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Oh Room Correction, how Far You've not Gotten

I have been excited about digital signal processing (DSP) since the early 90’s. I remember, naively, only thinking about frequency response, then thinking about how it might be useful in overcoming stored energy problems in drivers, and even compensate for compression, anything that could be mathematically modeled. Along with this was the servo controlled speakers from Velodyne and Genesis. Oh what great ways we’d have to overcome the limitations of driver design and even physics itself!! The infinitely powerful, all knowing computer of Star Trek applied to audio would surely solve everything and make it possible for every average music and film lover to have mastering studio quality sound.

After having great success with manually configured miniDSP units in my modest apartment in San Francisco and movies I wondered to myself how much better would a "real" room correction algorithm be than what I could tweak by hand. I read a paper by Floyd Toole where he scoffs at the idea of "room correction" altogether. Surely Mr. Toole, this paper is now old and has been superseded by modern research! Surely room correction is now worth it’s label!

After living with and playing with the Anthem room correction built into the MRX 520 I can tell you that for at least this example, Mr. Toole remains undefeated. Don’t get me wrong, it’s a decent HT receiver, far far better than one’s I’ve bought and discarded before. Also, the subwoofer integration and web interface are pretty sweet. What it does not really do well at all is create an immersive or enormous sound field which I was able to get before using miniDSP and OmniMic.  I have big booms but not the credibility and transparency I was able to create by hand tuning the EQ.

Over the rest of this year I’ll spend more time and money investigating exactly what ARC does, and whether or not I can do much better by hand tuning.

A really frustrating part of my purchase is that this amp does not give me any sort of ability to set and modify individual filters. I have some overall level controls but nothing like the sort of control more advanced DSP software gives you.

P.S. - Many of you will automatically and correctly point out that room treatment solves many problems that DSP/EQ cannot. Yes, that’s true, but this is a well treated room already. I’m specifically looking into what the ARC has done or failed to do in the frequency domain.

erik_squires
arion's avatar
arion
156 posts
 

Erik,

It's good to hear from someone who, at least, is open minded about DSP/Room Correction. First, by definition, DSP exists everywhere there is a digital signal. Furthermore, the term "room correction" is a bit misleading. These systems do not correct the room. These systems alter the signal (in the digital domain before amplification) so the output from the speakers and the contribution of the room work together for better time domain and amplitude domain results.

Automatic DSP/Room Correction systems are powerful tools but they are not all created equal. The top-line units are considerably more advanced than mid-line units. I would not use my experience with a mid-line system to suggest the capabilities of the current SOTA technology.

One can easily argue that some of the large, immersive sound field is a result of the room/speaker interaction. Our experience with advanced DSP/Room Correction shows us that if the recording has spacial information (large, immersive sound field, depth, height) then a properly corrected system reproduces it. It does not embellish recordings that do not has spacial ques. Systems without RC can be setup to embellish spacial effects. I am not suggesting either is right or wrong. What you enjoy the most is what is right for you.

Read what a few reviewers said about our full DSP/RC system at Capital Audiofest 2021. The system was all tube electronics (except for the DSP unit) and vinyl source only (no digital files).

Mike

erik_squires OP
15,824 posts
 

It’s good to hear from someone who, at least, is open minded about DSP/Room Correction.

Hi Mike! @arion

I use it all the time. My main system uses Roon EQ and my HT relies on it for well, everything.

To be clear, I am not bemoaning DSP or digital equalization. Rather I had hoped that, specifically for home theater, the automatic speaker setup and EQ had become much more refined in creating a seamless 5 speaker sound field. Previously when hand-tuning my 5.1 system I achieved Atmos level immersion by hand calibration and the use of a pair of mini DSP units. Listening to Master and Commander would make you seasick and Hateful 8 had you dodging bullets.

I’m definitely not there with the Anthem Genesis tools yet. I fear this will take me some level of experimentation with outboard amps and re-introducing miniDSP to the mix.

arion's avatar
arion
156 posts
 

Erik,

I understand what you are saying. AutoRC doesn't do all and doesn't take into account a few things like personal preferences and an individual's hearing. We always tweak the system's auto-optimization. There are many manual settings to play with and it did take a while to understand what's best for our drivers.

One area were the system does a stunning job is with time domain issues. There is a clarity, naturalness and relaxed quality when the arrival time at the listening position throughout the entire range is spot on. The front end is not in the optimization and can heavily influence the outcome.

Mike

erik_squires OP
15,824 posts
 

One area were the system does a stunning job is with time domain issues.

@arion 

I've noticed this too.  I use a test DVD from Dayton to set the delay precisely across my speakers and it's a big difference. I have to say though, with the low frequency extension of your towers you hardly have the same crossover or phase problems most multi-way speaker makers have.  You have it easy. 😁

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