Help with rear MT122 panel

Are those faitalpro horns for the CD? I think I got the same ones, how are you liking them? 

Any tips on how to measure the cutout for them? 

maybe a bit late but what is time....

building these MT121 122 is VERY hard and timeconsuming. there is no real plan to do it.

build them on one side laying down, build the inner parts first, i guess it diesnt matter.

this thing almost has no 90° angles, which makes it so damn hard to do. i remember it took me months to a year to build 4 of them. i just cut to fit. and when i cut off too much, i corrected it with some glued in layers of cardbord. these things are a nightmare. i recommend documenting EVERY step u do on ur first piece, so u can refer to it on the next one. u have countless steps, that will make u insane, figure something out, endure, improvise... it takes time. and be carefull with deadspaces when using t-nuts!!! i had the pleasure while installing the mid-chassis and screwing in a bolt, a t-nut got pressed out in the back right into a dead space. i had to saw a whole in the wall, pick out the t-nut and reseal it. the feeling when sitting next to your almost finished cabinet and have to saw a whole in the sidewall..... just avoid it use some rampa inserts/threaded inserts or use woodscrews, when working with birch multiplex, u can use the same holes again and again when exchanging chassis. be focused working on the backpanel. when glueing in the rare panel stops, the parts where u put on the raearplate and tighten it with bolts, be as acurate as possible, just 1mm off in to deep or to shallow u will see at the surroundings - the rarepanel will protrude or sink in too much and u have to correct it (sand it down or router)

if i would build these again i guess id go for 2x the MT121 bcuz MT122 is REALLY heavy.