Announcement

Collapse
No announcement yet.

Paul Carmody's OS Center Build - I may have cocked this up...

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

  • Paul Carmody's OS Center Build - I may have cocked this up...

    Hello! First post here, new builder, having a go at this center channel and starting off on the enclosure.

    Thing is, the plans are in 1/2 inch stock, but I'm using 18mm plywood (about 3/4"), and I've just realised this might cause a problem...

    Quite apart from whether I can get the speakers into it (it does look tight, but I think it'll be okay), will it sound like a load of crap because I'm losing some of the inner volume? I used the same outer dimensions, thinking it wouldn't be a big difference, but now I'm wondering...

    I note the plans call for a 71mm recess in the back panel for the woofers, but I'm not sure why this is, as the woofers aren't this long, even if they're flush with the front panel. Which mine won't be, now. What am I missing?

    And if anyone has built one, and has pics of their crossover, would they mind posting them? I will struggle to read a circuit diagram, but I can copy a front and back pic no problem. It's my first build, so I really want to minimise the risk of it sounding terrible...

    Having said that, I've solved a few minor woodworking issues, and have found it satisfying so far.

    Very grateful for any advice!

  • #2
    It's a sealed cabinet with 4 B3Ns? If that is the case its not a deal breaker. If it was/is vented you'd have to adjust the vent length for the smaller size.

    Comment


    • #3
      Thanks Chris. Yes, cabinet is sealed. Glad to hear it shouldn't be a problem. Lesson learned - should have added 1/2" to outside dimensions. Heigh-ho.

      If anyone has any details of crossover, I'd be glad to see them. I'm thinking type of board and components used - I have a component list, but what level of parts do I need? Poly caps? Sand-cast resistors? Don't have much experience in this area.

      In terms of mounting the crossover board, I've made the rear panel removable. I should add some pics at some point, but I have small children and am doing this bit by bit in any spare time I get, and once they're asleep. Anyone with children here will feel my pain! But it's a nice little diversion. If this goes okay, I'd like to try the main OS build to go with it..

      Comment


      • #4
        Does anyone have a list of the crossover parts? What kind of inductors I'd need, for example? Not sure on gauge, mH or RDC, whether I can mix and match these at all?

        I've done a lot of looking online for pictures of built crossovers, think I'm fairly clear on resistors and capacitors, just not the inductors..

        Comment


        • #5
          Anyone?

          Comment


          • #6
            All capacitors are Poly. Resistors are 5 or 10W. The tweeter inductor is 20ga. The 1.5mH is 18ga Air Core. The 3.5H is an 18ga Steel Laminate core.

            Comment


            • Bearforce One
              Bearforce One commented
              Editing a comment
              Thank you Sam. Have you built one? How did it go?

          • #7
            Originally posted by Bearforce One View Post
            Does anyone have a list of the crossover parts? What kind of inductors I'd need, for example? Not sure on gauge, mH or RDC, whether I can mix and match these at all?

            I've done a lot of looking online for pictures of built crossovers, think I'm fairly clear on resistors and capacitors, just not the inductors..
            For the inductors, you can use air core, 18 or 19 AWG. Should be fine.
            Isn't it about time we started answering rhetorical questions?

            Paul Carmody's DIY Audio Projects
            Twitter: @undefinition1

            Comment


            • Bearforce One
              Bearforce One commented
              Editing a comment
              Thank you Paul. I'll press on and get my parts ordered.

              I have wondered whether to add depth to the cabinet, with maybe some 1" strips of ply, before I glue on the baffle, given I've used 3/4" stock. Would I be wasting my time?

              Next build, I'm eating the shipping to the UK.. (sorry, Meniscus..)

          • #8
            Update: I worked out (I think) that to allow for using 18mm ply, to get the same volume I'd need to add 33mm in depth. This sounds an awful lot for just using material 6mm thicker, but there you go. I decided to extend the front with strips of ply, and although it'd work, it looks like a dog's dinner.

            I think I'm going to redo it, either resized for 18mm ply, or as per in 12mm. But it's been a good learning curve, and I've learned a few things too. Just a few, mind!

            I'm wondering though, whether using 18mm over 12mm would make any difference to the sound quality? There are no braces in this speaker, given that it's quite narrow I assume and therefore pretty rigid by itself. Would this tell me that using thicker material would be a waste of time? Curious to know how it all works..

            Many thanks. I will put some pics up so you can all have a laugh..

            Comment


            • #9
              I ordered the kit from Meniscus in the end too, so I didn't drive myself insane trying to work out the crossover on my own

              Comment


              • #10

                Comment


                • #11
                  Best view is from behind

                  Comment


                  • #12
                    Welcome Mr Bear...

                    The most important thing is to make it airtight and get the crossover right. Then it will sound as it should, which is a big encouragement.

                    We've all been there, don't sweat it man. It doesn't look bad, but if you dare to build another in the future, it will look better... The first few are learning experiences.

                    TomZ
                    Zarbo Audio Projects Youtube Channel: https://www.youtube.com/channel/UCEZ...aFQSTl6NdOwgxQ * 320-641 Amp Review Youtube: https://youtu.be/ugjfcI5p6m0 *Veneering curves, seams, using heat-lock iron on method *Trimming veneer & tips *Curved Sides glue-up video
                    *Part 2 *Gluing multiple curved laminations of HDF

                    Comment


                    • #13
                      Thanks Tom.

                      It has been fun, but the bodge of adding those strips of ply was one step too far for me! The best bit was how nicely the back piece fitted in. Bit of a fluke maybe, but I’ll take it (I had the pieces cut instore..). And using insert nuts was a nice idea I borrowed from someone’s Speedster thread on SBAF.

                      But I think I’ll take that experience and redo it. Plywood isn’t too expensive here. I’ve worked out measurements to do in 18mm. I like the idea of a solid, heavy box. Will it make any difference to how it sounds, though??

                      Thanks again for your kind words. Just what I needed!

                      Comment


                      • #14
                        Originally posted by Bearforce One View Post
                        Thanks Tom.

                        It has been fun, but the bodge of adding those strips of ply was one step too far for me! The best bit was how nicely the back piece fitted in. Bit of a fluke maybe, but I’ll take it (I had the pieces cut instore..). And using insert nuts was a nice idea I borrowed from someone’s Speedster thread on SBAF.

                        But I think I’ll take that experience and redo it. Plywood isn’t too expensive here. I’ve worked out measurements to do in 18mm. I like the idea of a solid, heavy box. Will it make any difference to how it sounds, though??

                        Thanks again for your kind words. Just what I needed!
                        Oops, sorry, I missed your question.

                        I think slightly thicker wood panels wouldn't hurt, but rather help slightly. As long as you leave the same basic internal volume, you should be fine.

                        I used to make all of my speakers back in the day (25 years ago) with double thicknesses of 3/4" Particle board and 3/4" plywood for the outside. Way overkill. I could have just braced the cabinet in strategic areas and used one panel thickness and saved my back. I did love the feel of a super-heavy cabinet though, and if you're not going to move it much, why not I guess; but proper bracing is most important.

                        I was just blabbing there, but going with slightly thicker wood is fine, that's a small difference if you're talking about going from 1/2" to 3/4". Post some pics up, I love seeing people's first few sets of speakers. Maybe in a few years you'll be making stuff that will amaze you. My first few sets back in the 90's looked as bad as they sounded!

                        TomZ
                        Zarbo Audio Projects Youtube Channel: https://www.youtube.com/channel/UCEZ...aFQSTl6NdOwgxQ * 320-641 Amp Review Youtube: https://youtu.be/ugjfcI5p6m0 *Veneering curves, seams, using heat-lock iron on method *Trimming veneer & tips *Curved Sides glue-up video
                        *Part 2 *Gluing multiple curved laminations of HDF

                        Comment


                        • #15
                          Couple of pics here. One is the straightest cut I could get by hand, with a tenon saw. But I wanted it to be square, so I found a local joiner and offered him biscuits to make some cuts for me.

                          So I’ve started again, resizing for 18mm ply. If the back piece of this one fits in as well as the last, I’ll be happy. The rest, I can either tidy up or live with.

                          It really isn’t possible to cut dead straight by hand, is it?

                          Comment

                          Working...
                          X