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Two-Way Version 2 build thread

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  • DeZZar
    replied
    For the finish on these versions all corners are rounded - top, bottom, sides and corners - and the intention is that they would be wrapped in "leather". Before committing to this I wanted to make sure it was possible (as in possible for me and to a high standard) so I made a small version to test it out.

    36mm round over for front edges and 25mm for the sides. The side panels are just screwed on to start with so they can be separated.
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    Next the sides are removed and the joined edges receive a small recess to cater for the thickness of the leather.

    You can see the final gap here
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    Having covered things in "leather" before I knew that corners tend to be the hardest part and you need space for inevitable "bunching up" of the material, so I used a dovetail router bit to cut a gutter in the back edge:
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  • DeZZar
    replied
    Cabinet gluing up. In this design the sides have to be glued on last so here just gluing the tops and bottoms to the rear panel.

    I used several dowels to strengthen the joints here and help with alignment when clamping.
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    The small rear enclosure for the crossover added as well.
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    Baffles prepared and here making the cutouts and recess for the drivers. (yes that's a home made circle cutting jig if anyone's wondering)
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    Cutouts finished and a chamfer added to the rear for the woofer.
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  • DeZZar
    replied
    The CNC cut rippled panel. There is a bit extra in here for another project - was obviously just more economical to get it all cut at the same time.
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    Ready for glue up. This is the section that forms both the bottom surface of the cabinet that the woofer sees as well as the wall for the slot port.
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    In the previous version I found there were some obvious standings waves corresponding to cabinet height seen particularly in the port measurements. So this time around I wanted to see if I could improve on these by first curving the bend in the port as well as better treating the bottom surface of the cabinet.

    These curved sections were rather painful to make but they make sure the port follows a proper radius as it bends towards the exit.
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    Last edited by DeZZar; 05-24-2021, 02:03 AM.

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  • DeZZar
    started a topic Two-Way Version 2 build thread

    Two-Way Version 2 build thread

    Hi All,

    Thought I would start a build thread to share my current project. I'm working on a second iteration of a design I started last year which I had jokingly called the "Quick Two Way" thinking I would just throw together a two way design during one of our countries COVID lock-downs to keep me occupied.

    There ended up being nothing quick about it of course but I was seriously impressed with the results and instead of moving on to another planned project I really wanted to try another version with an improved cabinet design and bass alignment.

    The original project I posted here for feedback some time ago:
    http://techtalk.parts-express.com/fo...two-way-design

    In the second version of this I wanted to:
    • Reduce the cabinet size to something more reasonable for a two-way floor standing design
    • Change the alignment a little and ultimately correct an issue where the tuning of the original cabinet ended up being a lot lower than modelled (which I couldn't do anything about after the fact)
    • Experiment with some internal sound energy dissipation ideas
    • Change the aesthetic design

    This design uses the Dayton RS180P-4 7" woofer and the SB Acoustics SB29RDAC-C000-4 tweeter with a 1,750Hz crossover point.

    So I finally pulled the trigger and have started the new build. Here is the revised design
    Click image for larger version  Name:	Design.PNG Views:	5 Size:	421.0 KB ID:	1470084

    Cabinet has been reduced to a net effective internal volume of 26L vs the original 32L and tuning moved to 39Hz. This will produce f3 around the 36-37 Hz range.

    The offset rippled interior. I have no proof that this does anything meaningful - its an idea I had years ago and never really had the chance to execute on it. I thought it might be a pointless idea until I happened to stumble upon one other commercial example of this which motivated me to try it out.

    The theory is simple - remove the possibility of any directly reflective surface - in this case particularly with respect to the waves directly behind the drivers - using a pattern that should in theory scatter the sound waves and use up more of their energy before they have a chance to interact with the driver again.

    I hypothesize that any legitimate improvement here would be seen in the areas affected by standing waves and in distortion measurements. I still have the first versions with me so I'll be able to make comparative measurements.

    Before anyone asks, there is no science to the shape and size of the ripples. I just drew up what I thought was reasonable and sent them off to my CNC guy to be cut.

    Sheet stock cut down into the panels. This is a layered construction so starting with 12mm (1/2 inch) MDF.
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    Internal braces cut
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    Just testing the layout and thinking about which way to go about the glue up.
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