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Classix 2.5 Cabinet

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  • Classix 2.5 Cabinet

    Hello again.
    My parts arrived for the Classix build. Thanks everyone for the help earlier this month.

    I am getting ready to start building the Cabs but I have a few questions before I start.

    First off,... I am 6'4" tall with bad knees so my furniture is rather tall (Sitting on blocks). Also the position of the speakers in room will be approximately four feet from the end of two coutches that run along the sidewalls of my living room.

    This puts me in a bit of a conundrum. The cabs are to be 34" tall if I stick with Pauls suggested cab design. I have measured and that puts the tweeter WELL below my ear level and very close to below the arms of the couch's.
    So I was just going to build them with a false bottom (empty space).... and that got me to thinking.

    1... Is it possible to make the Cabinets deeper but shorter to turn them into a rather large bookshelf style, and if so... How deep can I go without significantly altering the performance, if it all??
    2....I am also wondering if it can be made deeper and shorter with a the false bottom and add a sub into both cabs.??
    Or would this be overkill since the The Classix 2.5 dig rather deep already??

    I was looking at the 8"classic Subwoofer as well as others.....

    And it looks like in a .90cubic foot cabinet tuned to 34hz with a 2.5" x 12" port mite work well... but again is it really needed? it just seems like wasted space

    I have looked at the math and I can make the upper part, with the required internal volume, 26"t x 12"d x 6.5"w giving me a volume of 1.17cf.... pretty deep I know
    Then making the bottom volume 21t x 12d x 6.5w for an internal volume of .947cf

    This would be a big speaker but I am a big man and it puts the Classix drivers in a better position for me.

    Still.... getting back to my original question, is it going to enhance low end performance or get in the way??

    I dont want to destroy the spirit of the design just to make use of space however it does have a practical use as well since the 34" height would need to be raised in one way or another any way.

    I am open to any and all thoughts and perspectives. Thanks guys.

  • #2
    Not to speak for Paul, but if you keep the baffle width the same, and maintain the same driver spacing from the top of the cabinet, then altering height/depth shouldn't be a big issue.


    • #3
      According to Paul's website, the Classix 2.5s have an F3 of 35 Hz; that would seem low enough to deal with most music, so adding a sub might not be necessary. I think you would only need the sub if you really dial up the volume on challenging source material.

      Depending on how it looks, I'd be inclined to build a slightly taller cabinet - with the drivers spaced as per Post #2 - with a false bottom. If you made them deeper and shorter, you'd be putting them on stands, which might look awkward and not be very stable.

      I'm 6'1" and would build the Classix 2.5 as per the design, on our couch that would put the tweeters at ear level.



      • #4
        (I know you've already got "Classix" parts, but ...) For a big guy (who apparently likes or would like to have big speakers) I think the "Dayton D8" would have been right up your alley. Dual 8" woofers with NO SUB required. They can best 30Hz. Even the "D-III" (dual 6-1/2"ers) or Paul's Classix MTM (or does he have a TMM/2.5 way? - I think so?) would probably meet your needs better (in a taller box).

        While Dayton's 6-1/2" woofers can go as low as they need to (for music), both those (@ 3.2mm Xmax) and the 8" (4mm Xmax) CAN bottom out when cranked as single woofer designs. They tend to have the voice coil whack the backplate at not much above their Xmax, sounding kinda like a machine guns. Still (aside from the startling sound) I've "abused" those woofers for (10-15) YEARS w/out them coming apart (or melting).


        • #5

          All this basic down and dirty talk about what works and what doesn't is just so stimulating!!


          Naughty boys.


          • #6
            Originally posted by chrisn View Post
            Not to speak for Paul, but if you keep the baffle width the same, and maintain the same driver spacing from the top of the cabinet, then altering height/depth shouldn't be a big issue.
            Chris said it so good I'm not going to run my mouth repeating it.

            Good luck with the build, and enjoy!!
            Isn't it about time we started answering rhetorical questions?

            Paul Carmody's DIY Audio Projects
            Twitter: @undefinition1


            • #7
              I can't quite visualize your seating/ speaker arrangement, but I just finished some MTM speakers for my modest home theater. I wanted them to be below the stairwell railing behind them so I put them on stands tilted back 5 degrees. They point to my listening position.

              Also, if you're going to punish your Classix 2.5s, there's nothing wrong with subwoofer(s), separate or included. Separate subs would be more flexible. They could be visually coherent with your L/R cabs so as to look like a one piece tower. With proper bass management to steer all low frequency content to the sub(s), your Classix would be less stressed. A driver wider than the Classix baffle could be side mounted.

              Just some thoughts.


              • #8
                Yep... thank you for confirming what I thought guys.... It probably isnt needed.

                I am happy I choose Paul's Classix 2.5's. They will fit my needs and music style.

                Geof Miller "According to Paul's website, the Classix 2.5s have an F3 of 35 Hz"

                I think that nix's the 8"classic sub rite there. That was a concern I noticed right off, I wanted to stick with the Classic Line so I choose that driver, but would be willing to spend a tad more on a different driver.
                I would keep the width at the required internal dimension of 6.5" so they would need to be side mounted and separately powered with some bass management DSP.
                I may keep looking, if just to satisfy my curiosity. For now.

                You know I did look at the D-8's some time ago and may still build them. I already have 4 of the 8" classic woofers and 2 silky's. Left overs from my first attempt at designing a 2 way book shelf speaker like ten years ago or so. Then i bought two more for a MTM.
                Both failed attempt's I mite add. Just couldn't get the XO right. The design lacked a lot of mid-range.
                Then I discovered that the 8' can be difficult.
                The 6.5" seems to be the driver of choice for so many design's. that is why I chose Paul's.

                I haven't given up on the Idea of a built in separate individually powered sub for each speaker but for now I am going to just explore the minima height I need to make the towers.
                Possibly rearrange some of my space as well to figure out what works better. Up until now I have only used book shelf speakers on stands I made. the height was perfect so I do have a starting point to reference.


                • #9
                  OK well that didn't take long.... Why mess with a proven design.
                  Adding a sub into the cabinet is just stupid. If I feel the need I can add a stand alone sub or two down the road but I doubt I will need to.

                  The biggest problem would be the required width of the cabinet limits the choice of drivers. in order to put one into the mix, that would go low enough to make sense, I would need a sub driver mounted on the side of the cab. One that doesn't have a large (deep) mounting depth requirement. It could be done with one of the Reference or Ultimax drivers however it would require some elaborate cabinet work.

                  Soo... I have put that idea in the round file. It was worth exploring,... it just doesn't make sense. Who am I to mess with perfection.

                  I may stretch the depth a tad just so the cab doesn't look tall and awkward. just for aesthetics really. It would give it a beefier looking depth and I can make the cabs as tall as I need them with a false bottom.

                  My couches are really high. I had to put them on taller legs raising the height about 6" in order for me to get in and out of them comfortably as both of my knees are shot. Several surgery's and arthritis have destroyed them. My wife sewed some longer skirts for them. So you cant see them. People are always asking where we got the couches. One is "L" shaped running along the left wall out into the middle of the room and the other is a matching one piece running along the right wall.

                  Moving on... I will be running some pictures out soon of the build process. and maybe some ideas on construction.

                  Thank you for indulging me.
                  Rock on!!


                  • #10
                    cjd's Ansonica.

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                    • #11

                      WOW....That is to funny.... I was just thinking about doing something like that.

                      ....Then some shot in the false bottom for some weight then build some out rigger feet.

                      I have been sketching up rough plans and that will certainly be on my short list.


                      • #12
                        I'm very happy with my low leaned back home theater setup.

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                        • #13
                          Sweet.... I like the look of those stands. Very stout. So many store bought stands are not very stable unless you spend a fortune on them.
                          DIY...The only way to fly.

                          Believe it or not I have never figured out the internal volume of a 3 dimensional Parallelogram.
                          Does the formula stay the same even though the front and back panels cut length becomes slightly longer once you introduce a degree of angle?
                          but the overall height of the speaker stays the same.

                          for example....
                          In the plans you shared with me DJG, would I use the 54" measurement or the 54.5" measurement to calculate volume?

                          I can use an online calculator but I would still like to learn.


                          • djg
                            djg commented
                            Editing a comment
                            They are actually 34" high, much like the Classix cab. The font is a bit wonky.

                        • #14
                          Never mind I figured it out....


                          • #15
                            Now I'm curious to see these couches
                            Isn't it about time we started answering rhetorical questions?

                            Paul Carmody's DIY Audio Projects
                            Twitter: @undefinition1