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

[LTW]

seen this?

There, the culprit is clearly an EQ plug-in.


This again makes the result depend on the mixer's monitoring setup.
More ideally, an 80 Hz 'transition' would be standard and required.

More ideally still: no LFE unless absolutely required by the original definition of LFE

To clarify, I wasn't using linear phase on the LFE EQ filter so it introduced delay. No idea if that is the issue on these official releases.

I've taken to doing what Steven Wilson does in my mixes, just have a full range signal in the LFE channel and let the sub take care of it. But I see that people use bass management which folds that signal back into their mains L/R (I had no idea this was a thing)?

 

[Mickb]

On this one the FL and FR are out of phase with C, LFE, RL and RR channels.

Fix that by either inverting FL and FR, or inverting C, LFE, RL, and RR first. Then measure the delay. (My personal opinion is that FL and FR are polarity-correct and the remaining 4 channels are inverted in the final mastering, based on the polarity of the initial transient attacks.)

The phase inversion is going to cause much more audible change than the LFE delay.

thanks! - is there a quick way to invert for all tracks, or do I need to do one at a time in Audacity?

 

[ssully]

To clarify, I wasn't using linear phase on the LFE EQ filter so it introduced delay. No idea if that is the issue on these official releases.

I've taken to doing what Steven Wilson does in my mixes, just have a full range signal in the LFE channel and let the sub take care of it. But I see that people use bass management which folds that signal back into their mains L/R (I had no idea this was a thing)?

It's a terrible idea. Better idea: just DON'T USE THE LFE.

 

[DuncanS]

To clarify, I wasn't using linear phase on the LFE EQ filter so it introduced delay. No idea if that is the issue on these official releases.

I've taken to doing what Steven Wilson does in my mixes, just have a full range signal in the LFE channel and let the sub take care of it. But I see that people use bass management which folds that signal back into their mains L/R (I had no idea this was a thing)?

I've a 5.0.4 Atmos System with 4x Monitor Audio Silver RS8s Floorstanders (which go down easily to 33Hz - can have a lot of room vibrating Bass!) and a matching Silver RS LCR Centre, with 4x B&W M-1s mounted at ceiling level in the corners of the room for the Heights. No LFE. So I'm not sure what my Denon AVC-X8500HA does but it 'knows' I have no Sub, but so far all sounds good.

 

[AYanguas]

I've a 5.0.4 Atmos System with 4x Monitor Audio Silver RS8s Floorstanders (which go down easily to 33Hz - can have a lot of room vibrating Bass!) and a matching Silver RS LCR Centre, with 4x B&W M-1s mounted at ceiling level in the corners of the room for the Heights. No LFE. So I'm not sure what my Denon AVC-X8500HA does but it 'knows' I have no Sub, but so far all sounds good.

LFE is not a speaker. LFE is a channel in a multichannel file. It may be silent, but it is still a channel. It may be missing, but then the file may have some compatibility issues with some equipment.

Normally, the LFE channel is directed to the special Speaker to play the bass: The Subwoofer.

I have my Denon AVC-X8500H configured without SUB (because it broke and I still haven't bought another one). I have confirmed that my Denon outputs the LFE channel content to four speakers: Both Fronts and both Side Surrounds. Of course, all speakers are defined as LARGE. Not checked the bass management of the SMALL speakers (Tops) to see if the low end of that bass management outputs also to those 4 speakers.

Now I get a more equalized bass around the whole room than when I had the SUB. I.e. some kind of having 4 SUBs in a square. Of course I cannot cranck up the bass so much as before.

 

[ssully]

I've a 5.0.4 Atmos System with 4x Monitor Audio Silver RS8s Floorstanders (which go down easily to 33Hz - can have a lot of room vibrating Bass!) and a matching Silver RS LCR Centre, with 4x B&W M-1s mounted at ceiling level in the corners of the room for the Heights. No LFE. So I'm not sure what my Denon AVC-X8500HA does but it 'knows' I have no Sub, but so far all sounds good.

Like many here, you have confused LFE with speaker. The LFE is a *channel*, like the (front) Left and Right channels of stereo audio mixes. If you play multichannel sources, there almost certainly IS LFE in there. The question is what your system is doing with it.

If the LFE channel exists in your source mix, and if it contains signal (sometimes it's empty), you might want your system to output it, no? To do that in a system without a subwoofer, the LFE contents must be mixed into some other channel(s) outputs, usually the good old Left and Right. That's a form of bass management. It's what your Denon is probably doing.

It might actually not be what you want though. Some mixers, like the genius Steven Wilson, occasionally put full range signal content into the LFE. Or, the LFE might be significantly out of phase with the other channels (which is the question this thread concerns). Or, the LFE content also already exists in other channels, essentially it's doubled.

Strange and hard to predict things could happen then.

 

[svtmike]

thanks! - is there a quick way to invert for all tracks, or do I need to do one at a time in Audacity?

You can select multiple tracks at once and then just run the Invert effect on all four at once. It's a very fast effect.

 

[ssully]

You can select multiple tracks at once and then just run the Invert effect on all four at once. It's a very fast effect.

There's also a delay of 8ms in the LFE.

All of the Sea Change issues were noted already at the top of this thread

 

[Mickb]

There's also a delay of 8ms in the LFE.

All of the Sea Change issues were noted already at the top of this thread

sorry, just to clarify, if I need to phase-invert FR & FL for ALL songs (eg Sea Change), can I only do this one song at a time, then save from Aud, & do the next, or is there a quicker / simpler method?

 

[svtmike]

sorry, just to clarify, if I need to phase-invert FR & FL for ALL songs (eg Sea Change), can I only do this one song at a time, then save from Aud, & do the next, or is there a quicker / simpler method?

One song at a time.

 

[jimfisheye]

Audacity is the free and simple DAW-like app. Not sure what all the limitations are... been a minute since I looked at it. Reaper DAW might look intimidating to a hobbyist but the license format and demo that only nags when it runs out are pretty friendly. (They have an honor system reduced hobbyist license price. Same full featured app. Windows and Linux versions too, it's not Mac only.)

You could simply select 100's of audio items and click a command. If you're stuck with a one file at a time app and have a lot to do, check it out. Stuff like flipping polarity or nudging audio around are mundane and quick.

You can easily do stuff like dial up alternate versions and A/B. Like when you want to evaluate a move. Determine if the polarity flip was correct, etc. It's a full multitrack DAW - a modern upgraded version of what Protools HD was trying to do back in the day.

 

[ssully]

Guys , using QQ's own HomerJAU's Music Media Helper, one can do inversions and delay corrections in batch mode, multiple files at once.

 

[Mickb]

Hi,
Would appreciate views on this track: Queenryche - Empire (5.1) DVD-A, the LFE looks to be delayed by 7-8ms, but seems to be aligned with centre & surrounds:

 

[Mark Anderson]

I checked my 2002 SACD of Beck-Sea Change for the LF/RF being out of phase to the other channels before I made any adjustments and am not seeing an issue. I checked two songs and all I can see is the LFE delay.

01 - Beck - The Golden Age

& 04 - Beck - Lonesome Tears

 

[svtmike]

Hi,
Would appreciate views on this track: Queenryche - Empire (5.1) DVD-A, the LFE looks to be delayed by 7-8ms, but seems to be aligned with centre & surrounds:

Here's how I would find it:

1) Select all tracks (CTRL-A)
2) Apply low-pass filter to all tracks (Effect --> EQ and Filters --> Low Pass Filter... . It's not important what settings you use, but it is important that the same settings be applied to all tracks so the filter gives you the same group delay on all of the tracks.
3) Amplify the LFE track (select the LFE, then Effect --> Volume and Compression --> Amplify...) so you can easily see the peaks. 9 dB should do the trick or just use the suggested values in the Amplify filter.
4) Select a time selection from the peak in the FL or FR channel to the corresponding peak in the LFE.

The time between the start of the selection and the end of the selection is the time offset of the LFE. Here's what it looks like using Stand from R.E.M.'s Green album. You can see the 7ms delay as reported in the table near the beginning of this thread.

No need to export or save these changes, you are just doing this temporarily to measure. If you want to undo, just hit CTRL-Z twice and you are back to your original tracks.

 

[svtmike]

If you want a macro to perform these steps, this one will do it:

SelectAll:
Low-passFilter:FREQUENCY="120" ROLLOFF="dB12"
SelectTracks:Mode="Set" Track="3" TrackCount="1"
Amplify:Ratio="3.9810717"
SelectAll:

One undo afterward will undo all steps of the macro.