DAC + Preamp + Room Correction, NAD C658 / MiniDSP SHD / ?

I'm wondering if there are any alternatives to either the NAD C658 or MiniDSP SHD that cover the same functionality?Both are streamers, DACs, preamplifiers, and have Dirac Room Correction.The streaming is less important, but a nice feature.

Any informed votes for one over the other, or other recommendations?
The miniDSP SHD unit has advanced routing, crossover, and PEQ functionality in addition to Dirac Live room correction. Which makes it very versatile and useful. Plus you can do all of that in the digital or analog domains. We started carrying the SHD units because they're super useful, powerful, and easy to integrate outboard boxes that can be integrated into just about any 2.x setup.
Oddly enough, few if any of the alternatives have a streaming (Ethernet) input. Maybe the Classe Delta Pre at a cool $10k and as yet unavailable.

Of the two you listed, I chose the SHD. As it’s in our TV system, I can’t comment on absolute sound quality, but it sounds very good feeding our Audioengine A5+ powered speakers, whether streaming high-res files or decoding the TV’s output. It has worked reliably, and I’ve found the Dirac RC and miniDSP software quite easy to use. Also, it’s a little cheaper than the NAD. Finally, unlike the NAD, it has Dirac right now -- I dislike buying anything for the features that will be released "soon."

People seem to like the BlueOS used in the NAD. But many of us are happier to have the plain Open Home/UPnP interface of the SHD, which is interoperable with a wide spectrum of other units.

The miniDSP does show a little evidence of having been assembled from components, rather than being engineered from scratch. For example, the miniDSP app won’t control it, apparently because the SHD’s Ethernet port is connected only to the streaming board. One can buy a doodad from miniDSP that receives wireless signals and outputs a control signal to the SHD’s USB port, but that is an extra expense and then takes up the only USB input. But really, that’s a small issue, and the SHD does have a fully functional IR remote control.

So for price and function, I chose the SHD. It sounds good to me. I can’t see why the NAD would sound any better.

Hope that helps.

P.S. I think, but am not sure, that the NAD offers only fixed crossover parameters for subs, while the SHD offers complete control of slope and frequency.

I'm with you OP trying to figure this out myself. I'm a new audiophile having KEF R3 L/R, Dual Rythmik F12SE subs, run by a Yamaha A2080 AVR.

I'm contemplating buying the Arcam SA30 when it comes out this fall.  It's a Pre/Power/Streamer/MQA/Dirac. Run in HT bypass mode for movies.

My goal really is to get Dirac into my system for 2-channel (or 2.2) music.

But it's tempting to start adding separates incrementally now.  Power amp to AVR, then I could do something like the NAD C658 w/Dirac or minidsp HD... Or total separates after the amp like then mini dsp, DAC, amp.

Anyway, the Arcam SA30 could be an alternative option for you to look into.  :)
been thinking about this quite a bit meself...
#1. I was really interested in the NAD C658 but the unit has not been reviewed very well regarding SQ, generally. I do see a few folks that are happy. Dirac Live should make a difference.

#2. This is my favorite... the TEAC NT-505 at a whopping 2K USD. This kit has all kinds of electrical mojo and power torroidal bits with OP amps so good you can eat them, or at the very least become aroused by opening the box for a gander. I don't need the streamer though as I am using my MacBook Pro to Audirvana to Balanced XLR to powered Monitors...

#3. Today the nice lads at MassDrop have informed me of the Topping D70 with dual AKM4497 chips and balanced outputs for $425 USD. There is no MQA which I really want, but this unit can be turned into a streamer with some voodoo doodad and pressed into Television-HT duty at a later date... and all 4 outputs can be be used at the same time.

whatever I get I will probably buy a UMIX mic and either use REW or the Room EQ (100 bux USD) AU plugin that is directly integrated into Audirvana. The miniDSP SHD is cool but the DACs are older and I am not gonna buy the box just for an XLR balanced connection and Dirac Live + another outboard DAC. 
Two thumbs up, way up, for the minidsp SHD. In the past I have not been satisfied with the integration of my 2 open baffle Rythmik subwoofers with my German Physiks Carbon speakers. The SHD performs this function flawlessly. In addition the Dirac room correction is amazing. The unit is dead quiet with absolutely no speaker hiss.
while I am certain that the miniDSP SHD is a fine bit of kit and sounds great... it uses AKM 4490 chips while most current HiRez boxes are at 4497 chip line. I do not see that it will decode DSD natively. No MQA.
If you just want PCM and Dirac it will be outstanding. This is one box that I am very interested in hearing.
@canibefrank: In your consideration of MQA, I suggest you review the history of another lossy, proprietary codec that once was the darling of the audio magazines:  HDCD.  Today, it's lost in the dustbin of audio history; yet when new, purple prose came from the audio writers (in particular, one Robert Harley) of a volume and pitch not seen again until MQA came on the scene.

Like everyone, you will (and of course should) make up your own mind. It never hurts to revisit audio history.