I’m confused with matching gain across my (DIY) system and after advice. The heart of the system is an RME UCX which feeds power amps with an input sensitivity of 1.4VRMS (or 0.775VRMS). This audio interface has +4BU and -10dBV settings on the analog outputs with manual stating that:
- High is +19dBU (0dBFSC) with 15dB headroom – calculated to deliver 16.7 VRMS
- +4dBU is +13dBU (0dBFSC) with 9dB headroom – calculated to deliver 3.45VRMS
- -10dBV is +2dBV (0dBFSC) with 12dB headroom – calculated to deliver 1.27VRMS
- So, assuming all things are equal, is it correct that the output of the RME should be set at -10dBV as the higher level +4dBU is too hot for the input of the power amp? (This seems to make sense although I thought that +4dBU was pro-audio set at 1.228VRMS so I might be missing something).
- Applying DSP (using Audiolense) sees a circa 20dB decrease in output across the various channels. What is the right path to addressing this issue given the above context? One option is to set the outputs to +4dBU but I’ve got no idea as to what this means for matching the input to the power amp(s). Another option is to insert a Topping Pre90 as a gain stage but this appears to have an input sensitivity of 9.2V at 0dB and outputs up to 50V P to P / 18V RMS which doesn’t seem to work.