NAD C658

I owned it for about a month but sent it back. Dirac was late and still undelivered at that point so I can’t comment on that. I just wasn’t happy with the overall sound - a bit too clinical for me but that's personal preference and MANY people love theirs. For the price it wasn’t terrible but wasn’t what I was looking for. From a functionality standpoint it was great though and I still sometimes think about going back just for that reason. Especially since I never got to experience how it would sound with Dirac.

One thing I would note is it takes a while to burn in and had a large improvement once it did. The soundstage especially changed, starting out as normal, nothing special, but after burn-in it was pretty remarkable.

Check out the long forum post about it over on AVSForums

I'm not using the Dirac, haven't tried it. Should I? 

Milestone product: killer streamer, pre, dac. MQA, Blusound, built like a NAD. Great price. Aptx bt but I don't use that. 

Dirac is one of the reasons I am looking at it. I like the bluOS easy to use and having everything but the amp in one box looks good to me as well down size a bit.

I'm been loving the Dirac 1.# + VST plugin since 2014 and this week I finally got the same working in Dirac 2.4.1 -- I'm exporting the filters to a VST plugin (hosted in JRiver26) running on the same computer.  Would be cool to try exporting a filter to an Arcam or NAD streamer.

I purchased my C658 this week and love it.  I primarily purchased it to stream Tidal HiFi (including MQA).  Out of the box it sounded just ok, but I've left it on for several days now and it sounds better every day.  Streaming Tidal sounds better than CD.  I'm also trying out the internal phono pre-amp versus my internal PrimaLuna phono stage.  At this point it certainly isn't obviously inferior or superior.I set up the DIRAC Live today.  I wouldn't say this is a game changer at this point, but I haven't tinkered with the optimized equalization that the software develops.  At this point the DIRAC derived sound is tighter in the low end, smoother, and slightly subdued.  The BluOS app seems solid.I hope this helps