Originally Posted by Gsaraco
My calibration was a painstaking manual job done by a friend of mine, but it's actually a perfect time to wipe it all since I'm about to move anyway.
Although your friend could have used, externally, a multi-million dollar RTA
that would outclass the internal one and provide slightly higher resolution in its readout,
what your friend didn't have is the ability to set the extremely accurate, even superior to "parametric" equalizer built in to the Audyssey XT unit you have. All that he/she could have done is access the fairly crude graphic equalizer, manually, which is quite primitive in terms of what it can do and would have take hours to painstakingly adjust to a setting which is ultimately only a crude facsimile to the precision of the internal one can accomplished in just seconds, via a sophisticated computer which does a correction based on eight different room positions averaged together as one, rather than a single position which it keeps its fingers crossed is fairly similar, no matter where you sit in your room. [No offense to your friend, but manual EQ, via a graphic EQ, is passé in my mind now, due to the much more powerful room correction Audyssey XT, or even better XT32 based systems now offer.]
Unlike the way the audio industry worked a couple of decades ago where there was nearly full disclosure and transparency so third parties could analyze and critique audio manipulations, both in terms of how they worked and what they did, Audyssey (the company) keeps their cards close to their chest, hidden from our full view, and will only give us little hints as to how the process works but I have analyzed it from their literature and technical papers and I will now describe what I have deduced:
Their original and most primitive EQ system was called 2EQ, and believe it or not this is the only
EQ system where they have divulged the actual
number of control points: 2 [and that's only my guess from its name, by the way. They never literally spelled it out, mind you.] Two control points is sort of like saying "we can control the EQ from two frequency location only". Bass and treble knobs would be an example of a two point system, although I suspect their's was more sophisticated in that the inflection points were variable across the frequency range and could perhaps have various steepness of slope, technically called Q, making it what we would call "a two band, fully parametric equalizer".
MultEQ, their next system, appearing later, upped the ante: it doubled the number of control points, so it was analogous to what would be called a 4-band fully parametric EQ, plus it added a whopping 128 control point EQ just for the sub channel alone, whereas the first system didn't have any for the sub.
MultEQ XT, found in the SR7005 for example, has 16X the number of control points of the original system's 2, for a total of 32, making it effectively a 32 band fully parametric EQ [with differeing Q for the two sides?] and uses the same 128 point system dedicated to the sub.
MultEQ XT32 found on the newer top end units is better even still, but in my mind a 32 band, fully parametric, computer controlled, up to 8 room position averaging system should be more than enough for even a room with sever and numerous problems, but I digress.
I don't mean to brag folks, but to the best of my knowledge, what you have just read, above, is one of the most detailed explanations of their various systems to appear anywhere on the web. All they have ever admitted to is "This number of control points, we refuse to disclose, is 32X better (greater) than this other number we used to use on earlier systems, that we also refuse to disclose". That's like saying "Today's temperature is twice as hot as what the temperature was on February 1st". Tell me my dear friends, from that statement can you deduce the correct temperature of today? Or that of February 1st? In fact without knowing the scale, in this case probably degrees C, F, or K, but who knows, you don't even have a rough feel for the absolute value of the difference in degrees.
Feb. 1st could have been 2 degrees C and today it is 4 degrees C, for example, or maybe Feb 1st was 45 degrees F and today is 90 degrees F? Who knows? They are keeping us in the dark and I believe describe it as a "trade secret for better marketing purposes".
Source for all my data mentioned:http://www.audyssey.com/technologies/multeq/flavors
The SR7005's manual
EQ, the only one a human calibrator has access to, is much more rigid and less flexible, although in some rooms it may actually do quite well [it depends on the room's errors]. It is a 9 band graphic
EQ, not parametric, so these 9 control points are much less flexible in terms of what they can do because unlike a parametric EQ these are locked, fixed, to nine specific frequencies and can't be moved up or down to other frequencies, their available boosts or cuts must be symmetrical on both sides and have a rigid, specific steepness or slope (also called the Q, short for "Quality factor").