modify the frequency response to include baffle data. From there, you save it out and then use the phase extractor on the .frd you just created. Resave it again and then import it into PCD.

    Personally, I import the traced infinite baffle file and enter the T/S parameters to generate my own .zma file. Neat trick! I model the enclosure volume and bass tuning which creates the impedance file the crossover will actually be modeled with. Not doing so can create some oddities in the crossover.

    Second, I add the modeled response to the untouched response file and merge them at 200 or 300 Hz. Then I save the .frd out and re-import it to apply baffle loss and edge diffraction. Then I save it out again and extract phase. From there it goes to PCD.

    Jeff has also included a "frequency response extender" in the latest version of RM, but I am not too comfortable explaining ow it works but I can vouch that it impacts phase quite a bit.
    Don't listen to me - I have not sold any $150,000 speakers.

    Comment


    • #3
      Re: Design process?

      Sounds good. Now all I need is to find an 8" woofer that someone has already measured.
      Planning on building a 3 way with a da175 mid and seas tweet.

      Comment


      • #4
        Re: Design process?

        http://www.zaphaudio.com/8test/

        3-way? I wish you luck - those are a PITA.
        Don't listen to me - I have not sold any $150,000 speakers.

        Comment


        • #5
          Re: Design process?

          So I've heard. I have always been good at biting off more than I can chew:D

          Comment


          • #6
            Re: Design process?

            Don't listen to Johnny- 3-ways aren't that bad. I'm sure you can do it!
            Ask if you require assistance, and I am sure lots will come to your aid.
            Later,
            Wolf
            "Wolf, you shall now be known as "King of the Zip ties." -Pete00t
            "Wolf and speakers equivalent to Picasso and 'Blue'" -dantheman
            "He is a true ambassador for this forum and speaker DIY in general." -Ed Froste
            "We're all in this together, so keep your stick on the ice!" - Red Green aka Steve Smith

            *InDIYana event website*

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            http://techtalk.parts-express.com/blog.php?u=4102

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            • #7
              Re: Design process?

              Yeah, that maybe came across as a little too discouraging. What I meant to say was: "A three way isn't a two way with a woofer".
              Don't listen to me - I have not sold any $150,000 speakers.

              Comment


              • #8
                Re: Design process?

                Originally posted by johnnyrichards View Post
                Yeah, that maybe came across as a little too discouraging. What I meant to say was: "A three way isn't a two way with a woofer".

                I think my first attempt was two two ways jammed together until they made a three way. That's what it sounded like anyway. Not so good in the mid range. I did fix it though. I ripped them back apart and crammed them and jammed them back together and now they sound much better :D.
                Dave

                and I only used my hammer once!
                http://www.pellegreneacoustics.com/

                Trench Seam Method for MDF
                https://picasaweb.google.com/101632266659473725850

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                • #9
                  Re: Design process?

                  Since you asked about the process, here are a bunch of tools
                  http://www.pvconsultants.com/audio/frdgroup.htm
                  and here's one man's approach to integrating them.
                  http://www.rjbaudio.com/Audiofiles/FRDtools.html

                  I found it useful to model an existing design, from manufacturer's data sheet through enclosure effects to crossover design and final frequency response. You've already jumped in the deep end, designing a 3-way, so just keep paddling between questions.

                  Frank

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                  • #10
                    Re: Design process?

                    Originally posted by johnnyrichards View Post
                    Yeah, that maybe came across as a little too discouraging. What I meant to say was: "A three way isn't a two way with a woofer".
                    Not at all discouraging. Ive been on the forum more than long enough to know what I'm getting myself into. I mainly just need to figure out what programs to use and how to use them properly.

                    Comment


                    • #11
                      Re: Design process?

                      Fbov thanks for the links. I had forgotten about the RJBaudio site. It answered a lot of my questions. Now all I need to do is decide what woofer I want to use. What sensitivity should I shoot for to match up with the da175? If I remember correctly The woofer can be a little more sensitive than the mid depending on where you cross and where bsc comes into play.

                      Comment


                      • #12
                        Re: Design process?

                        Next step:

                        Buy one of these:

                        http://www.amazon.com/M-Audio-Mobile.../dp/B0000TP57E

                        And then buy one of these:

                        http://www.parts-express.com/pe/show...number=390-801

                        And then download this:

                        http://www.speakerworkshop.com/ (free!)

                        And congrats, you've got measurement equipment.

                        Measure the drivers mounted in the box (one at a time and then together) and verify that what your simulation tools are telling you is accurate.
                        Best Regards,

                        Rory Buszka

                        Taterworks Audio

                        "The work of the individual still remains the spark which moves mankind ahead, even more than teamwork." - Igor I. Sikorsky

                        If it works, but you don't know why it works, then you haven't done any engineering.

                        Comment


                        • #13
                          Re: Design process?

                          Originally posted by Taterworks View Post
                          Next step:

                          Buy one of these:

                          http://www.amazon.com/M-Audio-Mobile.../dp/B0000TP57E

                          And then buy one of these:

                          http://www.parts-express.com/pe/show...number=390-801

                          And then download this:

                          http://www.speakerworkshop.com/ (free!)

                          And congrats, you've got measurement equipment.

                          Measure the drivers mounted in the box (one at a time and then together) and verify that what your simulation tools are telling you is accurate.
                          That sounds too simple :D Would that measure impedance also? I understand how a mic would would measure spl and phase but you would also need impedance measurements.

                          Comment


                          • #14
                            Re: Design process?

                            Originally posted by killa View Post
                            That sounds too simple :D Would that measure impedance also? I understand how a mic would would measure spl and phase but you would also need impedance measurements.
                            Hard to beat a woofer tester for that.
                            Don't listen to me - I have not sold any $150,000 speakers.

                            Comment

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