Hi Dave, I'm a few months behind on this one as I'm getting caught up on your channel's backlog. So much good stuff. Long comment incoming! This is an excellent presentation with clear illustrations that point out the issues with improper LFE usage. These are very real concerns that WILL ruin a mix. I'm coming at this topic from a post production perspective where we've been dealing with LFE forever. The LFE send in the Pro Tools panner has always been problematic and misleading. It simply mults the signal, sends it to the LFE channel, and depends on the crossover in your hardware (sub, amp, whatever) to eliminate the frequencies that don't belong in the sub. What's worse is you now have the same signal duplicated in the mains and the sub causing the aforementioned phase and fold down issues. In post production, we solve the issue like this: 1. Make a mono LFE send / return (we make three, one for each stem DIA / FX / MX). 2. Insert a low pass filter on the LFE return track, usually set to 85Hz. 3. Insert Avid Pro Subharmonic (or equivalent) set 100% wet. This way, the sub / LFE channel is not getting a duplicate of the signal, only the artificially generated subharmonics. Adjust the frequency range of the subharmonic generator to taste (whatever works best with the song). 4. Insert a limiter to keep it from getting too crazy. 5. Route the return into a mono subpath going straight to the LFE channel in the Dolby bed. 6. When mixing, turn up the LFE send to taste to accentuate dramatic moments or spots where you want a little more rumble. I would never 'set and forget' the send level for an entire song - LFE stands for 'Low Frequency Effects' so it should only be used as a special effect. This way, you don't have the phase issues since the signal has been completely altered from the original, and you don't have the fold down issues because it was added as a special effect just for those lucky few that will hear it on a real system - you can lose it in the stereo fold down and no harm done. So, use the LFE, but use it correctly and only when there's an artistic reason behind the decision.
Great video!! This clarified some things about my system and how I currently have it set up. I just sent you an email about something very similar about bass management and phase. One of my favorite bands (The 1975) has an album that was released during Covid, and when I include the LFE for almost every song on said album, the low end is pretty much non-existent. When I solo the LFE, there is a lot of extra low end that isn't showing up when I have my bass management turned on. When I have BM turned off or I take out the LFE, it sounds tremendously better. For almost any other album by the band, it has been great Atmos mixes. Is this the result of a poor mix/translation?
So question, in a situation where you’re using your Sub as both Bass management (via interface crossover) and as LFE, does that have a chance to double the bass??
Good question. If bass management is properly setup, it should not double your bass. You could, however, intentionally double the bass if you send it to the LFE in addition to the bed or an object.
@@goingto11 I seeee so we should really mainly treat the LFE as like the little extra umph, but not the only destination of Bass frequencies! Does it make sense to have a separate sub dedicated for LFE then? Thanks for the answer! Subscribed!
Thanks. I think I’ll ignore the lfe in my next production. I’ve only done 4 released atmos tracks. I did some lfe experiments to see what Apple Music does. Discovered it depends upon the iOS and if the playback is an apple device or not.
For example. I had a version of a song that had a bass drop only in the Atmos version in the lfe channel. Played back on Apple Music on my out of date iOS ( at the time ) It played back on everything in binaural because indeed LFE was present and it sounded like a different binaural on everything. Then I updated my iOS a few months later wondering if things would change. Indeed they did. Now. On everything besides AirPods ( 3rd party devices via Bluetooth like car , non Apple headphones ext ) it’s the stereo fold down. Same phone and playback devices. Just an updated iOS.
Using proq3 in Linear Phase mode will solve this issue instantly.
Yup
Hi Dave, I'm a few months behind on this one as I'm getting caught up on your channel's backlog. So much good stuff. Long comment incoming! This is an excellent presentation with clear illustrations that point out the issues with improper LFE usage. These are very real concerns that WILL ruin a mix. I'm coming at this topic from a post production perspective where we've been dealing with LFE forever. The LFE send in the Pro Tools panner has always been problematic and misleading. It simply mults the signal, sends it to the LFE channel, and depends on the crossover in your hardware (sub, amp, whatever) to eliminate the frequencies that don't belong in the sub. What's worse is you now have the same signal duplicated in the mains and the sub causing the aforementioned phase and fold down issues. In post production, we solve the issue like this:
1. Make a mono LFE send / return (we make three, one for each stem DIA / FX / MX).
2. Insert a low pass filter on the LFE return track, usually set to 85Hz.
3. Insert Avid Pro Subharmonic (or equivalent) set 100% wet. This way, the sub / LFE channel is not getting a duplicate of the signal, only the artificially generated subharmonics. Adjust the frequency range of the subharmonic generator to taste (whatever works best with the song).
4. Insert a limiter to keep it from getting too crazy.
5. Route the return into a mono subpath going straight to the LFE channel in the Dolby bed.
6. When mixing, turn up the LFE send to taste to accentuate dramatic moments or spots where you want a little more rumble. I would never 'set and forget' the send level for an entire song - LFE stands for 'Low Frequency Effects' so it should only be used as a special effect.
This way, you don't have the phase issues since the signal has been completely altered from the original, and you don't have the fold down issues because it was added as a special effect just for those lucky few that will hear it on a real system - you can lose it in the stereo fold down and no harm done. So, use the LFE, but use it correctly and only when there's an artistic reason behind the decision.
These are great tips. I've pretty much been doing that with the LFE for a few months now.
Well done. More people need to understand this coming from stereo and just jumping into Atmos, having completely bypassed surround learning curves.
Thanks! I do like to use the LFE but yes, it's definitely adding low-end in the Apple Renderer. Cheers!
Great video!! This clarified some things about my system and how I currently have it set up. I just sent you an email about something very similar about bass management and phase. One of my favorite bands (The 1975) has an album that was released during Covid, and when I include the LFE for almost every song on said album, the low end is pretty much non-existent. When I solo the LFE, there is a lot of extra low end that isn't showing up when I have my bass management turned on. When I have BM turned off or I take out the LFE, it sounds tremendously better. For almost any other album by the band, it has been great Atmos mixes. Is this the result of a poor mix/translation?
My guess is it's related to a filter placed on the LFE channel during mixing, and then overuse of the LFE.
So question, in a situation where you’re using your Sub as both Bass management (via interface crossover) and as LFE, does that have a chance to double the bass??
Good question. If bass management is properly setup, it should not double your bass. You could, however, intentionally double the bass if you send it to the LFE in addition to the bed or an object.
@@goingto11 I seeee so we should really mainly treat the LFE as like the little extra umph, but not the only destination of Bass frequencies!
Does it make sense to have a separate sub dedicated for LFE then?
Thanks for the answer! Subscribed!
I would not use LFE as the exclusive deliverer of low frequency content. I use it to augment a little here and there. I use a separate send for it.
Thanks. I think I’ll ignore the lfe in my next production. I’ve only done 4 released atmos tracks. I did some lfe experiments to see what Apple Music does. Discovered it depends upon the iOS and if the playback is an apple device or not.
For example. I had a version of a song that had a bass drop only in the Atmos version in the lfe channel. Played back on Apple Music on my out of date iOS ( at the time ) It played back on everything in binaural because indeed LFE was present and it sounded like a different binaural on everything. Then I updated my iOS a few months later wondering if things would change. Indeed they did. Now. On everything besides AirPods ( 3rd party devices via Bluetooth like car , non Apple headphones ext ) it’s the stereo fold down. Same phone and playback devices. Just an updated iOS.
Apple's Spatial Audio is definitely a moving target.
I think the original was pulled. But I suspect the Apple Spatial Audio exaggerates it.
Anyone else think that Atmos binaural -> all settings off -> played through stereo speakers -> sounds better than the 2.0 re-render?
How much would it have been a difference by choosing an 24dB instead 12dB filter in the LFE high cut?
I'm not sure exactly, but it would definitely make a difference especially since I believe a 24 dB per octave filter will cause more phase shift.