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  • Lambda Speaker Thread

    Hi Everyone,

    Way back I was considering building a pair of OB speakers. I solicited opinions from experienced DIY'ers and everyone was kind to offer help. The thread can be found in the Forum asking for XO help and recommendations for drivers. This is a continuation of sorts but with Pics.

    I finally decided on a sealed woofer (10 inch Dayton RS270). I am "reusing" Dynaudio 17W75's (zero cost) and a SB29 tweeter.

    The enclosure is made from 13 ply Maple and lined with 1/4 MDF on the interior and braced and Acoustical clay will be strategically placed to reduce vibration. The wood is lacquered. Once the speaker is to my liking (soundwise) I will veneer them.

    The panels are individually removable so it is a test baffle of sorts. The XO sections (HP,BP,HP) will be on induvidual boards and accessible for modification.

    Thanks go out to Eric (mdocod) for doing the simulation. This project probably would not have gotten off the ground if not for his hard work. And to Paul Carmody Your Sunflowers were the inspiration for this design (as you can see).


    I am now going to try to upload pics. I will periodically update with new pics.
    Attached Files

  • #2
    Re: Lambda Speaker Thread

    More PicsClick image for larger version

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    • #3
      Re: Lambda Speaker Thread

      Original Thread was here http://techtalk.parts-express.com/sh...r-Dayton-RS270

      Comment


      • #4
        Re: Lambda Speaker Thread

        Only recommendation I have is the chamfer on the back of the woofer hole. Other than that it looks really nice

        रेतुर्न तो थे स्रोत
        return to the source
        leviathan system thread
        deadhorse thread
        shockwave build thread

        instagram :: greywarden_13

        in war, victory . . . in peace, vigilance . . . in death, sacrifice.

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        • #5
          Re: Lambda Speaker Thread

          Originally posted by greywarden View Post
          Only recommendation I have is the chamfer on the back of the woofer hole. Other than that it looks really nice
          Absolutely in the plan, just haven't gotten to it yet. Thanks. I also seen foam used on the back as well.

          Comment


          • #6
            Re: Lambda Speaker Thread

            Hi Jim,

            Everything looks really good. There's a tiny discrepancy...

            The driver cut-outs don't appear to be in the positions simulated, but the effect will be minimal in this case. I can see how my description of the driver positions from the crossover thread could be misinterpreted to mean something else. I expect, based on some quick sim, that the change in position on the baffle will result in some up-to +/-1dB variations from the simulated response in the 500-4000hz range. No big deal really.

            I am excited to hear your impression of the speakers once the speakers are loaded and all wired up.


            ---------------

            for those interested:

            Simulated response:








            Regards,
            Eric
            Pro/Fi Cinema Speaker project: "From the Ashes"

            Comment


            • #7
              Re: Lambda Speaker Thread

              DAYUM that's a crossover haha

              रेतुर्न तो थे स्रोत
              return to the source
              leviathan system thread
              deadhorse thread
              shockwave build thread

              instagram :: greywarden_13

              in war, victory . . . in peace, vigilance . . . in death, sacrifice.

              Comment


              • #8
                Re: Lambda Speaker Thread

                Wow- 5th electrical on the tweeter (I've only done that once)...4th electrical on the woofer... and 1st electrical on the midrange.

                Not saying they won't sound good, nor that they aren't simmed nicely; but I feel you could have gotten by with fewer parts overall or at least a less costly set of parts.

                Keep us posted!
                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*

                Photobucket pages:
                http://photobucket.com/Wolf-Speakers_and_more

                My blog/writeups/thoughts here at PE:
                http://techtalk.parts-express.com/blog.php?u=4102

                Comment


                • #9
                  Re: Lambda Speaker Thread

                  Hi Wolf,

                  I'm sure you have found yourself in situations where the drivers, or the baffle, or some combination of things about the system winds up forcing you into more components than one would like. From the outside looking in, I have no doubt that this looks nuts, but if you saw the response that I was starting with, it would make more sense... I don't doubt a more experienced designer could probably achieve something as good with less components, I just am not there yet

                  The 4th order on the bottom is both BSC and low pass rolled in together. Hitting reasonably symmetrical slopes, while smashing down the metal cone break-up, while crossing in phase lead me here. I could not find a better way. Shallow component configurations killed phase alignment, and didn't give me enough control to shape the response through the x-over region to mate up with the bizarre response from the open baffle loaded midbass.

                  The midbass driver, in this case, being open baffle, had a very strong baffle wrap hump in response, followed by a natural steep decay. I feel almost lucky to have found what is effectively a 1st order and a pad, with some additional shaping via an LRC to be "enough" to knock down the horrendous starting point of the response here. Keep in mind, that we're knocking down a ~8dB peak, and a ~5dB peak in response, level matching, knocking down breakup, and protecting the driver from over-excursion, with just 6 components on the bandpass.... That's not bad considering the excess of mess to clean up here.

                  The 5th order on the high pass for the tweeter was the only way to get a reasonable slope shape and grade match to the midbass driver's natural rolloff combined with it's low pass, while holding reasonable phase alignment.

                  Fun stuff

                  Here's crossing fingers that the result is is within +/- 1-2dB of simulation. If it works out that way, it should be a pretty impressive speaker.

                  Regards,
                  Eric
                  Pro/Fi Cinema Speaker project: "From the Ashes"

                  Comment


                  • #10
                    Re: Lambda Speaker Thread

                    I agree that the midrange circuit is very minimalist- and if it works it's a great thing!

                    Yeah- I've used more than my fair share of parts at times I wager;
                    -Sometimes to see what it does...
                    -Sometimes because you have to...
                    -Sometimes to minimize every nook and cranny in the response...

                    Personally, I strive most of the time to use what is necessary (just as you have apparently done here) and keep it simple while respecting that.
                    'KISS with respect to necessity', as I always say....

                    FWIW- even though this is not a Duelund alignment it does a lot of the same things. Steep on the tweeter and woofer, and 1st order shallow on the mid.
                    It's just another method of design- as their are many!

                    Crossing my fingers with ya!
                    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*

                    Photobucket pages:
                    http://photobucket.com/Wolf-Speakers_and_more

                    My blog/writeups/thoughts here at PE:
                    http://techtalk.parts-express.com/blog.php?u=4102

                    Comment


                    • #11
                      Re: Lambda Speaker Thread

                      Eric,
                      I believe the schematic is incorrect for the mid. You have a coil for HP instead of a cap (I think you meant to put band 11 in series behind the band 10 cap?), and a cap then coil for LP, those should be reversed I believe. Also Band L10 says 900uH. Sorry, please correct me if I am mistaken. It just looks off to me.
                      HAGD,
                      Marc

                      Even though I try to tell everyone upfront, understand that I am still a Newb. I wish the status of Seasoned Veteran/Senior Member, etc. was earned with time not posts...

                      TMWW thread

                      Maurbacs DCR Tower

                      Comment


                      • #12
                        Re: Lambda Speaker Thread

                        Eric!! ACK! Doh! where were the mid/tweet locations?! (I believe the woofer is correct 14 inches from bottom)

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                        • #13
                          Re: Lambda Speaker Thread

                          Hi Marc,

                          I believe you are confusing the intent of the bandpass components in this particular case. The unusual looking values of components in series with the mid-bass driver, are actually there to both correct for response issues related to the open baffle, output level, and natural response of the driver, while also serving to electrically, acoustically, and mechanically restrict the driver from undesired operation.


                          Regards,
                          Eric
                          Pro/Fi Cinema Speaker project: "From the Ashes"

                          Comment


                          • #14
                            Re: Lambda Speaker Thread

                            OK so I went back to the original thread and found the mid was supposed to be cenetered 36 inches from the bottom. and the tweeter right above it. Its not too far off, I don't have the measurements with me but I am going to guess that the mid is 32 inches (so I am off by 4 inches) Might be for naught if i dont like the Dynaudio as others have been stating.

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                            • #15
                              Re: Lambda Speaker Thread

                              Originally posted by jimbones View Post
                              OK so I went back to the original thread and found the mid was supposed to be cenetered 36 inches from the bottom. and the tweeter right above it. Its not too far off, I don't have the measurements with me but I am going to guess that the mid is 32 inches (so I am off by 4 inches) Might be for naught if i dont like the Dynaudio as others have been stating.
                              This is where I believe that my description was off base, or easily misinterpreted in the original. The distance from the bottom doesn't matter, the important distances, were from the top. I specifically mentioned 1" from the top of the baffle to the edge of the tweeter frame. (so about 3" from the top of the baffle, to the center of the tweeter dome as a result). following, a midbass, about 1/2" frame to frame gap below that.

                              Sorry about the confusion.

                              The "nearest" boundaries always take precedent in these cases. The distance from the bottom, was intended to be portrayed as the least important, While the distance from the most immediate boundaries, were intended to be portrayed as the most important.

                              Best regards,
                              Eric
                              Pro/Fi Cinema Speaker project: "From the Ashes"

                              Comment

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