Sanjay,

Yes, I'm familiar with the paper you linked to, and have read it when it was originally published. I must tell you that it reads much more like a marketing blurb than a white paper. Let's examine some key points...

1. The paper attempts to mislead by first mentioning that 'room equalisation' is accomplished by using a pink noise source. This is so that the impulse response used to generate the same FR graph can be differentiated as unique to MRC later on in the paper, IMO.

2. The mention of some pro sound people using a graphic equalizer to create an inverse curve in the input signal is simply the same ploy, as no one uses a graphic EQ to equalize a HT and most savvy folks know that PEQ can't 'fix' a room.

3. They say that inverse curve equalization is wrong because it:
a. 'aims to arrive at a flat response which will suck the life out of a room.'
b. 'a graphic EQ [an analog EQ] produces all kinds of undesirable effects...ringing and phase errors.' Still, they correctly mention here that 'DSP-modelled EQ [which everyone uses] can be designed to avoid these problems.'
c. And that using an analog graphic EQ makes it 'problematical to try to perfect a room's impulse response'.

4. Next, they mention that to cancel out a 10dB notch [in FR] requires 10 times the power, causing one to run out of amplifier power. This sort of info is certainly for the uninitiated.

5. They then admit that 'Indeed, EQ like this [inverse curve PEQ] only really works for one listening position.'

So, first they spend 2 pages telling us why room equalization doesn't work, then they casually admit that it works for the primary LP.

6. They go on to say that looking at room modes is a better approach. Well, if it ignores a 'peak at 50Hz', whether it's just a poorly designed subwoofer or a boundary gain issue, I wonder how it can be thought of as better?

7. We now discuss that MRC only concerns itself with low frequencies, again PEQ 101 for those who employ one.

8. Next, under 'Filtering and Resonance', we finally get to the fact that MRC is a parametric equalizer that identifies peaks and flattens them to a less peaky state:
'So the aim of our room correction system is to identify important low frequency room modes-and their Q- and construct notch filters to reduce excessive decay times due to resonance at those frequencies to something more like the overall decay time of the room.'

9. Now we read that the range is 15Hz-250Hz. What is the range of the SMS-1?

To keep this shorter than it will otherwise be, I'll just say that MRC is nothing more than a PEQ that uses measurements from multiple spots in the HT, then averages them into a single FR graph, which it smoothes and then fashions PEQ notch filters to attack the peaks from 15-250 Hz.

It doesn't address placement (room and boundary gain induced peaks), delay settings and variable phase control of the sub to realign phase (which also can correct peaks and dips), and it describes that it's designed to treat the average sized HT and to treat it such as to reduce it to below the average reverberation time.

As they admit in the paper: "Here it is important to understand that there is a 1 to 1 relationship between frequency domain and time domain, i.e. time domain does not include any additional information not already present in frequency domain."

They offer impulse response, frequency response and waterfall graphs, all of which are derived from the impulse response (clicks or chirps).

It's redeeming quality, IMHO is that it treats all channels, but 'white papers' that contain words like 'astonishing level of DSP capability' leave me wondering if I'm being educated or sold.

It seems to be the latest gadget for the upscale owner who typically throws the manual away and wants to push a button for setup, IMO.

Certainly the same tool gives different results depending on what you do with it, but, as your own illustration points out, a capable sculptor like Rodin will create a better result than the same tool driven by a computer program.

Bosso