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Resolved: the "LFE channel" should never be utilized on SACD/DVD-A. (1 Viewer)

Michael St. Clair

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And then there's the issue of the 10db difference between movie soundtracks and hi-res 5.1 music. I'm still a tad in the dark on this, but it appears we have two different encoding standards for the "LFE" channel, and this also seems to be causing problems (small? large?) with system calibration.
Calibrating/testing the DVD-S2300 with Avia for DVD-V audio and the Chesky disc for DVD-A audio did not show a subtantial difference in bass levels (Ratshack SPL meter). 10db is very substantial.

I'm still in the dark as well, but I thought I'd share that.

Has anybody with other players and the same test discs seen a 10db difference?
 

Michael St. Clair

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I haven't! Are you saying that someone finally got it right (and Yamaha, no less)?
Unless I have a tin ear, I think they did.

Myself, John-Miles, Robert George, and several other people don't seem to think that the sound quality is degraded on the S2300. I haven't seen one person at AVS criticize it for SACD bass management, but I have seen people there criticizing other SACD players for sound quality with BM.
 

LanceJ

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Maybe some studio sound guys think: "Lots of people have those small, hideaway satellite systems with subs so let's make sure we take advantage of a sub's ability to go down to 30 or 20Hz to make things sound right".

After reading about music production the past three years on forums like these, I am also getting the feeling other studio employees are not--ahem--real familiar with what The General Public owns or likes. Have you ever looked at a photo of some of a studio's 5.1 monitoring rigs? Many times I have seen an enormous professional subwoofer with a 15" driver and huge amp (not those digital types--I mean a normal analog one with a big ol' manly 12" X 8" heatsink & huge toroidal transformer). 20Hz is no big deal for these monsters!

And five FULL sized monitors from JBL or Genelec.

I don't mean to sound like a jerk but I get the feeling some engineers think that having a sub channel for music is "really bitchin" & that anyone who buys these 5.1 recordings is an audio hobbyist willing to deal with complicated sound systems. The Linkin Park dvd-audio is a good (bad??) example of this: the LFE channel contains very low & very powerful bass; the front mains contain low & powerful bass; and the center channel also carries low & powerful bass (bass so low it can easily overload a speaker w/a 6.5" woofer--I know because I tested this myself). It sounds great......on the right system.:frowning:

I guess I'm just kind of rambling about this but I wish the AES or some other highly regarded organization would step in, write up some rules for 5.1 production AND ENFORCE THEM. No more of this "free spirit" & rather selfish lack-of-standards crap. It is getting out of control IMO.

FYI: While I was looking up KRK, a studio monitor manufacturer (their home is in Huntington Beach CA--great surfing there!!) I stumbled on this article. Looks like surround music IS trying to be promoted.

LJ
 

Steve_AS

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Being a Pioneer 45A owner, I surely appreciate that BM is often handled poorly. Hardly ANY manufacturer gets it right. My player will NOT send the LFE to the mains in DVD-A when I have it set to no sub (don't know about SACD), and it also will not send bass from the mains to a sub when I have my mains set to small.
Mine sends DVD-A bass to the sub if the mains are set to small and the sub is set to ON, and the source is either stereo or 3/2.1 ch (the exception being the Chesky test track, which for for some reason has sub output regardless of whether the sub is set to ON or OFF). In addition, for SACD, it will route bass properly for 3/2 material (e.g., the surround group of Tubular Bells).
 

Lewis Besze

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And then there's the issue of the 10db difference between movie soundtracks and hi-res 5.1 music. I'm still a tad in the dark on this, but it appears we have two different encoding standards for the "LFE" channel, and this also seems to be causing problems (small? large?) with system calibration.
Large and smaal settings won't affect anything regarding the LFE,your sub will taxed more but that's besides the point.Also,the fact that DD/DTS employs a 10db boost[this is happens at the decoding stage by your receiver pre/pro which is normally calculated in already with test tones,like the Avia,which is why you calibrate to the same level on all channels],shouldn't affect your calibration on the 6ch input,especially if internal test tones were used.However just to be safe I would use the Chesky DVD-A tones for this pupose[6ch input] to just to be safe.
 

Alex Shk

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As far as the topic goes, I agree - the LFE channel should not be utilized for SACD/DVD-A. That is NOT the same thing as saying a subwoofer should not be utilized in a music system.

IIRC - subwoofers with internal crossovers for music systems were first introduced for home music systems in the 1970's. This was used to deliver deeper richer bass to people that had "bookshelf" sized speakers that generally didn't handle frequencies below 100hz (or thereabouts) very well. I have been using a subwoofer off and on for music listening since the early 80's.

The LFE channel, for theater/home theater usage, was designed to deliver the ultra low effects (like a 10 hz rumble) that made movie viewing more involving. For music - a discreet "effects" channel like this really isn't necessary.

However - that is not to say that music cannot contain, or benefit from ultra low frequencies. It may not require it as often, but there are instances where tones as low as 15db have been utilized on standard stereo discs (Telarc had a CD of Bach's organ works that had tones as low as 5db, IIRC). It seems more practical, that for music, full frequencies be delivered to all channels. The hardware (amplifier, receiver or player) should allow for adjustable crossovers for those people that utilize a sub. There should be no concern about "overdriving" the mains. This was never an issue prior to the home theater craze - it surely wasn't a concern of Telarcs when they released that stereo Bach CD.

I think that the discreet LFE channel should be retained for movies - that's what it was designed for. I know that if I had spent big bucks on a premium set of full range speakers only to find out that frequencies below 60hz were being "kicked out" because I have no subwoofer and the downmixing process eliminates that channel, I would be pissed.

I guess the other side of the coin is that those who have home-theater-in-a-box type systems, with those tiny satellite speakers, shouldn't use those sysytems for full range music. After all, isn't the issue about NOT putting full frequency to all channels just an accommodation to that segment of the public? And doesn't it seem a strange accommodation when we're talking high rez audio?
 

Jack Gilvey

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Interesting thread. So my Sony 775 SACD changer is almost certainly converting to PCM since I need to use its internal BM? Could I safely assume if I go with the "5-Channel Direct" mode that there's no conversion taking place?
 

Rich Malloy

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I think so, Jack... either "Multichannel Direct" or "Five Channel Direct", whatever it's called on your player (tne non-BM'd settings are called "multichannel direct" and "two channel direct" on my C555ES).
As far as the topic goes, I agree - the LFE channel should not be utilized for SACD/DVD-A. That is NOT the same thing as saying a subwoofer should not be utilized in a music system.
Exactly, Alex. I was considering asking to have the title of this thread changed to more accurately reflect this, but it seems most everyone understands despite my poor word choice! A better phrase might have been: "Resolved: an LFE Channel should never be encoded onto an SACD or DVD-A disc".
 

Rich Malloy

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The only problem here is that Tubular Bells isn't 5.1, it's 4.0 (no LFE OR center)!
True, but I for one don't consider that to be a "problem", at all; rather a better way of encoding many discs.

For example, I was listening to the remarkable Chesky recording of Ana Caram's "Blue Bossa" last night--no "LFE" and no center channel and positively gorgeous.

But I'm certainly not making a general case against encoding a center channel, as I am against encoding an "LFE" channel. Still, those discs I've heard with no center channel, or very limited center channel like "Dark Side of the Moon", are quite good indeed. And I've heard discs with a "hard center" for vocals, etc., that I also like very much.

Tough call on this one, but I'm mindful that many folks have severely compromised center channel speakers. My center speaker is timbre-matched to my mains and uses the same tweeter, but unlike my mains is a three-way, unported speaker that does in fact sound just a tad distinct (as I think all will to some degree, excepting the use of an identical speaker in the center position).
 

Steve_AS

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The only problem here is that Tubular Bells isn't 5.1, it's 4.0 (no LFE OR center)!
But it 'reads' as 3/2 (which equals '5.0, I suppose) -- according to my player, at least.

I have some DVD-As that are 4.0 (EMI classical reissues and the cHesky disc), so it's not as if the player can't detect true 2/2 ('4.0'). ONe difference is, the 45a can
do bass managment on the 3/2 SACd but not on the 2/2 DVD-A.

Are there any SACDs out there that read as 2/2 (4.0)?
 

Rich Malloy

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Steve, I believe all the Chesky discs are 4.0 with the option of going 5.0 if you wish to use their "height envelope channel". Again, use of this channel is optional, and so I believe that most/all of the Cheskys playback as 4.0 on most of our systems.

(I may well be wrong--it's kinda confusing.)
 

Steve_AS

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Steve, I believe all the Chesky discs are 4.0 with the option of going 5.0 if you wish to use their "height envelope channel". Again, use of this channel is optional, and so I believe that most/all of the Cheskys playback as 4.0 on most of our systems.

(I may well be wrong--it's kinda confusing.)
I don't have any Chesky musical releases, but the Chesky test disc I have doesn't behave like any other disc in my collection, so I agree ;>

(I didn't know Chesky was doing SACDs now)
 

Rich Malloy

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I've got two multichannel Chesky SACDs, Ana Caram's "BLUE BOSSA", and Carter, Cobb, Coleman and Stern's "4 Generations of Miles", both excellent and highly recommended. I've also got the stereo Chesky SACD of McCoy Tyner's "New York Reunion" (which our own Lee Scoggins did production work on), and that too is a primo sounding disc, though not entirely relevant to this discussion as it's not a multichannel release.
 

Ed St. Clair

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This reminds me of the folks who are against the center channel, as well!
So, with that & this "Manifesto", our 'beloved' six discrete HiRez multi-channels, now becomes four.
What a joke!
Why not just go back too Mono!
That will solve 'EVERYTHING'!:D
 

Rich Malloy

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This reminds me of the folks who are against the center channel, as well!
So, with that & this "Manifesto", our 'beloved' six discrete HiRez multi-channels, now becomes four.
What a joke!
Why not just go back too Mono!
That will solve 'EVERYTHING'!
Ed, you've totally missed the point.

No one is suggesting that you not use an "LFE" channel in your system if you wish, but the application of bass management should be entirely a function of your playback system, because only you, the individual user, knows the range and limits of your speakers.

Now, to be fair, there is a segment of the public that would not see this as positive (if they understood it), and that's the "home-theater-in-a-box" crowd. These folks have limited speakers and limited (or no) bass management capabilities for hi-res, multichannel sources (DVD-A/SACD). A disc that's encoded to redirect bass frequencies below the limits of their tiny cubes to their itty bass modules would be better tailored to their systems, but would be severely compromised, even handicapped on any real music system. A vast number of music-first sorts prefer not to use a sub at all in their systems, and others prefer to "low-pass" the signal, and nearly everyone has different ideal crossover frequencies for their various speakers. For example, I cross my center over at 80Hz, my rears at 60Hz, and run my mains full-range for multichannel music. I'm able to do this, even on discs encoded with a "LFE" channel, but only because of the "Bass Redirect" feature on my Outlaw ICBM-1.

What I'm saying is that every primary channel should receive a full-range signal, there should be no cutoff encoded on the disc (no "crossover" to the sub), and thus there should be no "LFE" channel encoded on the disc. Those who wish to use a sub can use the bass management features of their players, receivers, or the ICBM-1. While it's certainly true that not everyone is capable of bass management on hi-res sources (e.g., the "home-theater-in-a-box" crowd noted above, first and foremost), I'd nonetheless argue that we NOT cripple the software for playback on compromised, el cheapo systems that lack these capabilities.

Is that elitist? NO. There are no other music delivery formats that are crippled for playback on cheap systems, unless you count the hideous mastering of pop recordings over the past ten years. But for all the compression and over-maximization of levels, I don't believe they sound one whit better on either FM radio or the boombox, though I presume this is the desire. The point is, however, that an "LFE" channel has never been encoded onto any music formats, though many listeners have long used subwoofers. You don't need a dedicated "LFE" channel to use a sub. It's a different issue. What seems to be happening to SACD and DVD-A is an attempt to shoehorn one format (music) into another (home video) which itself is merely an approximation of another form of presentation (the theater).

As mentioned throughout this thread, there are good reasons why a "Low Frequency Effects" channel was created for home theater, as the subsonic rumblings in many films from the past decade or two extend to frequencies well below that of nearly every piece of music (with a nod to the lower pedals of the pipe organ, the canons in the 1812 Overture, etc.). I do understand why people on this forum might be inclined to seeing this from a "home theater perspective", but I hope you've got my point by now. I'm not saying you should't use a so-called "Low Effects Channel" when you listen to music on SACD and DVD-A. I'm saying the specifics of this "LFE" channel, the frequencies re-routed to it and from which speakers, shouldn't be dictated by the encoders, for they don't know your system and its capabilities, my system and its capabilities, or anyone else's. After all, our systems differ substantially, even the very best ones. The disc's encoders simply cannot take this into account and provide a "one-size-fits-all" solution that's not somehow suboptimal for the vast majority of users.
 

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