The miniDSP provides RoomEQ in one box, but does not have instrument inputs eg you can’t connect your guitar or a microphone needing 48V phantom voltage and feed them into your PC (eg DAW, VST amps etc). Secondly for guitar playing you generally want minimum latency in your system because it is otherwise irritating for the player. Audio interfaces generally have better overall ADC and DAC latency.what's the benefit of having a Mini dsp vs an audio interface?
The mini DSP has usb, would I be able to connect to my PC with that?
would i have to replace my audio interface with Mini dsp?
Therefore I did not recommended the miniDSP for your particular purpose as you would still need your Audio interface. Sure you can connect the MiniDSP in between your Audio interface and the speakers. In my opinion a waste of money and would add even more latency, plus you loose the balanced connections.
Alternatively to the MiniDSP you can do RoomEQ (same as MiniDSP) with your PC with free EQ software called APOEQ and feed the corrected signal via your audio interface to your speaker and still use VST guitar amps and or your DAW for further guitar effects and your audio interface for recording/guitar playing.
Any suggestions are welcome. Post suggestions here. I will gather the details and add them. Thanks. :D This will be organized as results come in. @sweetchaos made a guide for PEQ filter data input and operation. For crossover software go here. Windows: Equalizer APO is a parametric / graphic...
For both the miniDSP and APOEQ you need a 100USD UMIK1 microphone and REW(free) to measure your room response and derive the filters which you either plug into miniDSP or APOEQ.
I hope that helps you a bit in your decision making.