4x Color Wheel = 7200 RPM, 5x Color Wheel = 9000 RPM, 6x Color Wheel = 10,800 RPM
Originally Posted by plainman007
If a PJ has a 6 segment color wheel and says on the brochure that its 6 segment with 2x speed and mentions 7200rpm right there too. Is this actually running at 4x speed because a six segment wheel refreshes the primary colors twice during each rotation ?
The PJ also mentions that when Pal content is used with 50Hz setting on the PJ then the wheel speed goes up automatically to 3x and it mentions 10800rpm. Is that actually 6x speed due to the 6 segment wheel ?
Sounds like you are talking about one of the Optomas, they are likely referring to 2x in 120hz mode, but we generally think in 60hz when speaking of color wheel speeds in the forum. The manufacturers seem to love to keep color wheel speeds under wraps or let confusion about it go unanswered, as they rarely cleanly disclose the workings of the color wheel. If they give the RPM's and # of segments, then that's a dead give-a-way as to what the color wheel speed is.
Some MFR's will refer to the 60hz instead, but lately most are referring to 120hz. The color wheel speed is still spinning at the same actual RPM speed between 60hz and 120hz. When a projector is displaying 120hz, it means twice as many frames are being displayed per a full rotation compared to 60hz, that's why some call it 2x and at other times they call it 4x. Not to confuse you more, but this is a different issue from the color wheel changing speeds for 24p signals to convert to an indivisible multiplier, in this example the RPM actually changes speed.
Some wheels also have an extra segment (7-segment color wheels). Some Marantz and Planar I believe have the seventh segment, the only cheap projector I know of that also has a non-white 7th segment is the Viewsonic Pro8200, in its case it is RGBRGBY, the Y is a yellow segment which functions kind of like the white segment, except not quite as intrusive or damaging to the colors as a white segment can be.Edited by coderguy - 9/1/13 at 6:01pm