A couple of exceptions on Toto IV. Africa and I Won't Hold You Back are delayed 8ms. The rest of the tracks are 4ms.
DIGITAL At Least a Dozen 2002/2003 Elliot Scheiner 5.1 Mixes Have a LFE Issue (info/list/fixes inside)
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jimfisheye
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8ms is 3840 samples at 48k (double that at 96k).
That's in the ballpark for the round trip latency of an older circa early 2000's Protools DAW system. (No one did low latency back then. You'd set Protools as high as it would go and live with it still not being very stable!) That would be a largish latency for a plugin. I'd be surprised at that for just an eq plugin - even from back then and even some "boutique" example. 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!
That's in the ballpark for the round trip latency of an older circa early 2000's Protools DAW system. (No one did low latency back then. You'd set Protools as high as it would go and live with it still not being very stable!) That would be a largish latency for a plugin. I'd be surprised at that for just an eq plugin - even from back then and even some "boutique" example. 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!
Yes.
I didn't anticipate that the LFE delay would vary from track to track, so I didn't check the delay on every track - usually only 1-2 tracks per album. If other people like can pitch in and check every track of an album like @Cheezmo has, it'll help get this figured out much more quickly. I'll update the table in post #1 as more results come in.
There definitely is merit in the idea of creating either a database, thread, or forum section for discs that need "fixing" - I was actually discussing this with @HomerJAU in private, the idea of adding this kind of functionality to MMH, where there'd be a dropdown list of titles, and you'd just pick your album and it would apply all the fixes necessary. More on that as it develops..
There definitely is merit in the idea of creating either a database, thread, or forum section for discs that need "fixing" - I was actually discussing this with @HomerJAU in private, the idea of adding this kind of functionality to MMH, where there'd be a dropdown list of titles, and you'd just pick your album and it would apply all the fixes necessary. More on that as it develops..
Yes to the LFE? Or all channels?
This was Dave’s great idea! This can definitely be done and I’m happy to implement this in MMH. BUT:
First we need to collect the data:
Title (Artist - Album)
Release format (SACD, DVDA, BDA, Other)
Track(s) with Error (All or Track Nos (a list)
Error Type (Channel Phase Inversion or Delay, for Delay a correction value (ms)
I've been away from my PC for a while, but checking in on this thread from time to time, and am astonished at the work Dave, Garry and the rest of you all have done. Great job!
I am going to dive in myself and check out some files, but this is exactly the kind of thing that I'd always hoped would come of the community of QQ. It's fun to post funny pictures and let everyone in on the excitement of a new release being shipped and waiting for it to arrive, but that's all of the moment.
This is the kind of stuff that forums are built on. And that "Fix the Mix" suggestion for a forum section is a great idea. I would do it in a minute, but I can't do that anymore....
But I will bring it up to Angie if Garry or Tim haven't already.
I am going to dive in myself and check out some files, but this is exactly the kind of thing that I'd always hoped would come of the community of QQ. It's fun to post funny pictures and let everyone in on the excitement of a new release being shipped and waiting for it to arrive, but that's all of the moment.
This is the kind of stuff that forums are built on. And that "Fix the Mix" suggestion for a forum section is a great idea. I would do it in a minute, but I can't do that anymore....
But I will bring it up to Angie if Garry or Tim haven't already.
Too early in the morning here... Yes to All channels except LFE
MMH can only add +ve Delay, so to bring the LFE forward you actually need to delay all the others and leave the LFE alone. See this post:
https://www.quadraphonicquad.com/fo...-for-music-videos-mch-audio.22693/post-548566
Even if they were listening to a mix that included this LFE issue, I'm sure they were doing so on a system with 5 (extremely) full-range speakers and no bass management, so the effect would have been much less pronounced.
The real "bug" here is when you introduce bass management, and low frequencies from the main speakers are redirected to the subwoofer and mixed with the "mis-timed" LFE track. Then you get serious phase cancellation issues and loss of bass that is definitely unintended. It's my feeling that audio engineer worth his salt would knowingly send out a mix that induces phase issues that the ones I've highlighted to - if you want less bass in a mix, you mix it that way, you don't send out the main channels to have a tug-of-war with the LFE to accomplish your mission.
jefe1
2K Club - QQ Super Nova
Thank you Steelydave and all for this
I fall in Marpows category 1. I just buy a disc and play it. It infuriates me how many errors there seem to be in so many surround discs and why they weren't tested properly by the professionals who were paid to produce them.
I use full range speakers with no bass management and no subwoofer so far. But someday I may migrate to a different system will half of my surround discs start sounding like shit?
A good idea to make a sticky thread for the defects and fixes.
I know this is a first world problem in the scheme of things.
I fall in Marpows category 1. I just buy a disc and play it. It infuriates me how many errors there seem to be in so many surround discs and why they weren't tested properly by the professionals who were paid to produce them.
I use full range speakers with no bass management and no subwoofer so far. But someday I may migrate to a different system will half of my surround discs start sounding like shit?
A good idea to make a sticky thread for the defects and fixes.
I know this is a first world problem in the scheme of things.
Any evidence that the LFE delay varies during a song/track?
Kirk Bayne
Kirk Bayne
So here is a snippet from "Pretty Woman", from the Roy Orbison DVD-AUDIO (Yes, I have that and the SACD, so sue me)
Am I seeing that delay? I am not really sure, the others look more cut and dry
Am I seeing that delay? I am not really sure, the others look more cut and dry
Thought I'd check the DVD-A of Gaucho:
1: not sure if the center or the LFE (or none) that's off on this one
2: I listened just to the center at this point in the song, and it appears to be mostly bass.
3: I'm not sure how all Low Pass Filtering works, but I included Spectograms of the song Babylon Sisters to see what it looks like, I know if I utilize LPF in Audacity it just gives you specific set Roll-off db per octave and looks crude to me in application. Also applied to center channel as an example at 20K @48db in the third pic.
*Yes, we need a section of the forum to dive deeper into this.
If none of this seems correct or applicable, please delete!
1: not sure if the center or the LFE (or none) that's off on this one
2: I listened just to the center at this point in the song, and it appears to be mostly bass.
3: I'm not sure how all Low Pass Filtering works, but I included Spectograms of the song Babylon Sisters to see what it looks like, I know if I utilize LPF in Audacity it just gives you specific set Roll-off db per octave and looks crude to me in application. Also applied to center channel as an example at 20K @48db in the third pic.
*Yes, we need a section of the forum to dive deeper into this.
If none of this seems correct or applicable, please delete!
Just eyeballing it, it looks ok to me, but I'm not totally sure. I had this problem with Layla and A Night at the Opera, these "classic rock" types of albums don't have a lot of heavy low-bass transients in the LFE that would present as a 'big squiggle' in a waveform readout that makes it easy to determine.
If you can send me this track as a FLAC via WeTransfer or something I can check it with my phase correlation meter and we can be sure - feel free to PM me a WeTransfer link or something.
While it is good to know the discs and tracks that this problem is on. Once I find out that the LFE on a 5.1 mix contains bass that is low-pass filtered (upmixed) from the other channels, and not mixed that way from the multis, I am inclined to keep that channel turned down or off. Sub is off 90% of the time anyway.
Thought I'd check the DVD-A of Gaucho:
1: not sure if the center or the LFE (or none) that's off on this one
2: I listened just to the center at this point in the song, and it appears to be mostly bass.
3: I'm not sure how all Low Pass Filtering works, but I included Spectograms of the song Babylon Sisters to see what it looks like, I know if I utilize LPF in Audacity it just gives you specific set Roll-off db per octave and looks crude to me in application. Also applied to center channel as an example at 20K @48db in the third pic.
*Yes, we need a section of the forum to dive deeper into this.
If none of this seems correct or applicable, please delete!
View attachment 63977
Just as with the SACD, this one looks fine to me - you can see the waveforms in the full-range front channels have slightly more attack (the front of the "hill" is steeper) but that's presumably just because they have more of the treble/midrange frequencies present from the instruments making the sound, ie the head of the kick drum pedal striking the kick drum skin, and the bass guitar pick (or fingers) striking the strings.
Angie has created a "Fix the Mix" forum.
Maybe we should move this thing over there to christen the place!
Maybe we should move this thing over there to christen the place!
I just finished a pass through the REM DVD-Audios.
7ms for Automatic for the People, Green, Out of Time, and Up
Check out the rear channels on Airportman on Up, both obviously delayed different amounts, but I suspect that was intentional for effect.
4ms for Reveal
New Adventures in Hi-Fi is tough to call. Maybe 2ms, maybe close enough to not worry about?
7ms for Automatic for the People, Green, Out of Time, and Up
Check out the rear channels on Airportman on Up, both obviously delayed different amounts, but I suspect that was intentional for effect.
4ms for Reveal
New Adventures in Hi-Fi is tough to call. Maybe 2ms, maybe close enough to not worry about?
BTW its worth remembering that 10ms is only a single cycle of a 100Hz signal.
I think its fantastic finding out about mistakes and getting the opportunity to fix them. For me, though, the vast majority of Scheiner mixes sound amazing as is, so it’s unlikely I would do any work to “fix” them. But for those few instances where something sounds amiss, thank you to all who post solutions 
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