Is anyone using a 2017 iMac and playing audio via USB to an external DAC and then onto powered speakers? I have spent a lot of money changing DACs and cables but still get a crackling noise from the speakers. If I plug a Blu-Ray player directly to the speakers via phono cables then the crackling noise is not present. Also, strangely, if I plug headphones into the DAC then I don’t hear the crackling noise either. Speakers are KRK Rokit 5. I’ve reduced the noise by using a very high quality USB cable between the iMac and DAC. The only other thing I could try is another set of speakers but that’s a very expensive option. I’m going to try using the 3.5mm headphone out on the iMac directly connected to the active speakers via a 3.5mm to RCA cable. As the iMac is just a few weeks old then I could contact Apple and I’m so disappointed as it’s cost me around £3.5K for the iMac and I get very poor audio quality from it, plus Apple has limited the digital audio output to USB only.