Originally Posted by noah katz
I didn't see anything to change my opinion about the Lyngdorf videos claims that their solution has superior timing that delivers correct tight packets of energy (or whatever verbiage they used) .
They didn't address it at all in the papers, and one of their test systems was a standard subwoofer-against-wall/mains-away-from-walls configuration.
How do they deal with the delayed reflections from the mains?
If they did do something of that description, they could prove it w/o spilling their IP beans with before/after impulse response graphs.
True, this is not addressed, and my (probably naive) interpretation of the following is that RP mainly attempts to correct the amplitude response (but guided by the avg. power measurements as mentioned before):
"The smoothed filter target, Gsmooth(f), is a real valued function of frequency, i.e. zero phase at all frequencies. <snip>
Here it is important to note that a sound field is 3 dimensional, which means that the phase response changes differently as a function of position when moving in different directions from a listening position. It follows from this, that correcting the complete phase response only makes sense in one point, i.e. 1 dimensional. This is the reason why only the part of the phase response, which corresponds to the amplitude response, should be corrected, i.e. the minimum phase part. This is obtained by employing Homomorphic filtering of the smoothed filter target function performed in Cepstrum domain "
However, by my own measurement I do see quite significant changes (improvements) in the impulse response (as well as a shift in the timing of the initial rise in impulse response - not shown here). Not sure why, and just speculations on my part that RP might be doing something more... See attached "before (red) and after (green)" impulse response graphs of the combined output of front left main + front left sub based on a sweep from 10-500Hz (here I am using the 4 aux sub config, so only the left front corner sub is activated in this case).
It should be noted that my listening room is far from perfect, with some nasty room modes.
Perhaps it is time to stop posting speculations and graphs... apologies in advance and please ignore me if it is not interesting