I appreciate your frustrations, but you seem to be expecting Rolls Royce standards of service when you bought a Reliant Robin... As the support agent said, he only has access to the same published info you have. It's not great, but at least you got to speak to someone. If you're nice to them they might go and ask someone who really knows for you....
... please, explain why on this position, the input signal is hitting +10 dB on the EPM6 level meters, wile the Reloop RMX 60 master output registers 0 dB on its level meters on balanced connection?
First, as Wonks said above, unless you're testing meter levels with steady sine tones all bets are off. Meter dynamics can vary wildly on audio material.
If you are using a sine tone, the difference in meter readings simply indicates different nominal operating levels between the two devices and/or unwanted gain being introduced in the mixer input.
The simple and obvious solution is to turn down the mixer input gain or the dj console master output level, or both. These controls are provided specifically for that purpose — to match the output level of the source to the input level of the destination. This is gain staging 101. Who cares where the knob is pointing?
Let's pay attention to what they say in the Soundcraft EPM6 mixer description which states that the mixer "provides a stunning +22dB headroom through the console." According to the EPM 6 technical data sheet, the main mix maximum output level is +20 dBU.
This would mean that the nominal output level (0 dB on the meters) of the EPM 6 master output is -2 dBU...
No, it doesn't.
First, you're assuming the maximum output level is the same as the internal clipping level. Depending on the output driver configuration this may not be the case. It could be as much as 6dB lower...
However, ~if~ the internal clipping level really is +20dBu, and there is 22dB of internal headroom, that would imply an internal operating level inside the desk of -2dBu, which is actually a very common figure. If there are any insert points they will also operate at this level.
This 'depressed' internal operating level is commonly chosen to maximise headroom through the channel preamp, EQ and mix bus stages to accommodate uncontrolled input signals without overload. Most mixers, even high-end professional models, use the same approach for the same reasons.
It is expected that these uncontrolled input signals will be suitably managed and mixed to a smaller dynamic range at the output, which can therefore operate with less headroom — at least in a budget product like this. It's a cost-effective but practical compromise.
And second, the meter zero is always calibrated to indicate the rated operating level at the desk's output connectors. It's probably +4dBu, although it could be 0dBu (Mackie mixers are calibrated for meter zero=0dBu, for example). The meter zero certainly does NOT indicate the depressed internal operating level. That would make no sense at all.
I have to say, much as I'm a technical geek that likes to align things accurately, I'm really struggling to understand the problem here. The two units have different operating levels. It's not unusual. If you want the mixer meters to match the dj console meters just adjust the output level/input gain as necessary. Job done.
