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SME

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SME last won the day on November 20

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  1. I'm not the least bit surprised that the resulting mono tracks look very similar, even for cases in which the results sound totally different. In fact, I would expect this to occur especially when people are using your app to create the BEQs visually as opposed to doing it completely blindly and by-ear.
  2. I agree with you in part, but I think the differences can be greater than you'd think. A lot will depend on the particular mix and also the particular playback system and possibly some subjective preference. In TLJ, the failure to recover ULF from the surrounds is a sin of omission, which is relatively minor. Yes, it does mean that a spaceship might lose its weightiness as it pans from the front, overhead and to the rear, but at least the sound is not worse than what you started with. I picked the surrounds in my example because the difference is quite dramatic on paper and is one that we could all agree would be very audible with those discrete surround effects. However the front LRC channels are another story. Even though they roll-off at a similar point, their shapes are still quite different from LFE. So an EQ solution that is optimized to the mono sum average (which is dominated by LFE), could introduce new humps or bumps into the front LRC that weren't there before. Here's where we *can disagree* about what's audible and what's not. Though arguing from personal experience, even quite small bumps can be audibly degrading. Much depends on shape and bandwidth of the feature, in addition to the level, and also ... Audibility of differences will depend on the playback system. Systems with substantial bass problems may not reveal degrading resonances as readily. (That's not a virtue as such systems also fail to reveal a lot of content.) For example, a BEQ filter applied to front LRC that increases ULF while adding a slight bump around 55 Hz may have a pronounced boom around that area in general, but on a system with a severe boomy room mode at 45 Hz, the problem at 55 Hz may be hardly noticed. The BEQ might be an unqualified improvement on this flawed system, but on a system with very clean bass response, the 55 Hz bump may be much more obvious and degrading. If you had to choose between full ULF extension and balanced response between the deep bass, mid-bass, and upper bass, which would you choose? Personally, I'll take the balanced response over the ULF extension any day. IMO, the ULF is the least important frequency range. I believe the notion that "[global] BEQ that gives 80-90% of the improvement" is overly optimistic, but I am also inclined to judge the soundtrack for what it will sound like on a revealing system vs. an "average" one. So practically speaking, a global BEQ may be an improvement for most people who choose to use it, even if it does degrade other aspects of the bass somewhat. And I do understand that most people who have EQ capability at all can only use it on the sub output. I agree many filtered tracks can be improved to an extent with a global BEQ and that it's worth doing even if an independent channels BEQ would sound better. But I'm skeptical that a global BEQ will always be better than nothing at all. Focusing only on ULF, a BEQed track will always seem to be an improvement, but if one considers the sound as a whole, BEQ that introduces new bass resonances in some of the channels could end up sounding worse than nothing at all. Again, a lot is going to depend on the playback system. When doing these BEQs (whether global or channel-independent), it's very important to listen to the results on a system that is as accurate and revealing as possible. (This is probably my biggest gripe with the AVSForum thread where it appears BEQs are being developed using all eyes and no ears.)
  3. Again I disagree, and I think you're missing something key here. For any effect that is mixed exclusively to the surround channels and that contains sub bass , the difference between an independent-channels BEQ and all-channels BEQ is whether or not it's filtered at 60-80 Hz. The all-channels BEQ does boost the low end of the surround channels, but nowhere enough to keep it from rolling off rapidly below 60-80 Hz. I don't think we disagree over whether "filtered at 60-80 Hz" is subtle or not. To repeat myself, the only real open question is how much of the bass within the sounds mixed to the surround channels was copied to the LFE channel. To answer that question requires comparing the tracks side-by-side to see what the mixers did. To repeat what I wrote above, the total shelf gain recommended by @maxmercy for TLJ was +48 dB and not +60 dB. The +60 dB for GotG which also recovers meaningful content. Either way, any attenuation of say 60 dB by a filter should not be enough to force the relevant content into the quantization noise floor unless the tracks are getting down-sampled to less than 24-bits (i.e. 16-bits, -96 dBFS quantization noise floor) somewhere between where the attenuating filters were applied in production and where the BEQ filters are applied on playback. I believe DTS HD and Dolby TrueHD are always 24-bit. The rest of the production chain was almost certainly using at least 24-bit precision (probably 32-bit or 64-bit float in the DAWs). Realize that 24-bit has a quantization noise floor of -144 dBFS. It's actually quite impressive that I can get away with the +60 dB boost for GotG being that the signal inputs to my processor are analog (unbalanced actually). The ULF noise floor of my unbalanced analog connections must be in the neighborhood of -100 dBFS. This is incorrect because it is outdated, on two accounts. The situation changed with immersive formats. First, as I explained in my above posts, Atmos for cinemas (and probably other immersive formats) introduced support for bass management to be used for surround and overhead channels with dedicated "surround subwoofers", preferably located at the sides or rear of the room. The Dolby specs *require* every screen, surround, and overhead channel to extend to 40 Hz, using bass management as necessary to meet this goal. I don't know how many dub stages use 40 Hz vs. 30 Hz subs for surrounds, being that the front channels are still run without subs (usually extending to 40 Hz on their own). Second, cinema Atmos is not compatible with the home Atmos. This means that *all* Atmos BD and UHD releases are dedicated home mixes or masters. This work is done in small rooms that mimic home theaters, and I expect all of them use bass management for the overheads and surrounds (and probably fronts too). The Atmos home format (or rather the equipment that implements it) does not support separate surround subs, so bass managed bass all goes to the one SUB channel, which will almost certainly extend to 30 Hz or below. Also keep in mind that sound design is a separate step from the mixing. Most sound design is being done in small room studios where capabilities (for better or worse) are very different from the dub stage. Some sound designers might even work using sealed subs and small enough rooms to get significant ULF. But even if they can't hear the ULF on the track, it's not fair to say that it wasn't part of the sound design. Whether the ULF was part of a recorded or synthesized effect, it originated as part of the design process. The only question is whether the designers/mixers/directors are able to hear what they've done.
  4. I assume the after is with the @maxmercy BEQ applied? Either way, I strongly disagree that the fact that the surrounds have lower average levels means their shape is not audibly important. Average level depends on short-term level, duration, and frequency of effects. Most action happens up front and in the center, so it's no surprise that the surrounds have much lower average levels than the fronts. Yes. However, without additional information we can't tell how the LFE channel was used. There's no guarantee that content that's mixed to one or more front/surround channels gets sent to LFE too. Many strategies are possible, and you can't really tell what was done by looking at either of the PvA curves. *Of course* there are distinct effects in the surrounds! Any sound that gets mixed to the surrounds that has bass will be affected by the filters applied to that channel during production and the BEQ filters applied during playback. Unless most of that bass was copied to or sent to the LFE channel, an independent channels BEQ will recover ULF in the surrounds that an all-channels BEQ can't. The result won't be subtle for the discrete surround (and overhead) effects with sub bass, especially given the ~60 Hz filter! I do agree that the post BEQ surround channel averages look odd, particularly below 30 Hz. Why do all the surround channel curves converge to one curve below there? I would not expect that to happen. The shape of the curves and lack of finer details is also unusual. It looks like it could be garbage. Maybe insufficient precision somewhere? Are you applying the 1st order high pass at 10 Hz? And is it working correctly?
  5. How would you define "extremely large"? It's a bit hard to tell from your pictures, but it looks like the green curve for least one surround channel levels out at around -72 dB (average) below 20 Hz. To get this content to about the same level as the stuff at 100 Hz (-33 dB) requires up to +39 dB of shelf. Here's the total shelf gain for each channel for the @maxmercy BEQ correction: LFE: +20 dB LCR: +18 dB SURR: +48 dB (!) Note that these also use 1st order high pass filters (f0=3.0 Hz for LCR+LFE and f0=10.0 Hz for SURR) to remove DC noise in the track. I'm pretty sure this BEQ has it covered. Is +48 dB really an extreme boost? I don't think so. One of my other favorite BEQs, which I just watched the other day is for Guardians of the Galaxy: LFE: +40.5 dB LCR: +20 dB SURR: +60 dB (!!) As a point of note: my processor is connected to the upstream via analog, so I do have to worry about the effect of boost on the analog noise floor. With the GotG BEQ applied and no sound playing, I get periodic spurts of noise that are enough to register on my Motu 16A display ("-48 dBFS") and to light up the "signal present" lights on my amp. That's probably only ~1W actually going to the subs, so no worry there. However unfortunately, even at that extremely low level the ULF output is enough to cause one of my living room windows to make ticking noises. GRR!!! Ignoring that though, the above GotG BEQ delivers very excellent sound.
  6. By "levels", are you referring to relative level of each channel in the PvA data? If so, I disagree with your argument, at least in general. A lot depends on how the mixers created the LFE channel content. For TLJ, It could be that that the bass under 60 Hz in the surround channels just gets thrown out rather than being sent to LFE. If that's the case, then a global BEQ will likely have little to no effect on the surrounds because the ULF boost will be well below the 60 Hz roll-off. To figure this out, I guess one would have to compare the tracks, looking for some place where an effect with bass plays on the surrounds only and then checking if any of that missing bottom end found its way into LFE. I'm curious if @maxmercy has any insight here. How much evidence is there of mixers splitting content between surrounds and LFE using HPF/LPF pairs? I'd bet there are many different strategies used for managing LFE and that for a great many cases, a separate-channels BEQ will be much better.
  7. SME

    Othorn - HT capable?

    Nice ideas here. I hope that XO processor works out for you. Definitely experiment with different settings. Measure and compare if you can and have the patience. Unless you're using real weak amps on the mid/high horns, you might seriously consider adjusting the passive circuit to attenuate things more. I don't know if that would be feasible in your case, but it could make a huge difference with regard to noise while also improving safety from faults (both for the drivers and your ears). Even if you listen real loud, I seriously doubt you need sensitivity that high. It may be fun to brag about, but practically speaking it's a nuisance with regard to noise and possible safety concerns in the event of a fault. My speakers have horns covering content above 850 Hz+ that are 108 dB sensitivity without passive electronics. I have a passive circuit to cut them by 6-10 dB over most their range and I've cut the output gains for them on my DSP an additional 6 dB, meaning that I probably hit like 50W peak before clipping in the DSP, most of which is sunk into the resistors of my passive circuit. My DSP interface has peak and average indicators for each channel so I can literally watch my headroom. I listen to plenty of stuff plenty loud, and it's rare for the peak level to exceed -10 dBFS. Only with a handful of cases do I see peaks up near the top. One example of some demanding treble (at least for my horns) is the hand-held phaser shoot-out in "Star Trek" (2009) when playing at a MV in which I probably hit peaks > 125 dB SPL (with help from the subs) in other scenes. Of course, with the kind of subs you're building, you may listen to stuff way louder than I do. But seriously, those kinds of levels are not going to be good for your hearing in the long-term. I can play a good dynamic multi-channel concert video at something like "+3 dB" vs. reference level (and a generous house curve on the bass), and it sounds wonderful without even a hint of strain! The sound is so clean, detailed, expansive, and powerful. And then after 5 minutes it stops and my ears will be slightly ringing and after a couple hours, my hearing will still be altered. That's hearing damage territory, and for me, that's *enough* headroom.
  8. I should be able to see that one soon and will give my feedback. I do hope it's not as bad as "Black Panther", which as I said sounded more compressed than analog TV to me. BP had a $200 million budget, and given that "sound is half the movie", there is no excuse for this. At this point, I don't really have a problem with studios pulling dynamics back a bit for home mixes. The mid-range emphasis that results when a cinema or dub-stage is calibrated to the X-curve target makes the sound smaller and whimpier. For a long time, I assumed that mixers compensated for the lack of bass and treble using EQ boost, but I was mostly wrong about that. I say "mostly" because I think some EQ does find its way in to a lot of tracks, but it's much less than would be needed to reverse the effect of the X-curve calibration. So even after EQ tweaks, the sound in the cinema is still lacking in bass and treble and seems small and whimpy. The mixers compensate another way: using the faders. The consequence is a mix with exaggerated macro-dynamics because the mixers are pushing up the levels of the big effects for more pop. There's a huge difference, however, between pulling dynamics back a bit for a more authentic "cinema-like" experience at home and crushing the mix to the dynamic range of a typical Internet pod cast. Also, I could be wrong but it sounds like BP just got shoved through an algorithm without any scene-by-scene consideration at all. I don't have a problem with automation being used as part of the process, but at the least there should be people going through the mix and making tweaks for different scenes. It took a lot of fader twiddling to get the cinema mix the way it was. It's ridiculous to assume that a simple algorithm can reverse all of that. The sad thing about all this is that most consumers don't complain. The industry thinks that means that it doesn't matter, but it does even if consumer don't complain. Most consumers don't notice the lack of dynamics. They don't notice the lack of emotional impact and lack of connection with the actors. They don't notice that the overall movie experience is less inspiring or that their motivation to purchase media in the future is diminished. And when the sales start to drop, will the industry recognize that quality matters even when the consumer isn't aware of it? Or will they just blame the loss of sales on pirates?
  9. FWIW, I liked TLJ as a film a lot more after the second watch. It's definitely flawed, but what SW film isn't? Yes! Because the channel architecture includes the LFE channel for extra bass headroom, any film mixer that wants to use LFE in the mix must effectively use some kind of bass management when creating it. Microphones and synthesizers don't tend to spit out separate LFE tracks, and I doubt the sound designers deliver content with separate LFE either. Even if they did, it wouldn't allow optimal budgeting of headroom in the mix, so basically it comes down to the mixer to figure out how to distribute the sub bass between the different channels of the mix. I'm sure many different strategies are employed including the wacky filtering schemes seen in TLJ and many other movies. I wouldn't be surprised if a lot of the bass that appears to have been filtered from the surrounds was simply re-routed to LFE instead. This is probably why almost every one of the BEQs developed by @maxmercy uses quite different filters on each channel, and why I believe this approach is usually necessary for good BEQ sound quality. Even then, it's probably not possible to fix everything. The bass management on the production side may be applying very different filters to sound that is redirected from each mains channel to LFE. For example with TLJ, it's possible that the 40-60 Hz part of the LFE channel contains a lot more bass that goes with sounds in the surround channels than screen channels, but below 40 Hz, it's a more even mix of screens and surrounds. So any adjustments made to LFE could have different effects on the surrounds vs. the mains. Lastly, we need to remind ourselves that bass management on playback systems has a lot of problems too. Probably very few systems out there have neutral sounding bass for sounds on all 7.1+ channels of a soundtrack because of sub crossover phase issues. The more savvy home theater people know to optimize sub delay for best sub crossover response, which makes a *huge* difference, but this is only possible on one channel (i.e. the center channel for movie optimization) or some weighted sum (i.e. left+right for music optimization). How many people here or anywhere have good response in the sub XO region on their surround and overhead channels? Yes, those channels do get used for bass, and they get used a lot more now because immersive formats for the cinema specify bass management for the surrounds. I personally have the capability to optimize bass management completely and separately for each mains channel and for LFE, which is itself optimized to blend best with simultaneous content in the center channel. IMO, this should be a minimum requirement for a "high performance" home theate, but it's not possible to do this with any standard home theater processors I know of (without spending 6 figures $ at least). I doubt very many "Atmos at home" production systems have that capability, which means they aren't hearing the bass right on their own soundtracks. (Sadly, I wouldn't be surprised if many of these don't even have the sub distance optimized for best center channel response.) At least Atmos in the cinema specifies that surround and overhead channels be bass managed to separate "surround subs" located closer to the back of the room, which probably helps a lot, but Atmos for home is still essentially a 7.1+ format.
  10. SME

    Ricci's Skhorn Subwoofer & Files

    While within their limits, amps are essentially voltage control devices, so the loads in parallel won't interact via an electrical path. There may still be mechanical interactions from shared air space or external proximity/boundary/acoustic loading effects but from an electrical standpoint, the two drivers don't "see" each other. In a series configuration however, it is possible for power to be transferred between the drivers unless they're exactly the same. Any electrical or mechanical differences between the two drivers may cause energy to flow between the two, which can complicate their behavior compared to systems with all drivers in parallel. It's also possible that this interaction could couple with another interaction (say acoustic or mechanical interaction due to proximity or shared air space) in a way that leads to a feedback loop that causes unstable behavior. In reality, the differences involved are probably too small for this to be a problem most of the time. However, I believe there are always opportunities for exceptions. Some manufacturers may be more consistent than others with regard to parameters that matter. Loading drivers into a tuned enclosure (especially one with higher pressures like a horn) could amplify certain problems. Running the drivers harder where non-linearity becomes a big factor is probably likely to accentuate such problems too. But this is all really just theoretical speculation. I have no idea if any of these effects are really strong enough to cause serious problems.
  11. Other movies watched recent: "Ghost in the Shell": I liked it a lot, and it had some cool mid-bass glitch effects and a very interesting score. The bass was OK otherwise, filtered in the 20s but not too aggressively. "Jumnaji": Worst bass I've heard in a while. It had some ULF, but it had a severe 30 Hz hump and almost no mid-bass. It was loud and boomy and had absolutely no punch or clarity and almost no tactile at all. For all the attention given to ULF, I think good mid-bass is more important. Without enough mid-bass in the track, the low stuff just sounds terrible. (Edit) "Ready: Player One" with BEQ: Bass movie of the year for me. Possibly my new favorite bass movie ever. Excellent full-bandwidth sound design. Very tactile throughout. You are *there*. I kind of miss the discussion here where we gave our subjective impressions of these tracks. Maybe all of that happens at AVSForum these days?
  12. So I watched "Black Panther" finally. I played the BD 7.1 at "-1" (!), and my Denon did not indicate any dialnorm compensation was applied. I have to agree that this soundtrack has serious deficiencies caused by excessive and/or mis-configured dynamics processing. It was bad. It seemed worse than the dynamics of old analog TV. Not only were macro-dynamics largely eliminated but the compressor attack seemed to act immediately and aggressively on transiently loud sounds such as gun shots. IMO, the consequences were wide and substantially degrading to the viewing experience. The experience was passive and uninvolving. The on-screen action and actors seemed trivial and insignificant. It wasn't just special effects that were harm but also the score, dialog, ambiance, etc. The scoring involving live acoustic instruments (vs. the pop / hip-hop style music) sounded completely unnatural and irritating to listen to because of the pumping effects. In one scene, dialog alternated between a few key characters and a large crowd, both of which were rendered equally loud but of course this made the crowd sound very whimpy, and the aggressive compression really muddied their voices together. It really broke the immersion. The acting seemed quite forced throughout the movie, but I could also tell that the dialog completely lacked the dynamics which may play a big part in conveying passion and emotion. The weird thing is that even if this aggressive compression was done on purpose, perhaps to optimize for hand-held devices in high noise environments, the level of the track was extremely low. I basically had to turn things up to cinema reference level to get sound that still wasn't that loud. That's a huge amount of gain as far as hand-helds go. On most if not all such devices, this track would be difficult to hear even with the volume at max. Oddly enough though, it had some decent bass in a few places, particularly in some of the quieter scenes where there wasn't as much mid/high frequency content to compete against. The tonal balance was actually quite nice, and I experienced a surprising amount of ULF with rather strong tactile effect. A lot of ULF just makes the windows rattle and maybe shakes the floor a bit, but this was felt quite strongly in the chest area. I believe the presence of higher harmonic frequencies with good balance all the way up essential for this sensation. The ULF itself makes the least contribution to the sensation but helps fill it out and make it more real and present. It's just too bad that the good bass was totally missing from a lot of transient effects. Anyway, I have a hard time believing that the problems with this soundtrack were intentional. It's certainly possible that people misjudged the quality of the track because they were too tired or something. Or maybe people were just rushed. Maybe mistakes were made that were to difficult to correct. Still, this is bad enough that I think it'd be reasonable to ask for a correction and recall. I didn't buy this film, and have no interest in doing so after what I experienced. Still, I hope this isn't an example of Disney's future. I thought some of the Pixar films like "Coco", "Inside Out", and "Finding Dory" were fine as far as dynamics were concerned. They might have been pulled back a bit compared to typical cinema tracks, but I kind of expect that with kids movies. And anyway they still were *way more dynamic* than "Black Panther". Edit: Just to clarify with my opinions regard to discussion in some of the recent posts: I thought "Black Panther" and "The Last Jedi" were kind of at opposite ends of sound quality and performance. TLJ had very nice dynamics, it just needs high master volume to get things nice and loud. BP is about the same average loudness as TLJ was (7.1 at least) but had practically no dynamics at all, for which there's no real cure. BP really looks like a QC error as does the Thor:Ragnorok Atmos track which apparent has severe compression but only for the first half. I hope it's just these two, but I guess I'll find out how Avengers 3 is.
  13. SME

    Ricci's Skhorn Subwoofer & Files

    Do you have any real world examples of this kind of positive feedback loop occurring, causing unexpected bottoming or failure due to uneven power dissipation? Or maybe just really bad sound? I'm skeptical, but I'm also paranoid. I'm also a bit paranoid about having multiple drivers share the same air space. I opted for a solid barrier between air spaces within my dual-opposed sealed subs. You might want to consider that too if these kinds of interactions between drivers are really a problem for you.
  14. SME

    Ricci's Skhorn Subwoofer & Files

    Are these DVC drivers? I believe manufacturing variance, possibly amplified by the loading of the cabinets, could play a role in unexpected differences in series vs. parallel performance. I don't believe such difference will only one voice coil. It is when there are multiples that you get a series connection between two VCs instead of between a VC and the amp, and that is where I can imagine some unusual electromechanical behavior to arise if manufacturing variances are significant. Just an idea.
  15. SME

    The Bass EQ for Movies Thread

    Apologies for taking so long to give a review. I *finally* watched this tonight! I just kept putting it off because I've been working so hard on new/improved treble optimization. I'm still not done and was thinking I'd save it for when I'm "done", but my wife got tired me of putting it off. I'm glad I listened to her. I think this is my new favorite soundtrack, and the BEQ takes it to 110%. I watched it (BD/Atmos soundtrack) at around "-5" on the MV. (I forgot to check to see if there was any dialnorm modification to that, so it might have been less). My system is configured with a pretty generous house curve (up to 10-12 dB "hot"). Pretty much all of the bass sounded full bandwidth, and the frequency balance was excellent. At no point did the low stuff overwhelm the mid-bass nor any of the rest of the spectrum. The sound effects were very cohesive from top to bottom, and the tactile sensations were detailed, articulate and at times brutal. There were multiple jaw-drop "jump out of my seat" moments where things just went BOOM spectacularly. The surround work in this mix was a big part of experience as well. What can I say? This this a superb demo piece: for my bass capability, my overall sound capability, for BEQ as a technique, for superb sound design, etc. It is state-of-the-art. A big thanks to @maxmercy for taking the time to do this!
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