MiniDSP DDRC-22A / Dirac Live in 2.0 Living Room System

[KxDx]

Hot off the heels of improving my maelstrom of a mancave with a MiniDSP DDRC-22D, I obtained its analog I/O cousin the DDRC-22A and implemented it into my 2.0 living room system.

The heart of the system is the Marantz NR1200 AVR. It makes going 2 channel easy, and it has stereo preamp outputs, which allows me to insert the 22A into the chain. Amplifier is a Niles SI-2150, same as I use upstairs.

Speakers: McIntosh LS360's. Dual 10's like I like it, and an interesting 8" large midrange and 5-dome tweeter array. These speakers have a GREAT midrange presence. I wish I could swap then with my T&A's upstairs but nobody wants to help me move them! I'm so glad they're front ported so the grills prevent Legos and Barbie dolls from winding up in the ports. They are specced for -2dB at 29Hz which should prove more than adequate for almost anything we watch. I didn't want to take the straps (grandkid-proofing) off to remove the grills so here's a stock picture stolen off the internet (actually it’s my pair of speakers in the previous owner’s house).

The speakers flank a custom-built AV shelf / dog crate. Smile Hazel, you're famous!

This is a large, open, acoustically difficult space. Unlike my room upstairs, the living room is anything but cuboid. Behind the sofa is the stairway.

To the right of the couch opens up the hallway, and the pantry /kitchen area.

To its left is the wall for the front of the house.

The ceiling slopes around 20? degrees and is at least 15 feet high at its peak (as a side note, this is why it stays so damn cold in there during the winter).

 

[KxDx]

Typically, 1-3 people use the couch so my REW measurements will be at the center (MLP), left seat, and right seat, based on my ear height.

To get my measurements through REW via the laptop, I had MacGuyver this together: 1/8" stereo to L/R RCA cables, into RCA to XLR adapters. I have a newfound appreciation for bygone Radio Shack and its wall of Force Feed. I could have gotten all this in one quick trip to the Shack back in the day, but now it's Amazon Prime and wait 2 or 3 days.

A side note, I noticed that all of my REW measurements for this project normalized to -10dBr. This loss is from the unbalanced source going into the balanced DDRC input. It's also present when using the NR1200 and we have to turn the volume a lot higher for the same levels we were used to. I've ordered an ART Cleanbox to restore the signal level and remedy this. However the purpose here is showing relative changes in the frequency domain so I probably won't re-measure.

The untreated room doesn't look as bad as I thought it would, to be honest. Whereas my upstairs cuboid room had a dominant +15dB gain at 40Hz, the living room has an almost even plateau across the bass spectrum. However 2 problems are immediately clear. The first is that bass response falls off a cliff at 35Hz. The speakers aren't even close to reaching their low-end potential. That measurement confirms what I've felt since I bought the speakers- that those 4 giant woofers weren't bringing the low-end pain like one would expect. Second, that huge null at 87Hz. Spoiler- Dirac couldn't fix that one. It's endemic to the room and I've got to live with it.

The low frequency discrepancies at the left and right seats show just how much this uneven open space fucks with the bass. Mids and highs look really good however, and don't need much attention at all. McIntosh's large midrange and Bessel array do a fine job.

 

[KxDx]

After Dirac Live did its calculations, I created 4 filters. The first is Recommended, which is what the algorithm calculated (about a 2dB bass lift and -0.8dB highs). It was a bit anemic for my tastes, honestly. The other 3 filters I made myself... Preferred, (+7 / -1.0). Dynamic, (+10 / +1). Flat, (0/0) for reference purposes.

Dynamic is great for low volume listening (when you still want some impact) as well as those times I want to blast action movies. I watched a couple flicks on that setting, and left it on for the Super Bowl. It was impressive. "Preferred" is what I'll use most of the time though.

Post-processing Measurement time!

Here's the measurements for each of the 4 filters. Starting with Recommended:

Preferred:

Dynamic:

Flat:

Right off the bat... THERE'S that bass extension! Instead of a brick wall at 35Hz, Dirac fixes this to what I would expect of these speakers, with a more natural slope beginning just at 30Hz. Now I have usable bass down to 25Hz. The difference is striking. Even though the Room curve and Preferred curve look a little similar, the fullness of the plateau and the extra extension are night and day. Subtle bass cues were much more noticeable and the presence during impactful scenes provided that sweet punch in the gut. That 87Hz dip couldn't be fixed. It's most likely a front-wall to back-wall cancellation mode and only repositioning or a sub will improve it, and both of those options are off the table. In real world listening, though, I never perceived any absence of bass in correlation of what I was seeing on the screen.

Frequency wise, not much got changed in the mids or the highs, which I didn't expect from an earlier observation. But what the frequency graphs don't show is the improvements Dirac makes in the time domain. The sound stage width improvements are just as impressive as the bass response. No I wasn't magically hearing surround effects from 2 speakers, but if I were to close my eyes I would swear my speakers were much, much farther apart than they actually are.

 

[KxDx]

Here's my room curve directly compared with the Preferred curve, for all 3 seating positions.

Main:

Left:

Right:

 

[KxDx]

Conclusion... If there are downsides, the first I must mention is that the DDRC-22A has a high noise floor. Much like the DSpeaker 2.0 the DAC side produces audible upper frequency noise. This was NOT audible from my seating position, but up to 2 feet away from the speaker I could hear it. The DDRC-22D (SPDIF) version has no such issues, but I couldn't have used it here since the NR1200 only has analog preamp outputs. Someone using very high sensitivity speakers or a nearfield listening setup might be annoyed. The other issue is lack of unbalanced RCA input/output jacks, so you will have to spend a little bit on some extra equipment if your preamp and/or amp don't have balanced connections. And of course there's the little bit about this version being discontinued, so you'd only be able to get one second hand.

Once again Dirac Live made improvements so profound that I wish I had bought these units years ago. I'll never live without this kind of processing again. In 2 separate systems, 2 completely different types of rooms, the end result was improvements that I could measure as well as hear.

 

[Deleted member 48726]

Dirac and DDRC24 is the best thing I ever bought in HiFi.

 

[KxDx]

Dirac and DDRC24 is the best thing I ever bought in HiFi.

I could kick myself for waiting this long!

Here are the last 3 graphs again, zoomed in to 20-300Hz... since that's where the most improvement was done. (reminder that -10dB is actually 0dB)