I did save many sets of REW measurements but the laptop is packed up…. Will post at some point.
However I dont think it helps to look at others measurements because every system/room is different and you can not achieve or do you want a perfectly flat response as you know.
By REW my target for my ears and room are approximately flat bass and roughly +5 db higher than the rest of the curve through 100hz and a slope down 5db to 150hz.
For me there were two issues in listening to the X3s in this room: muddy bass (which I did not experience in previous room) and in-my-face lower mids (which I have always experienced with the X3s).
Lets talk about REW, Dirac, and NAD (bluos observations)….
REW: I’M running REW on a quality laptop with SPDIF /optical out and a UMIK-1 usb microphone.
I have some confidence in the output from my laptop (which has THX certification on the soundcard), however I have no way of determining if the output signal is flat 20hz-20khz as I can not create a closed loop without spending money on an additional piece of equipment. With that said I did test an entirely different laptop and I did get the same curve in REW sending a 24bit, 48khz signal into optical….
I did do 1/6th octave curve smoothing during analysis (most people do 1/3rd octave smoothing).
Dirac: i do believe Dirac is very different depending on the component you are using and for NAD it appears to be made to be “easy”, dare I say “dumbed down”. I digress. I can choose to plug the mic into the NAD or into the laptop and the Dirac software will easily find either and simple calibration file incorporation. I chose to keep the microphone plugged in the laptop. After adjusting volume (my target SPL 75db at mic) and doing all the measurements…. Dirac default design is just two shelves… one bass and one treble shelf that you can slide up or down. Their default has a slightly higher bass shelf than treble and yes… mostly flat target with some rolloff on the high end.
I did listen to the default filter sent to the NAD and like many others it was good but “missing” for my ears. First, it’s very different in comparison to turning it off… but what I noticed is the soundstage is a little less warm but much cleaner and precise… which can put some people off. I did pay the extra $ to make my Dirac full range (not just bass). After moving the bass shelf up approximately 5db and saving that I switched Dirac mode to choosing my own control points (you can even add control points). This is where I brought some of the mids back and even some frequency response in 1-3khz region that default Dirac overly tamed (both by REW measurement and my ears). That completely fixed what was missing from default Dirac while maintaining the soundstage and unmuddy fast response in the bass.
The NAD c658: I knew going in this was not the perfect device that it could have been… no USB audio in, a middle if not mediocre DAC, and sub out handling as an afterthought.
However, I am all in with Bluos as I have other bluos devices and I love that I can easily stream high quality audio and it’s simple enough for others in the house to use and actually listen to music. I’m very much a “less is more” kind of audiophile. With that said it seems to pair nicely with the Parasound amp and sounds great… I have had no issues with hiccups or perceptible jitter. Sadly/oddly the NAD has balanced outputs for left and right channel but not the sub out.
The Arendal has dual balanced in and dual balanced out. At some point I am going to run xlrs from the NAD mains to the sub, and back to the Parasound. See how it sounds utilizing the incredible onboard dsp of the sub along with Dirac in NAD. I suspect in this scenario Dirac will not “see” the sub so I may not really achieve proper time domain correction. Thats for another time when I have 3 days to fiddle again. 😂