let us return to the wonderful world of LFE....
What happens when a release is initially DTS 96/24, but later rereleased as SACD? The Genesis catalog, for example.
Here's what happens with the LFE (for 'Squonk'...lots of bass frequencies on that one*). This is a linear plot of the averaged level (Y-axis) at each frequency (X-axis), displaying the part up to 400 Hz, at which point the SACD LFE average level is -100dB (let's call that inaudible). The lines start to diverge significantly at 120Hz, the SACD having higher level content from there on. A steep rolloff of LFE in DTS and Dolby Digital after 120 Hz is standard for those formats (this plot shows an approximate 50dB/octave drop after 120 Hz in the DTS signal vs 30db in the SACD).
Here is the Center channel, for comparison (displaying the whole audible spectrum). The two lines are essentially the same. The ~+4dB in DTS is consistent over the range, I can't explain where it comes from, but it amounts to a simple level mismatch (which in a blind but nonlevel matched comparison could well lead to the DTS being *preferred* over the SACD
) I *predict* that the same holds for the L/R and surround channels too.
What does this mean in practice? Short answer is, often nothing, but it *could* make an audible difference if you use a subwoofer...depending. It could make even
more of a difference if you
don't use a subwoofer....depending.
A. Consider the 'choke points' for LFE output., in a system with a subwoofer:
(1) the 'LPF for LFE' of the AVR -- the low pass filter applied to LFE content alone. Here's what one of my Denons offers:
LPF for LFE: Set LFE signal playback range. Set this when you want to change the playback frequency (low pass filter point) of the subwoofer.
80 Hz / 90 Hz / 100 Hz / 110 Hz / 120 Hz / 150 Hz /200 Hz / 250 Hz (Default : 120 Hz).
(2) the LPF ('crossover') of the subwoofer itself. This is both the adjustable electronic one built into the sub, and the actual usable FR of the 8/10/12/15-inch woofer + enclosure itself. Users of .1 systems are typically advised to either run the sub crossover as high as possible, or better yet turn it off if possible, so it doesn't pile on top of the upstream filters.
The upshot: for any settings or aggregate of these effects that allows >120Hz content to be output, there
might be audible subwoofer difference between these two releases. If there's a 120 Hz LPF choke at any point, the LFE difference should be inconsequential.
B. What about in a system WITHOUT a subwoofer, where LFE is routed to 'full range' mains?
Things could get
interesting... depending on if the AVR's LPF for LFE is set higher than 120 Hz. Look up there again: Denon permits a LPF setting up to 250 Hz... and notice there's a +30dB higher average level in the SACD vs DTS at that frequency. Admittedly it's still -80dB , quite low, but everything between 120 and 250Hz is louder than that. And this is all coming out of
loudspeakers, not a subwoofer. Unlike subs, speakers do not have a large intrinsic rolloff of their own at those frequencies.
The implications of this can be heard if you audition both LFEs 'raw', unfiltered, through headphones (standing in for 'full range' speakers). In this brief (fair use) clip from partway through the track, the first instance is the DTS LFE, the repeat is the SACD LFE. No level matching done (though even after level matched, they are distinct).
https://www.dropbox.com/scl/fi/pvc6...mple.wav?rlkey=nqyx1lcli710u5lxxev8ecu2t&dl=0
You'll hear somewhat more attack on the bass and kick in the SACD LFE, as well as a few bass notes high up the neck that are barely heard at all in the DTS LFE. This is because of those stronger SACD LFE frequencies above 120Hz
For the record, I don't think those >120 Hz frequencies belong in an LFE
at all, and certainly not any content above 250Hz! I think mixers lazily expect that the consumer will have a Dolby-compatible LPF in their system somewhere. But if you don't, be aware that you could hear a difference, depending on how your system is set up. 'System' means gear + room, btw.
And please NB that the LFE rolloff in DD and DTS is an industry *choice*, it
has nothing to do with them being lossy formats! You can see from the Center comparison that there's no need to be hysterical about 'lossy' (and yes, DTS 96/24 is still 'lossy') .
* Method notes: both versions were ripped from discs; the SACD rip was converted to PCM at 96000 kHz/24 bits to match the format of the decoded DTS 96/24. Frequency analysis was in Audition, using a Blackman-Harris FFT of ~65,000 bins. FA data was plotted in Excel.
Agreed you did show there is some content recorded to the LFE that is above 120hz. 99% of us won’t hear it. I don’t have the equipment or the wherewithal to do the experiments you did so thank you sincerely for that. 
