Never seen any Hellboy, never seen Epic.
How about Open Range? It is 10 years ago or so, but a good film and exhilarating gunfire. I seem to remember energy all the way down,...but I'm uncertain about the characteristics; ie., how often and how deep. It's demo worthy stuff regardless how deep. One of the finest gunfights ever produced.
Open Range is in the queue.
You're right, I agree. The Hurt Locker is a great film, and the sound, in all aspects, is just fantastic.
How significant is the clipping you illustrated in the submitted image? What I mean is how often do you encounter that heavily lopped off clipping, and can you or anyone quantify the subjective end result? How would that sound? You've been pouring through all these soundtracks, there would be few (if anyone) outside the industry more adept to assign some relative importance to such an occurrence. I realize unless we had an interview with the sound team that participated, we're not going to know for sure. But wth, we can speculate.
The short answer: It depends....so many variables. In both DTS-HD and Dolby TrueHD, the LFE channel is full bandwidth. It can contain 20kHz if it wants to. The signal chain almost always applies a lowpass, though. AVRs have an adjustable one for LFE (I set mine as high as I can to catch everything I can that is encoded, Like Loki trying to pick up Thor's hammer in the crater unsuccessfully, HUGE 140Hz content), and almost all sub amps have one built in as well.
As you said it could be intentional, for effect, etc. But there are soundtracks that possess what many would consider inexcusable mistakes. I've performed my share of live recording, even sound effects. For fidelity reasons, you always want to hit the media as hot as possible without overload. It could've been anything from a clip that they really needed to include despite it's clipping. Or just as simple as aggressive limiting by design.
This could be hard limiting, because it is below 0dBFS, like all the other channels.
Although I've not read or participated in any such discussions, I'm guessing this issue has been fully explored before. I'm curious what the LFE signal sounds like as one bumps it up until severely flat topped like that. Anyone here performed such experiments? With the inherent filtering accompanying the LFE channel, I'm wondering what subjective audible effect such flat topping has on the final result. Another way to ram more average level down the pipe? The LF drives aren't going to track the horizontal component of the signal, so is this intentional simply for more level? Any idea of the approx. freq range of the waveform? Looks like ~50hz or so, in the center of the graph.
Curious that you ask.....I ran some experiments on this very thing. It is a 100Hz waveform just to the right of center, with 0.01sec period. If I generate a 100Hz waveform at -0.5dBFS, and amplify it by 6dB (clipping it all to Hell), then turn it down by 2dB, I get almost the same waveform displayed (clipped at -2dBFS). When played back, it sounds like a bad fuzz pedal, and definitely not like a clean tone, all odd-order harmonics. But if I apply a 250Hz lowpass at 12dB/octave to the clipped signal, it then appears to be soft-limited, with smoother edges, and has a much nicer distortion profile, and sounds like a moderate tube overdrive, instead of a hard fuzz. Still odd-orders, but only the 300Hz component is readily audible. It sounds much cleaner. If the mixing stages have lowpass circuitry built into their signal chains, nothing will warn them that they are clipping the LFE channel, as it will only sound mildly overdriven. They may find that if they remove lowpasses from it, that they run into bad sounds with hard limiting or 0dBFS. I think that they may be oblivious due to the lowpasses that may be in place, both on the board, and in the crossover/amp chain. I usually see clipping in the center channel first, then LR, and then surrounds, then LFE. I see the least amount of clipping on the LFE channel, but when it is there (Immortals, The Hurt Locker), it is pretty bad, but may be insignificant due to processing in amps, an AVR or mixing board.
I've experienced The Hurt Locker over many occasions/many systems. Actually, it's my experience that it's used quite often in CEDIA/tradeshow demonstrations. In addition to my own system, I've seen it over some bad-ass, highly capable systems. I've not been actively looking for issues, but I've never heard anything but first rate audio excellence out of that release.
Maybe because all of those systems low-passed. The difference is night and day. See attached. 100Hz Sine, 100Hz clipped waveform, 250Hz lowpass, 120Hz lowpass.....The 120Hz lowpass has less than 4% harmonic distortion, with the 300Hz component over 32dB down from the 100Hz fundamental. With LCRS blaring at the same time, no trained ear would pick that up, it would all be masked.
Maybe I need to pay closer attention, is there any release known for audible LFE channel clipping issues?
Immortals clipped every channel, but it was nearly pure ULF square waves on some portions of the LFE. With a ULF Square wave, that's a LOT of LF and midbass harmonics, which are audible and dissonant. Again, it may have been intentional, they may have wanted the odd harmonics in order for a 'louder sounding' sound.....Poseidon slamming into the sea and the resultant oil tsunami is a pretty bad scene for distorted sound....
But Tron:Legacy, famous for clipping every other channel, had a pristine, clip-free LFE channel......