The big improvements occur with the room correction. In the perfect room with the perfect speaker layout, Dirac is great. As your room gets less ideal and your speaker layout gets less ideal Trinnov is better.
I would say you get to 70% of the quality with a premium soundbar setup, 85% with a Sony or Yamaha receiver, 90% with a standard AVR from Denon/Onkyo/JBL, 97% with a AV10 or HTP-1 if you can use extra channels and then 99% with the Trinnov. I say this having gone Sony to Yamaha to HTP-1 to Trinnov Altitude32. The real strength of the Trinnov line is future proofing. Their track record has been great for releasing new features and hardware upgrades as appropriate. The big paradox is that people with the worst layouts are the ones most likely to benefit from 3D remapping but it’s people with dedicated home theater build outs that can budget for the Trinnov…
Going back to the question. Nothing will beat buying better speakers for your setup. Putting $3000 into a premium center channel or more “musical” subwoofer (group delay, distortion) will help a lot.
The Monolith HTP-1 is a very reliable product with excellent features and value. Dirac full range is included with the HTP-1 and it is one of the only systems with the ability to apply loudness on top of Dirac. You get Atmos and Auro 3D upmixers and it works great. The weakness is that you have to be a tinkerer as you will be relying more on community support than a dealer or manufacturer for support, and you have to be happy with the feature set as is.
With Dirac, your speakers should be in a good location.
If you don’t have the best location for your speakers, I tell people that your best bet outside of a Trinnov is a Sony or Yamaha AVR. The Yamaha AVRs get criticized for poor SINAD, but it’s inaudible and it’s designed for 1V outputs, which is fine with your McIntosh amp which is also intended to operate with 1V input sensitivity on the unbalanced inputs. The Yamaha Cinema DSP works great for music and creating that bubble of sound. It’s not at all like setting the reverb setting to on or any of the sound modes from other vendors. The Yamaha A8A has a lot of discounts at times from places like Adorama.
It’s been measured by enthusiasts with a SINAD of 100 dB at 1.6V XLR (which should be similar to 0.8V RCA)
The Yamaha runs out of steam as you increase the voltage, meaning it’s a poor match with today’s class D wonder amps with lower gain, but for your McIntosh, the processor won’t be limiting your performance. You would run “YPAO RSC with 64 bit precision” for your room correction and then use a UMIK-1 to fine tune your results with PEQ. The better your speakers are, the less critical the full capabilities of Dirac are. Yamaha does a good with room correction — not speaker correction.
Edit: I run a 5.2.2 right now with my Trinnov. I have used quad subs to experiment with Waveforming (works great) and I am adding some front heights. My room and speaker layout are very compromised…