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Build Log. Compact Home Cinema Speakers and Sub. Semi-Pro-Fi. "From The Ashes"

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  • Build Log. Compact Home Cinema Speakers and Sub. Semi-Pro-Fi. "From The Ashes"

    Hello TechTalk!

    Due to natural disaster I have the "opportunity" (excuse) to build an all new HT system. I wanted to share the project with PE-TT because I am a long time PE customer and would like others to be able to repeat this for personal use if it turns out as well as planned.

    The plan is a "basic" 5.1 system.

    Goal for the main and surround speakers is a compact direct radiator bookshelf speaker able to play reference levels at the listening position from any single speaker in the system (~105dB) without the need of esoteric dedicated amp separates. The plan is to do a complete build using manufacture supplied data, then eventually measure the completed speakers to see how close the simulation is to reality.

    I am using the Celestion TF0818 8" midbass driver, the Vifa DX25 1" dome tweeter, and a UM10-22 for the subwoofer. Amplification will be from a Denon 3313CI and Crown XLS1000 for the sub.
    Click image for larger version

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    The bookshelf speakers are 10" W x 14" H x 12" D. I am building them from chinese 23/32" "cabinet grade" 10-ply pine. At $38 per 4x8' sheet I couldn't convince myself to go with something more extravagant. For the money this stuff seems very nice, voids are few and far between (not enough for me to be concerned about it).
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    This project has a lot of things incorporated I have never done before:
    • Plywood construction! (only ever done unfinished MDF boxes in the past)
    • Nearly all-glue construction (no wood screws or visible fasteners holding the box together).
    • The front baffle will be drawn on to to the front of the box from the inside (reach in from the back of the box) using machines screws. Threaded inserts will be installed in blind holes on the rear of the front baffle to accomplish this. The front baffle will be removable for service or changes. The only visible fasteners on the front of the box will be those holding the drivers onto the baffle.
    • The rear baffle is "drawn in" to a rear pocket of the cab for aesthetic reasons, and will also be held in place with machine screws and threaded inserts.
    • I am excited to have a nice wood grain speaker. I intend to sand/stain/seal them at a later date.



    The TF0818 will be asked to dig to ~80hz. A 3" precision port will be basically glued flare-to-flare to achieve this. Port will be mounted on the back.
    Hornresp was used to simulate the low frequency range with the flared port:
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    HornResp was also used to simulate the low range impedance.

    SPLtrace was used to produce frd and zma files from the manufacture supplied data.

    "Edge" was used to simulate the effects of the baffle at the design-axis response. The uncorrected simulation was exported and converted to a useful frd for crossover simulation.

    "Boxsim" was used to simulate the driver minimum phase for each driver.

    LibreOffice Calc was used for a lot of the manipulation and splicing of the files generated by these various programs that is required to get them into a standard frd and zma files for crossover simulation.

    Speakerworkshop was used to "compile" all of the data produced above, and simulate a crossover.....
    Pro/Fi Cinema Speaker project: "From the Ashes"

  • #2
    Re: Build Log. Compact Home Cinema Speakers and Sub. Semi-Pro-Fi. "From The Ashes"

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    (I just noticed after posting this that there is a pad on version B. This was just thrown in for the sake of "seeing" the effects on response/impedance/impedance-phase. I am going run them both without any padding on the tweeter first and try that out)

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    The crossover provides a partial BSC (~3dB) for a starting point. Simulating the effects of having an extended baffle (the TV and entertainment center) between the speakers suggests that this is a good starting point to play with for the front speakers. Ignore the response in the simulation below ~200hz, it won't actually dip that far down. I included the losses caused by the rear port mount position (the differential in distance to the listener causes a partial destructive coupling effect). The intended position of these speakers will put the output from the port well into boundary reinforcement territory, so the losses shown in that simulation are not going to be realistic when placed within a foot or 2 of a wall.

    Version "A" and "B" are slight alterations in the crossover to shift phase to accommodate for different design axis. Version "B" is intended to be listened to off axis (vertically), so the same crossover is used in the rear channel speakers (since I do not know what the final placement of those speakers will be in the future, sticking to the same 3dB of BSC for the rears is a good plan for now, the removable rear baffle will make future crossover changes pretty easy.



    I have all of the box parts cut out, but have only routed and assembled the "inner" box of the 1 speaker so far. Of interesting note: with the exception of 2 cross cuts per 4x8 sheet at the hardware store, ALL of the cuts were performed with a ryobi 5.5" cordLESS circular saw, from a single charge of one of their full height li-ion packs. We have also been using this saw to build a shed out where there is no access to power (yet) and it has handled that pretty well (cutting LOTs of 2x4 dimensional lumber, and sizing up sheets of OSB). Cordless has come a long way! I'm also using a ryobi cordless jigsaw for some of the rougher internal cuts (the non-visible baffle cutouts and the internal brace were cut with the jig)... IMO I think the convenience of loosing the cord and being able to run a tool without constantly hanging up on everything is worth what is now a small enough trade in power that it is not a consequence. The jig runs as strong as any entry level mediocre plug-in type IMO which is impressive.

    Hopefully I'll have time to build some crossovers and get some more cabs built this week but we have a lot to do otherwise so this may be a few weeks in the making.

    That's all for now!

    Eric
    Last edited by mdocod; 08-27-2013, 12:59 AM.
    Pro/Fi Cinema Speaker project: "From the Ashes"

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    • #3
      Re: Build Log. Compact Home Cinema Speakers and Sub. Semi-Pro-Fi. "From The Ashes"

      Looks like a really nice project. 80 hz will be right at the limit of what those can do, but that's what the Ultimax is for. Can't wait to ser the rest of the build.
      Loren Jones

      http://techtalk.parts-express.com/sh...-sound-drivers

      http://techtalk.parts-express.com/sh...for-live-sound

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      • #4
        Re: Build Log. Compact Home Cinema Speakers and Sub. Semi-Pro-Fi. "From The Ashes"

        I used those in a simulation, with a waveuided CD, and that's pretty much the way they were tuned, short 3" port, 80Hz f3

        रेतुर्न तो थे स्रोत
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        in war, victory . . . in peace, vigilance . . . in death, sacrifice.

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        • #5
          Re: Build Log. Compact Home Cinema Speakers and Sub. Semi-Pro-Fi. "From The Ashes"

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          Well they are starting to look like speakers anyway.
          Pro/Fi Cinema Speaker project: "From the Ashes"

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          • #6
            Re: Build Log. Compact Home Cinema Speakers and Sub. Semi-Pro-Fi. "From The Ashes"

            Originally posted by mdocod View Post
            [ATTACH=CONFIG]39431[/ATTACH]

            Well they are starting to look like speakers anyway.
            Very nice

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            • #7
              Re: Build Log. Compact Home Cinema Speakers and Sub. Semi-Pro-Fi. "From The Ashes"

              Interesting. So you're going to leave these with a natural finish, even with ehh... booty-joints (as opposed to mitered)? Curious to see how that turns out. I've considered doing something like that too for a particular build, but it has hardwood baffles.

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              • #8
                Re: Build Log. Compact Home Cinema Speakers and Sub. Semi-Pro-Fi. "From The Ashes"

                Slapped some guts into them tonight so I could start to have a listen to a pair of them. By no means "done" but usable at this point...

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                Note to self: get a selection of more wire nut sizes!!!

                I won't really be able to have a meaningful listen till morning but at least they are hooked up and ready now.

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

                Hi SirNickity,

                I honestly haven't set anything in stone for the finish. I am leaning towards a dark stain front baffle and a cabernet for the sides/top. Maybe I'll stain the visible joint edges the same as the dark front for character...

                I went with the rabbet joint construction because it's all I felt I had the skill/tooling to pull off at this time. The few things I have built in my life with miter joints have never actually naturally drawn themselves up square. Though that may be different now that I have a router table. I've been researching joint bit kits for the router ;) Some day!
                Pro/Fi Cinema Speaker project: "From the Ashes"

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                • #9
                  Re: Build Log. Compact Home Cinema Speakers and Sub. Semi-Pro-Fi. "From The Ashes"

                  I hear ya! I still end up with subtle shape changes with square joints just from clamping pressure and natural warp. Nothing a square and some wood filler can't fix, but that pretty much takes staining off the table.

                  Anyway, good luck. I'm cheering for ya on this one. Looks like a nice build, and the framing/fastening ideas are really cool.

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                  • #10
                    Re: Build Log. Compact Home Cinema Speakers and Sub. Semi-Pro-Fi. "From The Ashes"

                    I sure am glad to find that there are others out there that end up with, er....dimensionally challenged panels! My table saw seems to change its mind about measurements and angles every time i push a sheet of material thru it. I built a pair of speaker cabinets a couple of weeks ago and ended up getting my best edges yet by using my band saw, of all things. I set my band saw table at 45 degrees with a fence behind the blade. That yeilded near perfect corners for once. They didn't even need clamps to make them line up.Click image for larger version

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                    GeeDeeEmm

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                    • #11
                      Re: Build Log. Compact Home Cinema Speakers and Sub. Semi-Pro-Fi. "From The Ashes"

                      I would have to do a little Snoopy dance after a corner like that. Thumbs up man!

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                      • #12
                        Re: Build Log. Compact Home Cinema Speakers and Sub. Semi-Pro-Fi. "From The Ashes"

                        Even with the straight edge with built in clamp, and the router table to run the rabbets these boxes are STILL not precisely square. They are plenty close but yea, woodworking always makes me feel like an amateur. The flush trim bit is the only thing that makes me look like I know what I am doing.

                        ----------

                        Oh I guess I missed including this pic before..

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                        Listening to them so far they seem to work fine. I don't want to make any changes till I have the sub in place and these have had a chance to break in a bit. The suspension on these celestions is crazy stiff out of the box, that combined with a slightly lower tuning than I originally anticipated (minimum length of the precision port isn't short enough!) translates to a somewhat thin sounding bottom end. Other than the missing bottom end, and perhaps being a hair too bright in the top 2 octaves, they are quite neutral otherwise with what sounds like a very balanced mid-range presentation. They sound very similar to wearing grado headphones as far as the tonal balance through the midrange. When I get the chance (house to myself) I'll let em rip a bit.
                        Pro/Fi Cinema Speaker project: "From the Ashes"

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                        • #13
                          Re: Build Log. Compact Home Cinema Speakers and Sub. Semi-Pro-Fi. "From The Ashes"

                          Bit of a set back today. I figured I better check everything else in my order for functionality/condition before my return period is up. I pressed on the cone of the UM10 and felt/heard scraping immediately. I decided to test the UM10 free air to see if the same would happen because there have been some reviews for these that suggest there may be a quality control problem. Unfortunately, there does seem to be a problem with this driver. Lots of scraping noises. Really not looking forward to having to return a 20lb+ driver.
                          Pro/Fi Cinema Speaker project: "From the Ashes"

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                          • #14
                            Re: Build Log. Compact Home Cinema Speakers and Sub. Semi-Pro-Fi. "From The Ashes"

                            Originally posted by mdocod View Post
                            Bit of a set back today. I figured I better check everything else in my order for functionality/condition before my return period is up. I pressed on the cone of the UM10 and felt/heard scraping immediately. I decided to test the UM10 free air to see if the same would happen because there have been some reviews for these that suggest there may be a quality control problem. Unfortunately, there does seem to be a problem with this driver. Lots of scraping noises. Really not looking forward to having to return a 20lb+ driver.
                            PE is awesome with returns, I would call them and they may take care of the rest.
                            If we all reacted the same way, we'd be predictable, and there's always more than one way to view a situation.
                            What's true for the group is also true for the individual. It's simple: Overspecialize, and you breed in weakness.
                            It's slow death.

                            //Burn n' Die//Dream Weaver//Maximus//ABC Bookshelf Speakers//Dayton Twin Towers

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                            • #15
                              Re: Build Log. Compact Home Cinema Speakers and Sub. Semi-Pro-Fi. "From The Ashes"

                              Yea I'll call them up Monday and see about getting this one swapped out. Debating now whether to try another UM10 or go with something else. I had intended to shove the UM10 into a compact tapered TL with a small compression chamber (basically enough space for the driver basket to hang into, braced up and shrunk down excessively).

                              Only ~3ft^3 internal. A compact tapered line long enough and narrow enough to provide useful response down to ~20hz.
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                              @1W1M2Pi ; Note, [email protected] from ~30-60hz. This is a very nice efficiency in this passband for a box this small. +6dB over the direct radiator sensitivity of the driver alone in a bandwidth below EBP.
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                              @1000W1M2Pi
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                              Driver displacement is very well managed and should not need any additional high pass other than the natural ~20hz high pass in the XLS1000. Note that while response tapers off below 30hz in this design, it is technically "loaded" to below 25hz and still has enough acoustic impedance below that to do 20hz. The narrow line combined with the slightly weaker motor of the UM10 (compared to other driver options for this build) provides good displacement control below the last resonance of the line. (shallower rise)
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                              "maximum" SPL:
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                              ----------------------

                              I don't have any more pictures to add as it would just be more of the same. I'm grinding through the other 3 (center and surrounds) this weekend and think I might have them installed in an unfinished state by tomorrow night.
                              Pro/Fi Cinema Speaker project: "From the Ashes"

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