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The Bass EQ for Movies Thread

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19 hours ago, maxmercy said:

About 7 iterations to get this one right, as headroom was at a premium.  Turns out my first guess was closest to my final solution.  As I expected, <10Hz is highpassed away, only able to be brought back by ever increasing negative gains before BEQ.

Tentative LFE Solution:

Gain -7dB

Low Shelf 18Hz Q=0.707 +5.25dB

Low Shelf 18Hz Q=0.707 +5.25dB

Low Shelf 18Hz Q=0.707 +5.25dB

 

SME, if you can input that into your incredible DSP, I'd be interested in what you think of the solution.

Wow, thanks!  I didn't expect to see something come together so quickly.  I will try to give it a try tomorrow.  I actually haven't seen the movie before, and I don't want to watch it all the way through twice in one week.  So I'll probably try out the first 15 minutes or so.  That ought to be enough to get some good action scenes as well as some music.

I see you mentioning headroom here.  Are you saying that even with "-7" gain, the boosts are enough to push the levels on each track up to near full-scale?  So if played back so that the mids and highs are at ref level, the LFE track alone would demand 122 dBZ RMS / 125 dBZ peak?  That seems a bit high,being that my recollection is that overall peaks tend to come in at ~125-127 dBZ when played with mids and highs are ref level.  I'm probably just confused here.  In any case, from looking at the individual channel traces, this looks like this is gonna be a bass power house, even for a BEQ film.  Would you agree?  Or does this look about typical?

8 hours ago, Ricci said:

John how much time does it take you to go through the process above?

 

33 minutes ago, 3ll3d00d said:

If the approach is based on a target curve which is based on other known good bass films then t seems like this should be amenable to automation, at least as a first cut anyway.

For example, create a minimum phase representation of the actual response and a target curve, load into MSO and create a configuration that has a load of adjustable Q shelf filters & some PEQ available to it then give it some time to work out what combination of filters produces the target response. 

 

I am also thinking a bit about automation here.  I think the tricky thing about using something like MSO to find filters is that we want to only make coarse shape adjustments.  The finer peaks and dips in the peak and/or average graphs should be retained because they arise from specific effects that are meant to have characteristic sounds.

At the same time, I have reason to believe that something like MSO should concentrate more on coarse aspects of frequency response.  Contrary to common intuition, lower Q resonances in frequency response are actually quite a bit more audible than higher Q resonances at the same level.  A lot of the reason for this is that high Q resonances manifest at longer time scales.  While they tend to ring for longer than low Q resonances, they also require the input to be sustained for a longer period time at or near the center frequency to store energy.   Most content is inherently wideband, consisting of either transients or noise.  Even sweep effects are change quite rapidly.  Those few effects that are sustained are likely to "miss" the high Q resonance most of the time.

Anyway, I may be wrong about this, but the most useful piece to automate would probably be the calculation of new PvAs for a given input, ideally in an interactive way, similar to how REWs EQ simulator works.  If one can manually configure filters and see the result immediately, then one can iterate very quickly to the desired shape.

That still may not be the most time consuming part though.  That might be the headroom check.  With the tools that are available, it is probably necessary to apply the filters and then analyze the peak levels of the entire track to ensure no clipping occurs where headroom is limited.  This part would probably take a long time even with automation.  With help from a clever algorithm it may be possible to reduce this substantially by keeping track of the parts of the track that are at risk of clipping and only analyzing the effects of those filters on those parts.  It would still have to be fairly sophisticated to ensure nothing gets missed, but I think it's something I could work out how to do.

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15 hours ago, Ricci said:

John how much time does it take you to go through the process above?

Anywhere from 4-12 hours per film, with about 1/2 that time just waiting for processing to happen as I think about how to do the next trial solution.  Pacific Rim took me several days.  That filter was steep and hard to correct.

It does get easier, though.  I have done around 50 or so films and 30 or so DTS/THX/Dolby trailers.

JSS

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I still have to do a headroom sanity check on the overall film, but I will. 

Only 4-5 films I have re-done have ended up with any >128dB effects when played back at 85dBRef (+7dB on the MV). 

rant/

Most films are VERY tolerant of BEQ, which has led me to believe that it is possible to have unclipped, dynamic, full-bandwidth presentations if someone takes the time to create a film soundtrack properly the first time.  We unfortunately have few examples of this.

So much of the problem is that  most exhibitors will not playback films at Reference; too many complaints of "it's too loud".  This sometimes forces mixers to mix films under reference, knowing their films will not be played back at Ref Level, esp for dialogue driven films. 

To get loudness under reference level, you have to compress/clip loud passages to keep dialogue loud and clear enough if you mix significantly under Ref.  What happens if a film mixed under reference is played back AT reference level?  LOUD/COMPRESSED/CLIPPED Hell. 

It can be even worse for HT 'home mixes' depending on the playback system and Ref Level it is mixed at.  Was it optimized for soundbar, TV speaker,s, HTIB, or decent HT setup playback?  

And let us not forget about 'Director's Intent'.  I'm talking to you, Chris Nolan, ever since 'The Dark Knight' (though I hold out hope for 'Dunkirk'), and you, Joseph Kosinski (who admitted to messing with 'Tron:Legacy's BD mix, and the clipped hell it was in every channel save for LFE).

But I also have to thank Joseph Kosinski.  Without Tron:Legacy's obvious clipping, I would have never tried to find out how to look for clipping in a soundtrack.

I am just glad we get some decent mixes every now and then.  Too many variables at play, and not many (if any) standards followed, with so many various powerful interests at play.

/rant

JSS 

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The headroom check reveals that the BEQ version of the film played back at +7dBRef (Equivalent dialogue reference), no instantaneous signal peak is higher than 125.4dB.  Largest 'extended' peak (125ms) is 118.6dB.

Comparison PvA coming later.

JSS

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On 08/11/2017 at 9:15 PM, SME said:

I am also thinking a bit about automation here.  I think the tricky thing about using something like MSO to find filters is that we want to only make coarse shape adjustments.  The finer peaks and dips in the peak and/or average graphs should be retained because they arise from specific effects that are meant to have characteristic sounds.

That still may not be the most time consuming part though.  That might be the headroom check.  

The reason I suggested using MSO is because you have complete control over the parameter range for each filter and also complete control over how many filters, and what type, it can use. Combine this with smoothing of the response if necessary and I would have thought you'd end up with a smooth filter shape.

re headroom, is it the summed result that is the concern? 

On 09/11/2017 at 4:13 AM, maxmercy said:

Anywhere from 4-12 hours per film, with about 1/2 that time just waiting for processing to happen as I think about how to do the next trial solution. 

that seems a long time to wait for processing, what are you using for that?

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12 hours ago, 3ll3d00d said:

The reason I suggested using MSO is because you have complete control over the parameter range for each filter and also complete control over how many filters, and what type, it can use. Combine this with smoothing of the response if necessary and I would have thought you'd end up with a smooth filter shape.

re headroom, is it the summed result that is the concern? 

that seems a long time to wait for processing, what are you using for that?

Yes, the summed result can sometimes be higher than a worst case scenario, when played back at Equivalent Reference.  I check for it anytime I do a BEQ.

I have not used MSO, but it sounds promising, at least for a good first guess.

My long processing times used to be MUCH longer until one of the forum members here helped me out.   I am limited on speed mainly by the current hard drive and memory.  I am not using a new machine by any means, but it works well, and can run some of the old cmd line programs I need to do what I do with the tracks.  I also do a lot in Audacity, and have had to modify several of the plugins to suit my purposes.  I'm sure there are better tools out there.

When I am doing BEQ, I generally run a trial solution while I do something else, then check the result later, so I really don't spend a lot of time waiting.

JSS

 

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I gave GOTG2 a shot, albeit only the first 20 minutes of the movie.  I think the BEQ does the job well.  There were plenty of big full-bandwidth effects in that time frame.  I didn't even bother to compare with the uncorrected version.  There's definitely quality content down there.  Not all effects are extended, but most of the big ones are properly weighty.  I think I even got some floor motion from single digits content.  There's a nice sustained effect with a strong fundamental, maybe around 16-20 Hz (?), that's very appropriate to the on-screen action.

The mid-bass came through real hot, which I believe to be an issue on my end with the new sub config.  The kick drum on the music tracks didn't have the right impact, which could be part of the reason for the shelving and/or notching around 30 Hz, but I don't want to judge it until I've got my mid-bass issue ironed out.

I plan to watch the full movie tomorrow with BEQ and will report back.  It should be a good time.  :)

 

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I give the GOTG2 BEQ a big thumbs up.    A good time was had by all.  :D

Before watching, I made some bass tweaks, mostly adding a dB or so above 120 Hz, which provided much needed control for the mid-bass (i.e. 50-120 Hz ish).  Alas, I still haven't worked out a systematic way to balance the bass every time I reconfigure things.  By ear and by feel seem to be the only reliable way to go, but I seem to forget how to associate what I hear and feel between calibration sessions.  I have read that audio engineers have the same problem as far as losing the ability to associate hearing to actual frequencies that need adjustment without continuous practice or retraining.

As for the BEQed movie, well, I played it with the 30 Hz notch corrected and see no reason to try without the correction.  Admittedly, a lot of the music in the movie doesn't have much kick.  That which does seemed to hit just fine on the full run through.

Other than the dialog, the sound was quite good with no obvious clipping.  The dialog seemed a bit too loud at times, and it was not tonally consistent.  Some passages were a bit bright.  Some were overly full.  It makes me think that they left the rest of the sound alone for the cinema mix, and they either didn't re-balance the dialog for the home mix or didn't do a home mix at all.

The bass was pretty epic though.  I thought the bass was pretty impressive in the first 20 minutes (and it is), but it's just a taste of what this movie delivers.  Unlike the first GOTG, which seemsedto hit a bit heavier at the beginning than later on, this one just kept getting crazier as the movie progressed.  The last 40 minutes or so was an earthshaking powerhouse.  I noticed a lot of ULF-heavy full-band transients.  I also noticed a lot of strong, mostly transient effects centered around 20 Hz or so.  That's not to say that the movie lacked mid-bass at all, but the 20 Hz centered stuff did seem to dominate the soundscape at times.  Even though the strong effects were mostly transient, a few scenes provided many such effects in rapid succession for an extended period of time.

I recall someone suggesting that movies get a "bass quantity" rating for those who want movies that deliver a lot of heavy bass effects vs. just a few big effects.  While it would be hard to systematically rate movies in this fashion, GOTG2 with BEQ would almost certainly be "5 stars" in such a category.  So if one is looking for a good bass walloping, it's hard to go wrong with GOTG2 BEQ.  :)

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I recently tightened down my latest system EQ config, including a complete overhaul of the surrounds that delivers stronger mid-bass and more bass overall.  It's nice and punchy for music, without compromising deep bass, where it does show up.  I did some testing with music mixed to mono and sent to the center and each surround to confirm that the mid-bass retained its punch on each channel.  :)  Over the last few days, I've been testing with movies.  The opening bits of GOTG2+BEQ are even better than when I watched it before.  The kick drum on the music tracks has life!

Tonight I watched "Star Wars: TFA" again with BEQ.  I tried with the full mid-bass boost in the BEQ, but backed the PEQ gains down to only +2 dB per channel and added about +0.75 dB @ and below 30 Hz .  With the full +4, the mid-bass boost overpowered and killed the deep bass, but it obviously lacked punch at only +0.  The extra +0.75 dB down low seemed to get things just right.  There is a great balance of shaking effect and lots of chest thump.  I can't guarantee these adjustments will do right for everyone else being that they are quite small.

In any case, the movie was a fun ride.  It was the first time my sister and her husband had heard my system since I got the new speakers and subs.  They were smiling pretty big when it was over.  Now we're all properly ruined before we go to see "The Last Jedi" at a cinema next weekend.  :P

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BEQ for Valerian and the city of a thousand planets:

LFE:

sfm 19Hz Q=2.2 gain=+10dB

LCR:

sfm 22Hz Q=2.2 gain=+16dB

The LCR drops off a cliff at around 45-50Hz, and trying to repair this to get it flat will only give unpredictable results, the filter suggested will only partially recover some bass below and slightly reduce the 50Hz bump.

LFE turned out quite well. There is not much bass in this movie (from looking at the signals), but this filter recovers just enough to improve the experience from something that has no low end into a quite balanced, full-range sound with much more impact. The experienced difference is huge.

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On 6/14/2017 at 3:22 PM, maxmercy said:

Big Hero 6 BEQ Solution:

 

Pre-Post:

 

post-20-0-40218600-1497475041.png

 

LFE Correction:

 

Gain: -7dB

Low Shelf 16Hz, Slope of 1, +6dB (6 filters for a total boost of 36dB)

 

 

LCRS Correction:

 

Gain: -7dB

Low Shelf 22Hz, Slope 1.5, +4.75dB (2 filters for total boost of 9.5dB)

Low Shelf 23Hz, Slope 1.5, +4.75dB (2 filters for total boost of 9.5dB)

Low Shelf 24Hz, Slope 1.5, +4.75dB (2 filters for total boost of 9.5dB)

Low Shelf 44Hz, Slope 0.5, +0.75dB

Low Shelf 46Hz, Slope 0.5, +0.75dB

Low Shelf 48Hz, Slope 0.5, +0.75dB

 

The film gains significant weight to large effects, and while improved significantly, is not a whole new experience, but what I believe to be an enhanced way to see the film.

 

JSS

post-20-0-40218600-1497475041_thumb.png

I finally got around to watching this one.  I originally thought I was going to show this movie to family, but other things happened instead.

I can understand a relative lack of enthusiasm for this BEQ.  There are plenty of effects that sound great with this BEQ, but the use of low-end bass is inconsistent in the film.  I suspect that I could tell this without the BEQ enabled, but the BEQ makes the inconsistency a lot more obvious.  My favorite big effects are in the flying scenes.  :)  Yet some other stuff that looks big on-screen hits with about the same impact as a rock giant in "The Hobbit".  The BEQ is still worth it though, for the effects that do have the bottom end.  Several of the music tracks also have excellent slam, and it seemed like the BEQ might have further enhanced the slam.

On that note, this soundtrack has some other issues.  I believe it is one of the earlier films that was done in Skywalker Sound's dedicated "home mix" room for Atmos.  This is one of those films that does not need cinema EQ correction.  However, the mid-range seems slightly pushed and uneven still.  It also sounds like they used some kind of dynamics processing that's poorly configured and applied lazily.  The dynamics are very inconsistent.  Some scenes hit real hard and others are underwhelming.  To make matters worse, much of the quiet dialog is overly loud, and then in loud scenes, the dialog seems pulled back.  It remains perfectly audible throughout, but the level inconsistency is noticeably distracting.  Presumably, the engineers who worked on the home mix for this one were still getting used to the room, the tools, and the process.  The latter releases from Disney and others, presumably done in that studio, get much better over time.

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