Headphones Are Not Stereo (the other LCR problem)

[Music] hi and welcome back i made a video about lcr mixing a while back and there were a couple of common types of responses some people seem to get angry as if i were criticizing their mixing skills i dealt with that in a follow-up video but another common response was who listens in mono these days actually you'd be surprised mono bluetooth speakers are quite popular i gather there is one thing we can perhaps safely conclude however people listening in mono probably don't care about audio fidelity they just want to hear the song that's why when i do my mono check my concern is that the song still holds up which usually just means that the vocal is still up front and properly supported by exciting stuff behind it but of course you're perfectly entitled to decide to simply not care about people who listen in mono it's your call at the end of the day [Music] however there is another problem with lcr mixing that's nothing to do with mono compatibility binaural compatibility because headphones and earbuds are not strictly speaking stereo with stereo playback both ears hear both speakers but you're right here here's the left channel slightly delayed and filtered by your head binaural playback by contrast pipes each channel directly into the corresponding ear and those phase differences you were hearing in stereo are gone now you can argue with me about semantics and say that the word stereo has just come to mean two audio channels and that to insist on calling headphones binaural is overly pedantic and you might have a point but my point is whatever you call it listening to those two signals via a spaced pair of speakers doesn't provide the same experience as piping each channel directly into each ear [Music] hard panning a signal for stereo playback is fine the sound will seem to come from that speaker just as if the musician were placed at that point in the room but hard panning a signal for binaural playback is a very different thing now we have a signal present in one ear that's simply not there at all in the other which is something that never really happens in real life it sounds a bit weird and unnatural so let's imagine we have an lcr mix in case you're in any doubt lcr in this context means an approach to mixing in which every element is either panned straight down the middle like the drums percussion and bass here [Music] or hard panned left or right like these guitar parts yes this is a guitar part let me know in the comments if you want me to show you how i created this effect [Music] let's assume that we're happy with this mix in stereo and also in mono either because we've checked it and it's fine or because we've decided not to care about mono but then you try it on headphones and it sucks of course sucks is a subjective judgment you might really like that unnatural hard pan sound in binaural and i can't argue with you if you do but personally i usually don't fortunately however there are some really easy ways to fix the problem and as a bonus these tricks might also give you a mix extra depth and space in stereo as well [Music] if we look at the mix with span it's easy to see that the hard panned elements have no low frequency content there's basically nothing below about 200 hertz in the side channel which shows up in orange here so when i enable this high pass filter on the master channel set to 150 hertz and only affecting the side channel we shouldn't hear any difference right now this is the point where i should probably tell you to plug in headphones or earbuds or cast a video onto a device with stereo speakers but i'm not going to do that the techniques i'm showing you here are really simple and easy to try out in your own mixes whatever daw you're using so if you want to watch this on a mono phone then have a go yourself when you're in your studio that's fine just be aware you literally won't be able to hear any of the differences i'm talking about okay so let's try toggling this high pass filter on and off then i can clearly hear a difference the space the parts are in seems to change when i switch in the filter can you hear that [Music] let's try it with just one of the hard panned elements and while watching the meters with the filter bypassed this part is only in the right channel and the left channel is silent [Music] but not so with the filter switched in [Music] now the signal is apparently no longer hard panned what's going on here let's go back to first principles if a signal is panned centrally so equal amounts in the left and right channels it will appear only in the mid channel after encoding to mid side and there will be nothing in the sides channel however if a signal is hard panned left then after encoding that signal will be equally present in the mid-inside channels and if a signal is panned hard right it will end up equal and opposite in the midden side channels while intuitively you might expect a hard pan signal to appear only in the sides channel in fact that's not the case stuff that's only in the side channel will disappear completely in mono and might seem like it's coming from somewhere behind you in stereo but hard panned means equal in the mid-inside channels or equal and opposite so hard pan signals are dramatically affected if you introduce phase differences between mid and side and of course this high pass filter is minimum phase so it's creating significant phase shift around the cutoff frequency this is why you do need to be a bit careful about routinely modeling the base of your mix with a side channel high pass filter as it can change your stereo image in this case with hard pan signals i tend to prefer the high-pass version especially on headphones but if you've already carefully crafted the stereo image with tasteful and carefully applied phase differences you might not want to mess all that up by slapping on a high pass filter without listening carefully to how it changes the sound if it doesn't improve matters but you still feel the need to reduce the level of the bass in the side channel you can just switch to linear phase mode now switching the filter in and out makes no audible difference at all [Music] however now we've established that phase differences will do interesting things to our stereo image we find we have lots of ways to exploit that let's try a simple one using a free plugin [Music] this is a simple utility delay plugin which seems to be aimed at tasks like manual time alignment for example you could measure the distance from your spot mics to your main array and switch the units to meters instead of milliseconds so you can input those measurements without having to convert manually considered as a delay effect it doesn't seem to offer many creative options it doesn't even offer any feedback but oh this is so wrong i'm going to switch the routing to the mid side preset and now any delay i dial in will only be applied to the mid channel and as we all know delay always means phase shift so how much delay do you think i should try one millisecond seems like a pretty conservative starting point right [Music] wow [Music] this might be the most profound difference from the smallest change that i've yet to discover with the delay switched in we almost completely lose any sense that the parts are panned left and right but the width has been replaced by a profound sense of depth instead introduced one milliseconds is way more than i'd usually use i'm more likely to go with a tenth of a millisecond maybe up to three tenths at most this still makes a really profound difference when listening in stereo [Music] but it adds depth without entirely removing the left to right placement of parts [Music] but you can go subtler too if you want adding a tiny amount like 200th of a millisecond will hardly make any difference when listening in stereo [Music] if you're really happy with your hard panned lcr mix in stereo you'll likely be just as happy with the 200th of a millisecond delay added to the mid channel but this still makes a noticeable difference to binaural playback that weird sense that the part you're hearing in your left ear is really tiny and actually inside your ear canal disappears and it suddenly seems to be coming from outside your head and as a bonus this really useful little trick is available in about three clicks from a free plugin that will run in any daw [Music] okay let's try another example this is slick eq gentleman's edition from tokyo dawn and variety of sound the feature we're interested in is this little button here which unfortunately isn't available in the free version but its bigger brother is not expensive and has other advantages as well but first of all let's set the stereo processing mode to sun which is just another way of saying mid channel only and let's try turning on this mysterious little option that's just as dramatic a difference as when i delayed the mid channel to my ears at least [Music] because this button enables a group delay for the low frequencies in other words it's delay again but this time more for the low frequencies than the high frequencies we can tune the effect with the frequency knob turning it right up kills the stereo effect just as completely as a full millisecond of overall delay but with a different kind of depth added instead tuning it lower is probably a safer bet in most cases though even all the way down that difference still seemed really significant to me [Music] a word of warning however running this on the full mix means we're also affecting the mid panned bass and percussion elements this kind of phase rotation effect can be strangely unpredictable sometimes it makes the low end sound better sometimes worse sometimes just different but sometimes you might not hear any difference at all it totally depends on the source material and the only way to find out is to try it in this case i have no objections to the effect on the midpand elements but if you do you have a couple of options perhaps the simplest is to switch the processing to the difference channel instead which is just another name for the side channel this creates just as much phase difference between mid and side as processing the mid channel instead but we're now rotating the phase of the different signal instead and the mid panned elements are totally unaffected [Music] of course this would also be possible with the simple delay as well simply reset the mid channel to zero then switch to the side and dial in the delay there instead phase shifting the sides instead has a very similar effect but it's different somehow and for reasons i don't entirely understand at the moment i always seem to prefer it when i futz with the mid channel phase instead so in that case you can simply stick your hardband elements in a subgroup without the drums and bass and screw around with the mid channel phase on that subgroup instead of the master [Music] okay last trick this is reaper flavored but you should be able to do most of it with free or stock plugins in any daw i've got a chain of three plugins the js mid-side encoder followed by a re-eq then a js mid-side decoder the re-eq is therefore processing the mid and side channels rather than left and right and actually in most cases that wouldn't make any difference but i'm also going to open up the pin connector and remove the routing for channel 2. now the eq is only processing the major channel so if i add an all-pass filter we're now shifting the phase of just the mid channel you'll probably want to turn on the phase display to see that phase shift displayed on the graph if i shift the phase of the low frequencies with a wide and gentle bandwidth we can get something similar to the effect i got from slick eq's phase rotation but if i shift the phase of the high frequencies instead this is more like delaying the mid channel by a tiny amount but of course this is reaper which means i can modulate these parameters [Music] let's have some random modulation of the frequency parameter and why not the bandwidth as well and now my hard panned elements are chasing each other around a three-dimensional space instead of just sitting there boring the hard panned [Music] [Music] people talk a lot about how to get their mixes sounding wide but honestly that's kind of easy way more impressive in my opinion to have a mix with depth that's a much more compelling and mesmerizing illusion at least to my ears and it turns out that's easy too that's all for now thanks for watching [Music] you

Channel: Dan Worrall

Views: 94,869

Rating: 4.9552789 out of 5

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Id: uZ9WQDojQt8

Length: 16min 10sec (970 seconds)

Published: Tue Aug 03 2021