DIGITAL At Least a Dozen 2002/2003 Elliot Scheiner 5.1 Mixes Have a LFE Issue (info/list/fixes inside)

[fthesoundguy]

I really don't have much to add to the discussion at this point, but I have to say that I need to go get a Blu-Ray drive and start ripping my music. I still love playing the discs but this seems like a big enough widespread problem to look into tightening up the low end a bit.

...Maybe these were run through an external analog unit? And only the Lfe track for a low pass. And the loopback latency of that system was never accounted for? That would do it!

It's all fun in theory!

This is what i was thinking when I was reading through all of this. Way easier to just throw the whole mix through something and create a LPF track. Back in the early 2000s, maybe there wasn't the ability to zoom in as far as we can do now to really take a look at these things. (I wasn't around for those early Pro Tools iterations)

 

[LuvMyQuad]

I really don't have much to add to the discussion at this point, but I have to say that I need to go get a Blu-Ray drive and start ripping my music. I still love playing the discs but this seems like a big enough widespread problem to look into tightening up the low end a bit.

I think that's an excellent idea. But Im not convinced yet that this LFE issue should be the tipping point for anybody. There are plenty of other good reasons to go discless

 

[fthesoundguy]

I think that's an excellent idea. But Im not convinced yet that this LFE issue should be the tipping point for anybody. There are plenty of other good reasons to go discless

Oh I know, I've been looking into it a little bit because I don't go want to lose all of my albums because the blu-ray decides to just rot. There's a reason I was only vinyl (and streaming for the car) before finding out about surround. Those wax discs will still be here in 50 years and I can't say the same for any CD based item.

 

[Hawkeye_Mo]

I've got the "Adjusted" mix by Brian May version of Queen's A Night At the Opera. Does that one not have the 6ms LFE delay issue? I can't tell from the waveform. Thanks!

 

[knifeman]

Seems like surround sound has had it's problems from the start. From Quad "confusion" to the format wars to screwed up expensive box set BD's, and now to back up in time, so to speak, and discover this. Wow for sure. Starting to wonder if these lfe problems contributed to my basically seldom using my sub, as I usually prefer the sound without it? Don't know, but I'll stay tuned for further info.
Good work, guys!

How true. I have neither the ability, nor the interest to be fixing things that should not need fixing. What bothers me, is that this seems to be slowly becoming accepted as the price of doing business, and that's ********. I can't imagine any other hobby where I can spend so much money on product that has so many niggling issues. Phase issues, timing issues, disc rot, etc., etc., etc. I said it before, but I can't imagine any industry having worse quality control than this one. I like to listen to the music I buy and know it's the best version out there, and not have to dissect it looking for problems to correct. The consumer should not be doing the label's work, but this is becoming the new normal.

 

[timothyemerson]

How true. I have neither the ability, nor the interest to be fixing things that should not need fixing. What bothers me, is that this seems to be slowly becoming accepted as the price of doing business, and that's ********. I can't imagine any other hobby where I can spend so much money on product that has so many niggling issues. Phase issues, timing issues, disc rot, etc., etc., etc. I said it before, but I can't imagine any industry having worse quality control than this one. I like to listen to the music I buy and know it's the best version out there, and not have to dissect it looking for problems to correct. The consumer should not be doing the label's work, but this is becoming the new normal.

I agree. Everyone seems to have a "fix it with a software update" attitude, even when it can't. Do it once, do it right I say (and do it now while you're at it!). Lucky these guys aren't building bridges.

 

[HomerJAU]

I doubt anyone could hear any difference even at 8ms. 1ms = approx 1ft at the speed of sound. Can any one tell if their LFE speaker has been moved by 4ft with respect to the other speakers? I'd suggest not.

Here's a capture from Beck Sea Change showing the 8ms delay. It almost looks like phase inversion!

 

[Mcallister]

Wow! So much fuller adjusting the 8ms LFE on Sea Change

 

[Cheezmo]

I don't think it is fair to call out Schiener. I'm finding these delays on almost everything I look at.

Alannis Morrisette - Under Rug Swept (DVD-Audio)
Alan Parsons - On Air (DTS CD), A Valid Path is OK
Alice Cooper - Billion Dollar Babies (DVD-Audio), Welcome to My Nightmare (DVD-Audio).
B.B. King - Reflections (SACD) 6ms.

As you can see I'm just starting on the A's. Most the delay varies track by track 0-8ms.

 

[Cheezmo]

B.B. King & Eric Clapton - Riding With the King 4ms

 

[Jim the Oldbie]

[ now playing: Jethro Tull, "Wond'ring Aloud ]

OK - just what the hell is going on here, anyway?

This delay has now been demonstrated in so many titles, I've started wondering if there aren't just some natural phenomena at work here, as DuncanS humbly submitted waaay back up the road in this thread.

As we know, the LFE channel, among other treatments, is (ostensibly) a low-pass filtered extract from the main program. I understand for the most part the way filters work, and the phase shift they produce. But something with which I still struggle is the concept of group delay. I've read all the technical explanations of what it is, and they seem to make sense enough, but I'm just not able to grok the overall effect for some reason. But Duncan's reminder has stuck with me throughout my reading of this developing saga, and has made me curiouser and curiouser. So I decided to make an LFE channel of my own, from scratch, to see the exact changes that occur to the timing of the waveform.

I wanted something with a nice big convenient bassy transient right at the start, so of course I went straight to "Morph the Cat." Starting with the stereo CD mix of course, I loaded it into Cool Edit. First step was to do a mono mix, so I'd be starting with 2 identical, time-aligned waveforms to play around with. After a quick zoom-in to verify this, I then ran an 80 Hz, 4-pole Butterworth filter (a typical LFE treatment, I should think) on the left channel only, to do a direct comparison. Here's what came out:

The full-range version is on top, the filtered version of that same waveform below. I've used the selection tool to measure the delay; it starts at a waveform peak on the full-range, and ends with the corresponding peak on the low-pass filtered version. Way down in the lower-right corner I've circled the length of the selection (delay), which is 6 milliseconds.

To satisfy my own curiosity I did another round, this time moving the cutoff to 120 Hz just to observe any changes. Here's that output:

This delay came in at 4 mS.

The 2 conclusions I'm drawing from this experiment are:

1. Allowing for rounding errors caused by the 1 mS resolution of the Cool Edit timeline, these figures line up just fine with Duncan's formula above.

2. These delays are in the general area of those being discovered by so many here, and I believe they account in large part for what we're seeing. We all know that the processing of the LFE channel can vary widely from one title to the next, from the ridiculous full-range examples to any number of unspecified LP filter treatments. There's certainly no standard being adhered to with this stuff. In my estimation, this would account for a lot of the variation in delay times being measured.

So for me, the question now becomes: Why do some titles NOT show this delay?? Perhaps they were processed in the digital domain, using FIR filters (which can be configured for no phase shift or group delay) as opposed to the more conventional IIR types, which are basically digital versions of classic analog filters, with all the attendant phase behavior? That's my guess at this point.

Any other thoughts or ideas gratefully received.

Finally - Thanks DUNCAN!

 

[steelydave]

My feeling is that sometime around 2004 (give or take) whatever the issue was that was causing this behaviour was resolved - either there was a switch from outboard gear to digital plugins that compensated for the delay, or they were always using plugins and there was a software upgrade that "fixed" the delay issue.

@Cheezmo is right, this issue is more widespread than just Scheiner's mixes - I just had a cursory glance through a bunch of my DVD-A and SACD rips, and I'd say that for stuff 2003 and earlier, it's about 50/50 correct/incorrect.

This includes the Jeff Beck Blow by Blow SACD - if you look at the thread about the AP remaster which fixed the polarity, you'll find someone saying that the LFE still shows out of phase, even though the waveforms "look correct" (ie they're vibrating the same direction as the main channels). This is what we can now see as the telltale sign of a delayed LFE track.

The fact that pretty much every 5.1 mix done since 2004 doesn't exhibit this LFE delay issue still leads me to strongly believe that it isn't what computer programmers would call "intended behaviour". Unless you happened to zoom way in on the waveforms (which I don't think most mixing/mastering engineers do, or did, because they have to trust their ears more than their eyes) or listened to the mix back with bass management on (so that low-frequency content from the main speakers was being routed into the subwoofer) I don't think you'd notice this kind of thing. Especially back then, labels were making zero money on this stuff (as we found out when it died a quick commercial death) so they probably weren't throwing a ton of money at it.

I think what I'll probably do eventually is create some new master threads eventually in this 'Fix the Mix' section with full lists of every DVD-A and every SACD with a 5.1 mix done during the major label era, and then we can just slowly separate the wheat from the chaff. It shouldn't be that big of a project because there weren't THAT many discs released back then, and then of those, only a percentage actually exhibit an issue with the LFE.

 

[Eclectic]

I can't imagine any other hobby where I can spend so much money on product that has so many niggling issues.

Buy a telescope It suffers from the same flaw (worse, in fact) and for the same reason. They're complex instruments, each owner configures theirs a bit differently, and there isn't enough economy of scale to foot the bill for software that "just works."

 

[Jim the Oldbie]

More random thoughts are floating to the surface.

For a bit there I was thinking that perhaps this was a non-issue. As others have mentioned, since the bass levels would be a subjective decision during the mixing/ mastering process, any issues caused by this delay would be accounted for during that process by listening, not looking. But now I understand that this thinking is not necessarily correct, as illustrated by Dave in this post above.

When I read the reports of increased fullness in the bass after correcting the delay, I'm reminded that the "more is better" effect is but one of many tricks our ears like to play on us, but that might not be the correct way to see it either.

Anyway - it does seem plausible to me that those of us listening to this stuff on bass-managed setups are not hearing it the way it was heard in the mixing & mastering studios. It follows that removing the various delays should bring us closer to the non-bass-managed sound the engineers were hearing & working with.

Ideally, it would seem that fixing this should yield an improvement in the general consistency of bass levels across the board with these titles; that would be great, right? But I suppose that's too much to hope for; too many other variables involved.

I think my own approach will be to start with the titles I've thought of as bass-shy (can't think of a specific example at the moment; just woke up and I'm out of coffee!! ), and see if this fix can bring them more in line with what I'd perceive as normal, then maybe work back from there. It'll be cool to find some sort of correlation between bass-shy titles and LFE delay, but I won't hold my breath on that.

 

[ssully]

Beck: Sea Change (BDA) waveform:

View attachment 63910

Issue 1: LFE not aligned
Issue 2: L & R phase inverted with C, LFE Ls & Rs

EDIT: LFE looks out of phase too but aligning with a 8ms shift forward puts the LFE in phase with C, Ls & Lr

This (bolded) kinda blows my mind because the Sea Change DVDA* is hardly one that I'd cite for lacking bass. I'm scared to think of what it will sound like when corrected

(Ditto the bass in Nightfly, though there it seems the only issue is the slightly misaligned LFE)

I also don't know if the cancellation due to <5ms in some cases of misalignment will typically be audible. Some in-room measurements would be interesting here.

*I'm assuming the BDA mix = the DVDA -- but I will check this.

 

[ssully]

That'd be really good. Like a separate tab or something? To have an issue/fix HQ would be cool. I have some of the titles listed as -

Neil Young - Harvest - Channel assignment errors on certain tracks

Has it ever been confirmed that these were really errors rather than choices? (I have compared 'fixed' versus 'unfixed' and I did not find it a slam-dunk)

 

[Cheezmo]

Has it ever been confirmed that these were really errors rather than choices? (I have compared 'fixed' versus 'unfixed' and I did not find it a slam-dunk)

I think Faith Hill - Cry is pretty good evidence. There is one track "One" where the LFE channel was not low pass filtered. It is the only one that does not have the delay. If it was intentional they would have introduced the delay to that track too?

 

[ssully]

I think Faith Hill - Cry is pretty good evidence. There is one track "One" where the LFE channel was not low pass filtered. It is the only one that does not have the delay. If it was intentional they would have introduced the delay to that track too?

I was referring only to Harvest

 

[ssully]

*I'm assuming the BDA mix = the DVDA -- but I will check this.

I just read on the new thread that the Sea Change DVDA has no issues...

I can confirm from my own investigation of the DVDA that the front vs read/LFE phase is correct on all the tracks....except maybe the last track (track 12). There's something odd going on with the rear channels on that one.

However, the LFE is still slightly misaligned on all of the DVDA tracks. By 9 ms.

Track 4


Track 12



(misaligned, not inverted, because the LFE transient consistently starts 9 ms after the same transient in the other channels)

 

[Cheezmo]

Speaking of Harvest I just finished looking at the Barclay James Harvest releases. The LFE is pretty weak on these so perhaps not worth the effort.

Everyone Is Everybody, Gone to Earth, Octoberon, and XII all pretty much have a straight 5ms LFE delay on all tracks.

Once Again is a mess. The Center and LFE channels are inverted, and the LFE channel is delayed 11 ms.