Originally Posted by KC-Technerd
This seems rather unusual to me. First I would suggest trying the Pure Direct listening mode, just as a test. It will bypass everything including MCACC settings, EQ, crossover, etc. If that restores the brightness or clarity that you are looking for, then it will be a matter of finding what settings are reducing the high frequency response. This could be due to various settings including X-Curve, THX Re-EQ, equalization, etc. If Pure Direct doesn't restore the high frequency response/clarity then I would consider the wiring to your speakers, as it can also affect high frequency response.
What source are you using (CD, DVD, Blu-ray, etc.) and how is it connected (HDMI, Optical, Analog RCA, etc.)? If I remember right the SC-1523-K is the same as an SC-75 minus the elite badging, so I wouldn't expect any significant difference between it and the SC-79 as far as high frequency response. My SC-77 has crystal clear high frequency reproduction.
I would recommend setting your crossover to 80, unless you have some compelling reason to believe that your satellite speakers are significantly better at reproducing the 50-80Hz range than your subwoofer is. This could clean up muddy bass (which could contribute to the perception of lack of clarity), plus allowing the receiver's amplifiers to better handle mid and high frequencies since it won't have to handle those lower frequencies. I don't think it's likely that this is the whole issue, nor that it will make a huge difference, but there is a chance that it may be a contributor.
With the exception of my TV (because it doesn't have ARC), everything I use is connected through HDMI. My music source is a media player loaded with FLAC files connected through HDMI. I have a Blu-Ray player that is connected through HDMI as well. I've tried a flash drive loaded with FLAC files in my Blu-Ray player and it still lacks that top end that I previously had.
With regards to wiring, my surround sound wiring is 12 gauge and from the wall outlets to the actual speakers are 10 gauge.
Here is something of note. Before purchasing the SC-79, I took my 1523 to my friend's house to test on their setup, and it was definitely very detailed, bright and sparkling. We were both extremely impressed with the sound and we wondered what the SC-79 would sound like, since it is the flagship. Both of us ended up picking up SC-79s after that.
My friend was unable to dial in the EQ and other settings on their setup and since I was the one that was able to dial in the settings on the 1523 on their setup, I gave it a try on the SC-79 on their setup, and it was the same sort of flatness and lack of brightness I experienced on my setup at home.
Now, to be 100% transparent here, we did order refurbished SC-79s and they function perfectly, but I wonder if they may be tuned differently from regular off the shelf SC-79 receivers.
Both of us had the same results with that lack of top end that we saw with the 1523.
I will give your suggestions a test to see if anything clears up on the top end.