I had the problem that the output of my RME Babyface Pro (the old model) has a fixed output that drives the Tannoy Gold 5 monitors too hot.
The result of this is that the main output of the sound card had to stay at -40dB, lowering the resolution of the audio and pumping the self noise. In the rme forums ("Level mismatch solutions - fixed and variable attenuators"), they suggested this product and I admit that they work perfectly to attenuate the sound card output so that I can turn my main output back to 0dB.