# What size disco/mirror ball?



## Steevo

Does the size of the ball matter to the size of the room and how slow the dost will be moving? in other words if i had a 20x20 room should i use an 8 in. ball or a 12 in. and would the dots be moving faster with the larger ball?


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## Les

The 12" would be fine for a 20 x 20. An 8" would work also, but you get a lot of wasted light because typically the beam of the pinspot will be larger than 8" diameter when it meets the mirror ball. So you might have light spilling around the mirror ball also. The speed of the rotation depends entirely on the motor used, but in general, if you were doing a side-by-side test of two mirror balls (one 8" and one 12", both on identical motors), the 8" will appear to spin faster because each mirror tile has a shorter distance to travel to achieve a full revolution.

Since you seem to be concerned mostly about speed, what you really need to be looking at is motors and not mirror ball sizes. Take note of RPM's and keep in mind that there are DMX versions out there in which you can control the speed though a lighting console.


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## venuetech

The smaller the mirrors the more reflections.
I like a lot of little mirrors.


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## hmhyde

*Mirror Ball Sizing*

Any rule of thumb for sizing mirror balls?


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## icewolf08

*Re: Mirror Ball Sizing*

I don't think there are any rules for mirror ball sizing. Just think of how obtrusive or inobtrusive you want it to be and how you are going to hang it and mask it (if it needs to be masked).


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## Footer

*Re: Mirror Ball Sizing*

The bigger the better.


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## derekleffew

*Re: Mirror Ball Sizing*


hmhyde said:


> Any rule of thumb for sizing mirror balls?


Ceiling height is the more determining factor than room square footage. ISTR, in the olden disco days there was a rough formula/ratio for ceiling height vs. ball diameter, but I don't remember what it was.


Footer said:


> The bigger the better.


Provided the bottom of the ball is at least 8'-0" AFF. Don't want the ravers knockin' their noggins.


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## Wood4321

*Re: Mirror Ball Sizing*

Also, 
The bigger the room, the slower the rotator. Unless you like to have vertigo


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## DaveySimps

*Re: Mirror Ball Sizing*

Great responses so far. I am relocating this thread so it is placed in a proper forum.

~Dave


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## FatherMurphy

*Re: Mirror Ball Sizing*

Best mirror ball effect I've ever seen was when a circus hung a ball in the middle of the arena, and blasted it with four Super Troupers, each a different color... I was sitting in the upper bowl, and it was a gorgeous swirl....

'Best' ball all depends on what you're wanting it to do - we've got a 42" ball for people who want to see a great big mirror ball overhead, and I've also used small ones on purpose so that it could hide in the rigging and not be seen directly, letting the dots have more of a surprise factor. Same with speed - are you doing a slow starscape, or running your audience through a blender?


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## gafftaper

*Re: Mirror Ball Sizing*

Best ball effect I've seen... Must have been 3'-4' ball. Then it was blasted with about a dozen movers all set to their highest color temperature white. All the movers had gobs in them that were sort of a round dot breakup. The gobos were all rotating at different speeds. The effect of the rotating gobo combined with the rotating ball was amazing. There were white dots wildly spinning around the room at a variety of speeds in an insane unpredictable manner. It was like being in the middle of a blizzard with wind blowing in three directions at once.


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## BillESC

*Re: Mirror Ball Sizing*

Important things:

Mirror tile size, the smaller the better.

1 RPM is best.

The more light sources the better the effect.

When Seals & Croft debuted their Diamond Girl album in 1973 to the east coast it was done at the Ocean Grove Auditorium next to Asbury Parkk on the shore. This venue seats over 6000. I had a contract to supply power distribution, communications and six super troupers with operators. The lighting co. touring with them had a 48" ball that they rigged over the center of the space. On cue on the D in Diamond, all six followspots hit the ball and the stage went form black out to blood red. I'll I remember is saying Wow.

Here's the auditorium... use your imagination.



BTW, Two Supers were located L and R at the top of the upper level as far forward as possible, slightly behind the mic line, two were mid building and the final two at the far corners. We hit the heck out of that ball. LOL


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## Ric

Les said:


> The speed of the rotation depends entirely on the motor used, but in general, if you were doing a side-by-side test of two mirror balls (one 8" and one 12", both on identical motors), the 8" will appear to spin faster because each mirror tile has a shorter distance to travel to achieve a full revolution.



Are you sure this is the case? The larger balls diameter would make the surface of the ball effectively be travelling faster & hence the dots of light would move faster.


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## avkid

*Re: Mirror Ball Sizing*

Very cool Bill, I've been meaning to see that place for a while.


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## Les

Ric said:


> Are you sure this is the case? The larger balls diameter would make the surface of the ball effectively be travelling faster & hence the dots of light would move faster.



Honestly, I don't even know anymore. Haha


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## Wood4321

Les said:


> The 12" would be fine for a 20 x 20. An 8" would work also, but you get a lot of wasted light because typically the beam of the pinspot will be larger than 8" diameter when it meets the mirror ball. So you might have light spilling around the mirror ball also. The speed of the rotation depends entirely on the motor used, but in general, if you were doing a side-by-side test of two mirror balls (one 8" and one 12", both on identical motors), the 8" will appear to spin faster because each mirror tile has a shorter distance to travel to achieve a full revolution.
> 
> Since you seem to be concerned mostly about speed, what you really need to be looking at is motors and not mirror ball sizes. Take note of RPM's and keep in mind that there are DMX versions out there in which you can control the speed though a lighting console.



I don't think this is correct, because 1 rpm is still the same speed no matter the size of the ball.
Yes the tiles will be going faster, but the light projected will be the same speed.


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