Dealing with 1 high level input and 1 low level input to a single output?

[l0u5y]

Hi. I have a cd player and an output from my PC(soft synths, CD, MP3, etc) going into a pair of KRK RP5s. I also have a Presonus Firebox connected to my PC which i use for everything thats coming out from my PC. I wish to have as less quality loss as possible. My RP5s have a TRS input, XLR input, RCA input. I tried connecting my CD player straight into my RP5s and i realise that my CD player is much much louder than the stuff from my PC even at the softest volume. I am thinking of taking the S/PDIF output from the cd player into my Presonus Firebox but I don't think i can control the volume of both the cd player and my PC separately and i might also end up with the same result before. I need to bring both outputs to the same level. So how should I approach this? Thanks.

 

[soft]

What is the purpose of having the CD Player and your Computer playing back at the same time?

To solve your problem, a small mixer will help. Something like the Yamaha MG102C. Just connect the output of your Firebox and CD player into the mixer. Mixer Out to your monitor speakers.