Announcement

Collapse
No announcement yet.

Build thread: Psalms tower speakers

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Build thread: Psalms tower speakers

    Hi, all. This thread will document the process of building a pair of Rick Craig-designed tower speakers. These might be some of the last speakers he ever designed. I worked with Rick last spring and summer (2021). I'm sure many of you know of Rick. He was truly one of the great guys in the world of speaker design. I thoroughly enjoyed working with him on this design; I was really saddened to learn of his untimely death. The design was finished late July last year, but due to a protracted medical crisis with my mom, I hadn't been able to start the build until recently. I had, however, been accumulating the necessary parts/raw materials in the interim. Rick and I never settled on a name, but ruminating recently I thought I'd call them the Psalms Towers, as a nod to Rick's company, Selah Audio. He also designed a matching center channel - but that will be a separate project.

    While this is my first ever speaker build, I am no stranger to woodworking or machining. Rick and I agreed that he would design a basic rectangular cabinet, and I would use the baffle dimensions and interior volumes to design a slightly more elaborate cabinet. My 3D CAD skills are...developing; so I did all the design work in 2D CAD with a fairly elaborate Excel spreadsheet to help out with all the necessary calculations. Though I am pretty handy with a soldering iron, Rick built the crossovers and shipped them complete to me last summer.

    I will likely have some questions along the way, but I've done a lot of research and even more thinking about this project for a long time. I'll probably over-document things - hopefully folks don't mind a lot of pictures.

    The drivers will be:
    T: 1" Bliesma T25B-6 beryllium dome
    M: 5" Satori MW13TX-8 with TeXtreme cone
    W (x2): 6.5" Purifi PTT6.5X08-NFA-01 with the funky surround

    The cabinets will be made with 3/4" maple Appleply (more on that later), which I special ordered from a supplier here locally. This stuff is HEAVY. Much more dense than Baltic birch. The curved sides will be 3 layers of bent-laminated 1/4" Baltic birch. That process will be a challenge unto itself -- 1/4" Baltic birch doesn't like to bend.

    My hope is to get these to a point where I can spray them while it is still warm enough to do so. I plan on using automotive polyurethane clearcoat - the same as I used to paint my truck. I've done tables and other projects with it in the past and the results are spectacular.

    Anyway, I hope you come along with me on this journey. And I hope to do Rick proud.

  • #2
    Just for fun I did a comparo of Applyply to the other two types of plywood commonly found in woodworking shops.

    Click image for larger version

Name:	plywood comparo.jpg
Views:	1
Size:	33.8 KB
ID:	866872

    Comment


    • #3
      Here is the pile of goodies. Hopefully these will come together to make something good. This includes the drivers I'll use in the center channel, too.

      Click image for larger version

Name:	IMG_3124.jpg
Views:	1
Size:	99.7 KB
ID:	866875

      And a stack of money represented by wood product. This is more than I need for this project to be sure. And it doesn't show the 1/4" Baltic birch I'll be using for the sides.

      Click image for larger version

Name:	DSC_6930.jpg
Views:	1
Size:	71.7 KB
ID:	866873

      Comment


      • #4
        Looking forward to watching this evolve.

        I've always had regard for Rick, seemed a very decent guy. How amazing is it that he managed to design a speaker without actually building any cabinets!?

        Or did he build them with the drivers on hand, then you buy drivers from him and build your own lovely cabinets? Or are you using your own drivers, true to DIY form?

        Probably the last 3 way Rick designed. Congrats

        Comment


        • #5
          This looks like a fun project. Tell us about the crossover you will be using.
          Michael
          Chesapeake Va.

          Comment


          • #6
            You look like you’re setup to have a very interesting time building these, and have some very nice speakers to listen to when it’s all finished.

            Very nice choices on the drivers. We’ve talked about some similar configurations for Steve Manning, mainly just differing in the choice of midrange driver. The Saatori motor should give you excellent midrange distortion performance.

            And I can relate to your choices of construction material- I just received several pieces of 1-1/4” thick maple ply, fabricated for use as piano pin blocks, but which makes excellent front or rear baffle material.

            By all means, pictures tell the story very well, so we look forward to seeing your build story as it unfolds .
            the AudioWorx
            Arvo Pärt
            Isiris MLBL
            Modula MT
            Natalie P
            M8ta
            Modula Neo D CC
            Ardent
            Modula MT XE
            Modula Xtreme
            Isiris
            Wavecor Ardent

            SMJ
            Minerva Monitor
            Calliope
            Ardent D

            In Development...
            Isiris Mk II updates
            Calliope CC
            Obi-Wan
            Saint-Saëns Symphonique
            Modula PWB
            Calliope CC Supreme


            Resistance is not futile, it is Volts divided by Amperes...
            Just ask Mr. Ohm....

            Comment


            • #7
              The 1-1/4" pin block maple ply as used in the Kurosawa cabinet builds proved most satisfactory...


              DFAL
              Dark Force Acoustic Labs

              A wholly owned subsidiary of Palpatine Heavy Industries

              Comment


              • #8
                Originally posted by bimmerguy View Post
                Hi, all. This thread will document the process of building a pair of Rick Craig-designed tower speakers. These might be some of the last speakers he ever designed. I worked with Rick last spring and summer (2021). I'm sure many of you know of Rick. He was truly one of the great guys in the world of speaker design. I thoroughly enjoyed working with him on this design; I was really saddened to learn of his untimely death. The design was finished late July last year, but due to a protracted medical crisis with my mom, I hadn't been able to start the build until recently. I had, however, been accumulating the necessary parts/raw materials in the interim. Rick and I never settled on a name, but ruminating recently I thought I'd call them the Psalms Towers, as a nod to Rick's company, Selah Audio. He also designed a matching center channel - but that will be a separate project.

                While this is my first ever speaker build, I am no stranger to woodworking or machining. Rick and I agreed that he would design a basic rectangular cabinet, and I would use the baffle dimensions and interior volumes to design a slightly more elaborate cabinet. My 3D CAD skills are...developing; so I did all the design work in 2D CAD with a fairly elaborate Excel spreadsheet to help out with all the necessary calculations. Though I am pretty handy with a soldering iron, Rick built the crossovers and shipped them complete to me last summer.

                I will likely have some questions along the way, but I've done a lot of research and even more thinking about this project for a long time. I'll probably over-document things - hopefully folks don't mind a lot of pictures.

                The drivers will be:
                T: 1" Bliesma T25B-6 beryllium dome
                M: 5" Satori MW13TX-8 with TeXtreme cone
                W (x2): 6.5" Purifi PTT6.5X08-NFA-01 with the funky surround

                The cabinets will be made with 3/4" maple Appleply (more on that later), which I special ordered from a supplier here locally. This stuff is HEAVY. Much more dense than Baltic birch. The curved sides will be 3 layers of bent-laminated 1/4" Baltic birch. That process will be a challenge unto itself -- 1/4" Baltic birch doesn't like to bend.

                My hope is to get these to a point where I can spray them while it is still warm enough to do so. I plan on using automotive polyurethane clearcoat - the same as I used to paint my truck. I've done tables and other projects with it in the past and the results are spectacular.

                Anyway, I hope you come along with me on this journey. And I hope to do Rick proud.
                Looking forward to many photos and your journey of building the Psalm towers.
                Painter in training

                Comment


                • #9
                  My goodness the workshop area you've got is huge!
                  What you screamin' for, every five minutes there's a bomb or something. I'm leavin' Bzzzzzzz!
                  5th Element, otherwise known as Matt.
                  Now with website. www.5een.co.uk Still under construction.

                  Comment


                  • #10
                    @tktran: While Rick didn't build a bespoke cabinet for my speakers, he did fit the drivers to different test boxes he had wherein he could test the drivers' performance with various volumes and baffle widths.

                    @1Michael: I am a bit embarrassed to say I can't speak very intelligently about the crossovers...yet. Rick designed and built them; I plan on sitting down with them and diagramming them out electrically, but the desire to make saw dust is strong and I haven't prioritized it yet. But your suggestion might be the prodding I need to do so. It's been quite a long time since I taught undergraduate electronics labs when I was a grad student. It will be fun to diagram circuits again.

                    @JonMarch & Evil Twin: I've seen that piano pin block. It's mighty cool stuff indeed. I had actually toyed with the idea of using it for the baffles, but when running through the construction process in my head, I thought that using a piece of 3/4" & 1/2 Appleply laminated together would do the trick. So that's where I landed. I would like to get some of that pin block some day just to have it -- maybe use it for my future sub build.

                    @5th element: What you see in the pictures is approximately half of the shop. I have a Spancrete garage floor, which means there is a room under the garage with exactly the same square footage as the garage above. There is a driveway that runs from my main driveway down to the shop entrance. The Spancrete beams are 12" thick. It's a 4-car garage, but extra deep at about 35 feet, and about 44 feet wide. The overall square footage is about 1350 give or take since it is not a perfect rectangle. The shop is attached to and accessible from inside the house since it is under the garage, but has its own independent HVAC system. I designed and built my house back when I was but a youth in 2004, but I think if I had to do it over again I would build a separate outbuilding for the shop so I'd have more space.

                    Comment


                    • #11
                      I'd mentioned that the sides of the speakers will be curved. I am not a CAD genius, but here is a 2D drawing of what it will look like shape-wise.

                      Click image for larger version

Name:	Capture.jpg
Views:	1
Size:	12.2 KB
ID:	866886

                      I started by making some templates in some thin sheet stock using one of my homemade router compasses.

                      Click image for larger version

Name:	IMG_3519.jpg
Views:	1
Size:	120.0 KB
ID:	866887
                      Click image for larger version

Name:	IMG_3521.jpg
Views:	1
Size:	117.9 KB
ID:	866888

                      I would like to make the curved sides out of 3 laminated pieces of 1/4" Baltic birch plywood because it's very stiff and I've never seen anyone do that before (I'm sure it's out there but I haven't seen it myself). Also, 1/8" MDF, which seems the more traditional/common way to make bent panels, is not available at the big box stores near me (I'd have to go to a specialty supplier like I did for the Appleply); but the 1/4" Baltic birch is readily available in 4x8 sheets at Menards, and in Minnesota you can't swing a cat without hitting a Menards. But bending 3 sheets of Baltic birch is going to present a considerable challenge.

                      Which brings me to experiment #1: Using my vacuum press to force the plywood to my will. I made a form out of some manky white oak, an old piece of 1/4 plywood, and half a sheet of 1-1/2" rigid insulation.

                      Here's the vacuum press I built years ago:
                      Click image for larger version

Name:	05.jpg
Views:	1
Size:	56.9 KB
ID:	866889

                      And I'll spare you the gory details of building the form and just skip to the still photo equivalent of the 1980s video montage...
                      Click image for larger version

Name:	form.jpg
Views:	1
Size:	112.8 KB
ID:	866890

                      The form turned out great. I covered it with clear tape to prevent glue from sticking to it. I was confident it would work like a champ. I tried it first with a single piece of plywood. I could barely bend the plywood with all my weight, but the weight of air proved heavier! Alas, the vacuum bag always sucked in under the edges of the panel no matter what I did, which would change the radius slightly. Trying two pieces together made it even worse - it would suck in earlier in the pump-down and pull in farther. Sigh. After all that work I had to abandon that idea. Maybe I'll use the form again...if I ever happen to have another project that requires the exact same radius...and length....and width. Sigh again. At least it looks pretty sitting there in the corner of the shop.

                      But it's not all bad. With every project I look for an excuse to buy another tool, and this was it. And this tool was from across the pond. More on that in the future.

                      Comment


                      • #12
                        While I waited my new tool to arrive, I set about breaking down the rest of the sheet goods using my track saw.

                        Click image for larger version

Name:	IMG_3554.jpg
Views:	1
Size:	113.5 KB
ID:	866891

                        I'm a little persnickety about tolerances.

                        Click image for larger version

Name:	IMG_3559.jpg
Views:	1
Size:	35.5 KB
ID:	866892

                        Click image for larger version

Name:	IMG_3555.jpg
Views:	1
Size:	90.7 KB
ID:	866893

                        Click image for larger version

Name:	IMG_3556.jpg
Views:	1
Size:	66.3 KB
ID:	866894

                        It doesn't seem like that much when you stack it all together.
                        Click image for larger version

Name:	IMG_3561.jpg
Views:	1
Size:	72.2 KB
ID:	866895

                        Comment


                        • #13
                          I’d say that you’re well prepared to have a good time getting these speakers built, and we will definitely enjoy watching you do it with all the pictures you’re providing- you know the old saying, a picture is worth a thousand words… especially if it’s captioned well!
                          the AudioWorx
                          Arvo Pärt
                          Isiris MLBL
                          Modula MT
                          Natalie P
                          M8ta
                          Modula Neo D CC
                          Ardent
                          Modula MT XE
                          Modula Xtreme
                          Isiris
                          Wavecor Ardent

                          SMJ
                          Minerva Monitor
                          Calliope
                          Ardent D

                          In Development...
                          Isiris Mk II updates
                          Calliope CC
                          Obi-Wan
                          Saint-Saëns Symphonique
                          Modula PWB
                          Calliope CC Supreme


                          Resistance is not futile, it is Volts divided by Amperes...
                          Just ask Mr. Ohm....

                          Comment


                          • #14
                            You beat me to it Matt ...... that's a nice shop!

                            FYI on the ApplePly, they make it up to 1.5" thick. I've been looking at it for a replacement to Baltic Birch since it's next to impossible to source these days.
                            Hold on to your butts - It's about to get Musical!



                            WEBSITE: http://www.smjaudio.com/

                            Comment


                            • #15
                              I built a 24CBT curved line array recently, and used 1/4 BB doubled up for 1/2 inch total for the baffle. I first cut the radius I wanted on the 2 side pieces, then clamped down the 2 thickness of the baffle onto the sides, with glue only between the 2 baffle pieces.. When it dried, it was about 1/2 of the curve I needed, but that made it easy to glue the 1/2 inch "sort of curved" baffle onto the sides. I'll see if I have any pictures. You could always build another fixture and steam the 1/4 BB, that would make it easy to bend.

                              Comment

                              Working...
                              X