I don't understand what you say? Down amp volume to 50V and next turn up the gain input in the mixer? This?
No. Set the amp input gains wide open. Set your mixer input control knob or slider to -0- or -∞-. Play a continuous 60Hz sine wave, and turn up the mixer input gain, until your amp outputs read the maximum volts possible. Using only your limiter, turn your limit control threshold until you reach 50V output from your amp. Without touching anything else, snap your mixer input control slider wide open
(maximum setting) while reading the voltage meter connected to the amp outputs. If the voltage doesn't move, your limiter is properly set.
There are no problems to put 0.7volt of sensibility in the amp if the mixer outup is 1Volt? Always read both would be the same.
This could lead to over driving and clipping the input. Not a good thing.
And the las 3015lf is the best option? I don't want to spend more than 200dollar or euros per driver
The T48 was designed specifically around the Eminence KappaLite 3015LF. There is an 18Sound alternative driver, if you wish to research if it is available to you at lower cost. Thomann
has the 3015LF in stock, available to ship to Spain, for 211€ each, including VAT and shipping!