OK, time to get a little more persuasive...
Hulkss points are all correct --- proper upmixing does not keep the original channels intact, even for music, as this inherently destabilizes the soundfield. To make matters worse, please groove on the following points:
1.) Dolby Pro Logic II's 'music' mode was actually designed for cars, events, showrooms and other environments that require upmixing to >2 speakers but do not provide a reliable center channel, or do not provide one at all. It was originally included in home-theater receivers because, as was previously noted, center-channel speakers used to be frequency-limited to dialog, making them completely unsuitable for music playback. This is no longer true, however --- even Polk's cheapest 5.1 set has a full-range center speaker frequency-matched to the mains.
2.) A surprising amount of music, particularly from the 70s to the early 80s, was intentionally mixed for LTRT matrices. That's right --- probably at least
some of your music (especially if it's a non-remastered CD from the 80s) is already encoded for surround sound. When played back through a proper LTRT circuit, you'll get full 5.1 audio with independent stereo surrounds. And it's a fully intentional effect, mixed and steered by the audio engineer. Some sources, such as Cluster's first album, are pretty astounding when properly decoded, almost comparable to discrete 5.1 audio. At one point, several sound sources are panned around you in 360-degrees with near-perfect channel separation. This, mind you, is from a 1971 recording
But guess what --- 'music mode' upmixers completely destroy this effect, precisely because they do not remove the phased frequencies from the original channels. In fact, audio that is steered to either the center
or the surrounds should be removed from the mains. For example, if you play the aforementioned Cluster sample through a music-mode upmixer, the sound sources do not pan around you at all; instead, they seem to move from directly to your left, to directly in front of you, to directly to your right, and back again.
3.) The performance of any speaker-driver is inversely proportional to the spectral density of its output. This is one (albeit a minor) reason why subwoofer-crossovers are used, but the principle applies for any set of frequencies. Simply adding frequencies to the center and surround does nothing to lessen the burden on the mains, but it does increase the amplitudinal load on the receiver, theoretically worsening its performance. Conversely, properly phasing-out frequencies and steering them to other channels keeps the power-draw the same (as no frequencies are being duplicated), and also very slightly lessens the load on the mains and very slightly improves their performance.
So upmixing with full channel-steering maintains any soundfield better (even for vanilla stereo sources), enables encoded surround-sound cues in some music, and even slightly improves overall system performance. But funnily enough, even Dolby Pro Logic II doesn't offer any good options for music listening --- the movie-mode adds a hardcoded 10ms delay to the rears and aggressively steers all dialog-frequencies to the center, making it unsuitable for music. DTS:NEO seems to steer as much information to the rears as possible (which I presume is why it wins so many A/B tests
), again making it unsuitable for 'unmolested' LTRT decoding. Pro Logic I, of course, only has mono surround. Foobar's 'freesurround' plugin is impressive, but has issues of its own (audible phase-artifacts and frequency-shifts).
If JRSS were to offer a properly-steered music mode (which is essentially just a movie-mode upmixer with no delay in the rears and no frequency-based center-steering), it would only make JRiver that much more
wicked awesome.And while we're on the subject of upmixing
, mono sources should be played back in the front left and front right channels, or in the front left / center / front right channels, but never just in the center channel by itself --- which is currently how JRSS processes mono. Again, a simple user-selectable option would be great.
