DIY Spinorama Jig
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Anyone know of any DIY Spinorama jig plans? I have thought of an idea of how to make one, but I wanted to see first if anyone has worked out any of the kinks first.
Basically, I am wanting to build a jig that I can put the speaker on, take a measurement, turn it 10 degrees, take a measurements, etc all the way to 90 degrees. That way I can give good polar responses out.
I know I have seen a few, but I can’t think of where.
My plan was to create a heavy duty lazy susan with the front cut off, so I can stick the speaker on the edge without the lazy susan affecting the measurements. Then CNCing that out with a Vcarve every 10 degrees. The bottom piece that it spins on would have a spring loaded stop that I can easily pull up to rotate teh degrees. At least that is my current thought process.
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When you think about it, the speaker should be rotated about the main vertical axis, and the combined Z axis, in order to keep the alignment as close as possible to the same distance from the mic. Therefore, a short front with a larger arc in the rear where the 10 degree notches can be placed, along with the latch to lock into those notches. I would do a foot activated latch, just a “L” you can step on to unlock. That’d save the back from excessive bending.
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That is an interesting idea. I like that.vI also thought about just turning the volume knob up a little until it matched. That wouldn’t be too hard. The amount of volume adjusted shouldn’t really affect the response.
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Now that I think about it, wouldn’t it be easier to rotate the mic on it’s own degree arm? Maybe something like below.
Click description for main dimensions.Make it as a sandwich, with the pivot between you could then put some felt on the top and bottom of the arcs, and thin plastic on the arm for ease of movement.plus, a 1/2 sheet of ply or MDF would be all that’s needed as you could cut all pieces, even spacers, from that one sheet.
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This is the reason forums are so powerful! You’re absolutely right. It would be easier to just move the mic. It would be nice to table to allow the mics to be extended closer or further from the speaker. That way, depending on the size of the speaker, you could move it closer to remove more room reflections, if making measurements indoors.
I think I’m gonna try to make something up in the next week or two based off of your design. See if there’s anything that were missing or forgetting.
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Those 4 holes near the plunger are for some sort of mount – I envision a locking articulating arm for the mic, so it can go forward, backward, up, down, all in a straight line. They are just placeholders. The notches are 3/4″ wide, 1″ deep, with centers on the degrees marked. I figured the plunger could be a 3/4″ dowel with the last inch sanded down just enough to fit snugly.
I could do a lot more, get the Thickness set up, do the bottom piece, move the arm so it can be cut out, etc.
I have this in CAD as 2D for the moment. To Scale, 1″=1″ Not sure what type of file you can use. DXF? STL? EPS?
“”Edit- I just saw the 90 degree requirement. I could add the rest in and redo that.
Question – if you were to cut a 1/2 sheet on your CNC, cutting out the basic 24×36 shape, what would be left over? 23-1/2″? 23″? Just trying to get an idea for the bottom half of the “sandwich”.
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Have you thought about this any more? I have.
Taking into account all your previous requirements and thoughts on how things can be done, I have mentally designed an alternative to the semi-disc out front, and placing a disc underneath in the back with the V cuts on degree. Then, still using a long arm with the pivot at the front, like above, using a long dowel or similar with ramp cut /stop on the underside that a steel ball or marble.could ride in to protrude up into the V to hold the arm steady. Then, if you would need it, you could have a small semi-circle support out front, not solid, but open like a cheap student protractor, to give some additional support to the mic end of the arm. I don’t have time to sketch anytime up at the moment, so.i hope this is explanatory enough to get the idea across.
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I was working on a different version that would use the V-Carve. It was originally going to be an arc underneath, behind the pivot point, but I soon realized that the length of the arm both ahead and behind the pivot would weaken the platform that the speaker would rest upon. SO I reduced the arc out front to make the reflective area much less, and even cut out a semi circle inside to reduce the reflections even more. That semicircle and slight lip past the pivot point are where the V-cuts will be, all part of the actual top cover / speaker base. I got about 3/4 of the way through the arm before I had to stop designing for that session. I like the looks and style of this one a lot better.
The hard part is designing the mechanism. Vision and theory is all there. getting all the details just right, well, that’s the thing isn’t it. Good thing the materials (wood) isn’t that expensive.
You know, if the V-cut system doesn’t work out, a similar system to the first would work quite well, especially if you were to go with a slightly smaller dowel and cuts to accommodate the smaller radius.
After I get the Top views finished, then generic Side views and then onto the articulating arm.**Yeah, my Dad was a mechanical drafting teacher who also worked summers in a local machine shop drafting design plans. Always had this stuff around, plus I draft Civil plans , etc. in my job. I guess it is in my nature.
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That is another good idea. I am also working on a design. I am not sure exactly how it will work, but I am excited about it. Very similar to what you are doing. I do like the idea of moving the microphone and not the speaker, since the speaker is so heavy.
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This is my secondary thought. I like the looks of this one a bit better.
The main body from the 90° mark is 24″ x 24″, with lots of support underneath, yet enough room for the boom to turn freely from lock to lock (180°). The Diamond shapes would be on the bottom side to enable the locking of the boom at those points. I am evaluating whether it would be better to use something like this with a steel ball on a ramp system, or a plunger type of system with something like a 3/8″ dowel (up/down) plunger attached to a pivot/link, and if that would be the case, then a hole would be better than the diamond shape.
As you can see, the arc area is like the type of protractor you’d have used in school – open in the middle. Less reflective surface to deal with.
Choices, choices.
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I think I am going to simplify it, by using this remote control turntable: https://amzn.to/3u5AWja The button at the bottom as a 1 degree of rotation. I am thinking of making a macro with my Sofabaton remote control to press it 10 times for 10 degrees. That way I only need one push of the button to go 10 degrees. I am sure I’ll make a custom top that allows me to have a lip to line up the speaker. Thoughts?
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That is a really good use of an existing product. You can keep the mic stand separate and static for the tests, eliminating any chance of misalignment in that way.
My thoughts on setup are quite simple. Pick your 0 (zero) point on the turn table and paint 2 lines all the way across and down the sides, at 90 degrees. Then, in your test area, paint similar 90 degree lines on the floor, with the line that the mic would sit on being extended out an extra 3-4 or so feet from the edge of the turn table (for that 1 meter SPL check) and that’s it. Square up the turntable on the lines and setup the mic as normal and away you go.
You still might need a platform for on top of the turn table, maybe with some casters off the backside because you want the pivot of the speaker face to be at the center of the turn table, but that should be an easy adapter to make.
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I went ahead and ordered it and received it today. I put a Dayton Audio speaker stand on top. So far with bookshelf speakers it works really well. I will need to test it with some heavier speakers. I have a few builds coming up that should test that. I do want/need to design something that the bigger speakers will sit on. But for now, it appears it will work. I still have a lot more testing to do.
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@TVOR-Ceasar just trying to make a jig that sits on top to make sure the speaker is always in the center. I am thinking just a cheap 3d Printed part would work well.
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You could probably 3d print a skeleton platform with at least 2 rollers or wheels hanging off the back so the larger speakers can sit comfortably secure on top, just by weight. I’d go with 3, one on each corner and on in the middle of the back line. Probably have at least 3 “pins” or tabs that fit into holes in the top of the turntable.
What do you think would be a good size? 18″ x 15″? 18″ x 18″? Bigger/deeper?
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I am thinking 3d printing a part is the best way to go. But more so just to line up the speaker stand. At least for now. That way I keep it directly center. Assuming that works, then I can later transfer that design to the cnc to make a more robust one. or a different top for the speaker stand if this is working well. I am most concerned with tower speakers. But I might just have to deal with some reflection off the turntable for towers.
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