Which DACs are known to be sweet/rich/relaxed?

Me posting here and asking for feedback is *exactly* that: delving into the source of my problems. I’m open-minded and not fixated on one particular solution or the other. Yes, my budget is substantial, but that does not mean I want to throw mud against the wall and see what sticks. I started this topic to learn.

I use REW to measure the room myself.

I did not mean you, I mean all the effectively "random" suggestions that amount to throwing money at the problem but fortunately sprinkled in, a few suggestions to attempt to get to the heart of the problem.

You already have (assuming working properly) about as perfect a DAC as possible. Anything else will add distortion, frequency response issues, etc. Looking at the ASR test, about the only issue is the slow filter.  If I understand things right, that is only an issue with a flawed recording. Others can probably pipe in better on that. Cymbals have lot of power at high frequency.

How does your REW plot look?  Are there any obvious peaks in the mid-range or high frequencies?

Here is an interesting page with cymbals and a discussion of frequencies with samples. It may be good for trying to isolate the issue.

https://www.musical-u.com/learn/percussion-frequencies-part-2-cymbals/

I listened again to Californication (from that album). The whole track has an edgy sound. I can't say any worse loud or quieter though. It does not sound like the best recording.

Also to consider is if perhaps there is something wrong with your amp or speakers that is highlighted with this music at high volumes. I have had issues in the past that only came out at high volumes (mid-range was failing).

Hmmmm,

I don't know anything about streaming.

Do you have the same source in LP, CD, HiRez Stream?

Is the LP more involving than the CD?

IOW, can you isolate the Streamer from the System Sound?

Have you considered a Tube Preamp?

Robert1976 - Perhaps you might audition the DCS Vivaldi (either with or without the Master Clock and/or Upsampler).  I recently made the upgrade and found it to be free of harshness and offers tremendous detail and richness.

@robert1976 

I second the general opinion about your server. Your system is excellent, the weakest link is the Root Nucleus.

I'm a big fan of Audio Note (my system is all AudioNote). My Server/Dac was not. I did audition the AN 4.1x dac with room nucleus at my home and it was a disaster. Not impressed by any means so did not spend the money. A couple of months latter visited the local Dealer for an audition with a Inous Statement and a HiFi Rose as servers. Completely blown out. So much so that I purchase the Dac, waiting for it to be delivered with a Rose as server.

I would not change your Dac before testing  a dedicated server in your system.

Best 

@robert1976, You answered your own question in my opinion. “I used to have a Dan D'Agostino Momentum Integrated. I'd use the tone controls and simple cut treble 1 or 2 dB. I don't have that flexibility any longer.”

Sometimes the simplest solution is the best. As others have noted, recordings of rock music are often not the greatest, especially recordings of live concerts. What no one has mentioned is that the level of distortion produced by the gear used to play rock music, the amps, specialty pedals, speakers, cables, everything, are generating loads of distortion, some of it intentional. 
 

You have a wonderful, neutral and highly revealing system. Do you listen to much acoustic music at high volumes? If so, do you find the high frequencies of symphonic music, string quartets, acoustic guitar, that is, classical, jazz, folk, bluegrass, etc. equally edgy? If not, it’s the recordings.

If rock is not your sole interest and the system sounds great during most of your listening, look for a different software approach or purchase a high quality equalizer that lets you cut the treble a bit for those recordings that require it. 
 

Someone will always want to sell you a $20k something. You noted you tried Roon’s equalizer and didn’t like what it did to the rest of your music. You will likely have to adjust for the specifically annoying recordings only no matter what solution you select. Find someone who can suggest simple high quality software or hardware to reduce treble output at the frequencies where you find it annoying. Perhaps other Audiogoners can suggest some options.