@Icemud420 what's the closest u can hang the cpb x4 in your personal opinion so she doesn't bleach n shiz n same applies for the x9 I've em at like a foot from the canopy
When I took PAR measurements on the COB 4, center PAR was aruond 1180 umol/m2/s-1 which for indoor without co2 is about ideal, maybe even a little too much. So I would say anything greater than 1 foot from the canopy should be ideal, and 18 inches at center was around 580 umol/m2/s-1 which is still within ok range for flowering. I wouldn't go much further than 18" for flowering with the COB 4.
With the x9, I've never tested the readings so I am not sure what "range" is optimal. I don't think the PAR measurements on the X9 from the website are right because its showing less intensity than I measured with the X4... so I think that its an error on the posted readings. I would say with the x9 you should keep it probably 14-18" away based on my guess of intensity.