Let me be clear, all NAD processors (C658, T778, M33) have the distortion issue when any processing such as Dirac or bass management is activated. This is a hardware limitation due to lack of processing headroom. Tone control and using replaygain on can limit the distortion but will also limit the output level and scarify dynamic range. NAD cannot and WILL NOT fix this. This is the final replay I got after escalating the issue to their management:
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Hi Eli
Thanks for the sample. We have been investigating this matter for some time now. The inter-sample clipping (Rhye distortion) you are hearing is created at the time of recording on some "hot" tracks and cannot be resolved in any other way than reducing the gain on the track.
Please make adjustments accordingly. Sorry.
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There is no FW fix! This is what happens when digital processing is carried out using the original bit depth of the recording, you can easily run out of headroom. I've had it with NAD. I've ordered the MiniDSP SHD, which will be connected to dual Hypex NC400.
See other similar discussions about NAD distortion here:
https://www.audiosciencereview.com/...st-this-for-me-female-vocal-distortion.22151/