DIY spinorama turntables

[TasTinker]

With discussion in various development threads on DIY spin turntables I'm picking up on Rick Sykoras suggestion and starting a thread for DIY turntable build ideas.
Most use one of the various furniture dolly offerings. Here's a different approach I took using a bolt on front wheel bearing assembly from a car. Obviously not for everyone but has the advantage of greater overhang strength, especially when doing vertical spins with floostanders hanging out to one side.

 

[TimVG]

 

[mtg90]

Here are mine:

That one uses a 20" lazy Susan bearing in a recess routed between the two discs which works well, very stable with almost no play and spins extremely smooth:

The bigger one (36" diameter, 10ft tall) uses a smaller 12" lazy susan bearing in the middle with fixed casters for extra support around the perimeter. I originally planned on just using a single larger lazy Susan bearing but the one I had ordered got lost in transit. I may update it in the future as I'm not 100% happy with amount of drag in the current setup but it does function fine.

Both designs use stepper motors and GT2 belt to mechanically spin the turntable with custom stand alone Arduino based controllers I built.

Since those photos were taken I found full GT2 belt loops of the correct length/size which allows for full 360 degree rotation on both turntables rather then the 180 degrees they were limited to before. I was originally worried about slippage using just a belt looped around the discs but found the tension of the 6mm GT2 belts on the discs themselves provide plenty of friction.

I still need to update the code to implement the full range of motion and I can switch over to my new improved controllers:

 

[TasTinker]

That is such cool lateral thinking TimVG!
I take it the front legs screw to the turntable? Also wondering if there's any tendency for the castors to pull it away from the set location as they rotate if you reverse rotation, or is that not an issue on a hard floor (or sticky pads under the turntable?)

 

[XMechanik]

Here is my take on the topic, simple and cheap.

components used:
- base of swivel chair, e.g. link
- terrace mast, e.g. link
- parallel mast mounting clamps, e.g. link
- plywood scraps for the tabletop

The mast should be sufficiently distanced from the chair's axis (using washers/sleeves) so that the rotation axis is 5-10 mm in front of the edge of the tabletop. Since the axis of rotation should be aligned with the front baffle surface, the edge of the tabletop will be hidden under the lower edge of the cabinet during the measurements.

The printed scale (link) lies on a stiff cardboard pad and it has a foam disc on top. The scale can be rotated with slight resistance relative to the base, which makes it easy to reset the pointer indication for the base setting. The pointer is made of two zips.

This is sufficient for a bookshelf, for a floorstander a support for V measurements would be needed.

 

[TulseLuper]

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Any chance you’d share the SVG for this? I also use a Shaper Origin and this looks great.

 

[napilopez]

Ugh y'all are so fancy and talented. Meanwhile this is me:

The amount of times I've nearly dropped a speaker...

Maybe if I ever start measuring speakers for real again I'll pay one of you to make me something nice.

One thing I'd like to investigate is the effect of different stands on frequency response. I'm quite sure I've had speakers measure slightly differently on different stands before, and found I got cleanest results if the speaker's baffle and the top plate of the stand was was flush with the 'mast" of the stand, or whatever you call it.

 

[TimVG]

That is such cool lateral thinking TimVG!
I take it the front legs screw to the turntable? Also wondering if there's any tendency for the castors to pull it away from the set location as they rotate if you reverse rotation, or is that not an issue on a hard floor (or sticky pads under the turntable?)

Due to the weight of the construction screwing down was not necessary. And it makes storage a bit handier. For reverse rotation I simply put the castors in the correct orientation by hand - it works very smoothly.

 

[TimVG]

Any chance you’d share the SVG for this? I also use a Shaper Origin and this looks great.

Sure thing

I don't have my computer on me at the moment but can share tomorrow. You'll need 11mm ball bearings.

 

[RickS]

A week later than planned but will get initial test run over the weekend, my turntable is built into the stand. I had a special as I need to swivel consistently on plush carpet. I initially had used a large plastic carousel, but it struggled to deal with the weight of the speaker stand. I mounted casters on the base and it is anchored by a speaker spike. You can see the extra wood block on the underside of the front of the base…

I have marked the outside edge of the base with the axis offsets and use a laser level from the back to help position accurately. Will get the equipment set up and see if I need to make on mods before I use for design measurements.

 

[TimVG]

How does the wide(ish) front affect the baffle step, Rick?

 

[RickS]

Not sure, having unplanned family visit today and my daughter’s car battery gave out yesterday, so have had no serious time to test as yet. Except for brackets is all wood. So can be trimmed as needed.

 

[RickS]

How does the wide(ish) front affect the baffle step, Rick?

Now, with first measurement, the answer is slightly (about 0.6 dB). Might live with it but already had cut angle braces just in case. So, will try with them instead!

 

[RickS]

My initial test was to do a short horizontal spin of the Dayton C-Note. Am pleased to report I was able to get good correlation with Amir’s review spin. I need to work on vertical spins next but just a matter of how to mount the speaker.

 

[publicfidelity]

Hey everyone!

Just wanted to share a quick project I recently worked on: an automated loudspeaker measurement turntable controlled directly from REW (Room EQ Wizard).

I built this turntable to streamline my loudspeaker measurements and make the process more efficient. With REW's API-control (Beta release), I can precisely rotate the turntable to capture data at different angles, allowing for spinorama measurements without the need for manual adjustments. The setup has been a game-changer for me, saving time and ensuring accuracy in my measurements.

Here are some pictures with a small explainer:

The table (made from the Audiomatica Medusa project files)

Table in action

I wrote a custom controller that uses the REW-API (in beta release)
This is log from controller:

It uses the measurement 'Increment' number as rotational distance input for the turntable.
The 'Repeated measurement' feature in REW allows for automated repeat.

Example of 0 - 80 degrees measurement sequence (gated)

Happy to answer any questions or share more details if anyone's interested.

 

[amirm]

That's really neat!

 

[eddantes]

Wow. Nice!