CXB spectrum vs output

@mduke pointed out that Cutter (THANK YOU Mark @welight ) posted the SPDs (based on photon count) for some of the most popular CXBs and it takes the bin into account, the 3000K 80CRi CB, 3500K 80CRi CD and 4000K 70CRi DB. I tried to adjust them to be relative to each other in this gif

In Mark's test the 3000K = 3044K, the 3500K = 3375K and the 4000K 70 CRi = 3784K. The 4000K has the highest photon count and it has the least of its output above 700nm (where photosynthetic efficiency is known to drop off quite a bit). The 3500K has only slightly more output above 700nm, but not too bad.

Keep it up Amigo, very good work you do for us.

Then the 4000k is better to use than the 3500k ?, I am asking because I am ready to order some cxb 3590 3500k cd, and I believe 4000k is better for both vegging and flowering or maybe I am wrong.

Thanks @welight.

Is consistent with what I got in the calculated K temps for 3000K(3053K) and 3500K(3357K)



We know the 70cri. 80cri 4K is what we should be curious of. I can get it later if we need it. I know the bin is what people are after, but 70cri on it's own is not going to work perfect with everything like some of the lower K's will. I've put a few runs in with straight 4K.

Greengenes707 said:

Thanks @welight.

Is consistent with what I got in the calculated K temps for 3000K(3053K) and 3500K(3357K)

View attachment 3576490 View attachment 3576491

We know the 70cri. 80cri 4K is what we should be curious of. I can get it later if we need it. I know the bin is what people are after, but 70cri on it's own is not going to work perfect with everything like some of the lower K's will. I've put a few runs in with straight 4K.

Click to expand...

what makes the 70 CRi 4000k not work from your experience? The SPD graph of the 4000k looks better than both the others and its like 5% higher efficiency than the lower kelvin COBs. I'm just curious because IDK. Were the buds looser? was the product not what people are used to?

If you could tweak the 4000k spectrum, how many watts and what wavelength of red would you recommend? hyper red 660?

sponge mode !

I have also had good results from the 4000K 80 CRi CD in flower, but have not tried the 4000K 70 CRi DB.

In veg, I have had good results from the 5000K 70 CRi CD and recently the 5000K 80 CRi CD became available. I expect the 4000K 70 CRi DB would be an even better veg light than the 5000K CD in either CRi.

My experience is with 80cri 4K, and why I am asking. 80 cri 4K on certain strains has noticeably less bulk and size of buds. Some strains there is no difference at all. As where I have been getting consistent development from 3K and 3500K.

The 80cri should have a more red shift overall vs 70. So I'm just curious since they are doing testing, why not. They are cool guys.

thanks @Greengenes707 @SupraSPL and @Growmau5 for all the utube vids and for leading me to all this info, THANKS. I am thinking about using cutter and their prome cutandroll seems like the best deal I can find. this is my first light build. will be going with cbx 3590 3500k, do I need to mix in 4000k too are just go all 3500k?

Bonjour
I often heard that when you mix a 3000ºk and a 4000ºk you will get a 3500ºk...but it is not what I see when I watch the spd's...
I was thinking about add 4 x 4000ºk to 8 x 3500ºk in a 4x4...to get more blue...or 4 x 3000ºk to get more red...I can't made my mind!?!
I am at a week from the cut...I will now soon...lol!
CU

littlejacob said:

Bonjour
I often heard that when you mix a 3000ºk and a 4000ºk you will get a 3500ºk...but it is not what I see when I watch the spd's...
CU

Click to expand...

me too ... there is no substitute for actually measuring instead of assuming what your "supposed to get"..

assuming & knowing the facts
man the DIY Mind Bork ......

i was wondering the same a mix of 500+/- difference
I take of faith in what I've read then I'm gonna leap if I'm froggy I'm gonna buy more any way

led2076 said:

thanks @Greengenes707 @SupraSPL and @Growmau5 for all the utube vids and for leading me to all this info, THANKS. I am thinking about using cutter and their prome cutandroll seems like the best deal I can find. this is my first light build. will be going with cbx 3590 3500k, do I need to mix in 4000k too are just go all 3500k?

Click to expand...

I agree with the previous posters. 1 + 1 does not always equal 2 in this case. mixing one 3k and one 4k is not going to give you the same spectral graph as a 3500k. My advise, mix it up, try it, and report back here with your experience, unless you have a spectrometer.

A lot of guys around here (myself included) have done entirely 3k runs, 4k runs, and 3500k runs. the differences are subtle to my eye. I think more depends on your abilities as a grower than a 500k shift in color spectrum.

***please please report back with your experience using Cutter. particularly how the coupon code and currency exchange worked out on your credit card statement. I would appreciate that greatly.

I would think mixing 3k and 4k should only be done under certain conditions,maybe with harder driven COBs with some distance to mix properly. My lights would not be a candidate,bare COBs at 800ma and 1 foot apart and close to the plants,no room for proper mixing.

I got to tell you its amazing how some will get so deeply involved which is great and like above post mentions how they grown 3 k 4 k and 3500 k runs and differences are subtile to the human eye as in bud size etc , i think people need to test THC and overall quality and really fine tune it to what its k is really doing what so after comparing THC content and other qualities , then yields per then mix matching K's to get into the best possible in both yield and resin output i am actually going to wait a bit and see what else comes out

But i got a question ??? for the Diy Hards can you use VERO and CXB in sequence on same panel build or is there issues

^^^ yup.

Guesswork is a gamble.
Why not make a simple spectral analyzer? I'm just waiting for my webcam so I can put mine in action, and start measuring the spectra of my LEDs. The plans for these devices are widely available on the net, too.

https://publiclab.org/wiki/spectrometer

I made mine from a breaded-chicken box, a 500 lines/mm diffraction grating ( via some cheap glasses I scooped from an old chemistry class...I knew they would come in handy), and some black cloth to line it. Two razor blades to make the slit, and a piece of scotch tape (not the clear type) to act as a diffuser.

I was surprised to see my 4000K phosphor was missing a big chunk of blue (it appears to be missing from 450nm-500nm), but until I get the camera I won't know exactly.

It may not be a JAZ-spec, but it is certainly better than just guessing, and FUN !!!

thats pretty cool stuff

heckler73 said:

Guesswork is a gamble.
Why not make a simple spectral analyzer? I'm just waiting for my webcam so I can put mine in action, and start measuring the spectra of my LEDs. The plans for these devices are widely available on the net, too.

https://publiclab.org/wiki/spectrometer

I made mine from a breaded-chicken box, a 500 lines/mm diffraction grating ( via some cheap glasses I scooped from an old chemistry class...I knew they would come in handy), and some black cloth to line it. Two razor blades to make the slit, and a piece of scotch tape (not the clear type) to act as a diffuser.

I was surprised to see my 4000K phosphor was missing a big chunk of blue (it appears to be missing from 450nm-500nm), but until I get the camera I won't know exactly.

It may not be a JAZ-spec, but it is certainly better than just guessing, and FUN !!!

Click to expand...

You can even look up the quantum efficiency for the CCD of your camera and correct your measured spectrum for efficiency of the CCD