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Showing content with the highest reputation on 09/17/2018 in all areas

  1. 1 point
    I don't have confirmation of this, but I believe that many Disney and Skywalker Sound mixes in general have more mid-range and less bass than typical cinema content. I believe this is actually a good thing, even though it may reduce apparent loudness and/or dynamics compared to most other mixes. These mixes are likely to sound better on the vast majority of audio system out there including systems optimized for music playback. However, the response of different home systems varies a lot, and the variance is not necessarily any better for "full blown home theaters" vs. TVs and hand-held devices. For example, a lot of auto-EQ calibrate to targets that are bass deficient, IMO. If the Disney/Skywalker Sound movies sound whimpy, even after adjusting the master volume up, it may be in part because the playback system is calibrated to a bass deficient target. Cinemas are also bass deficient because the lower part of the X-curve is flat, whereas a natural in-room response from an anechoic flat speaker typically rises toward the bass in the bottom. Cinemas are also treble deficient because of the steep -3 dB/octave roll-off in the upper part X-curve vs. between 0 and 1 dB/octave with an anechoic flat speaker. I personally find most of the Disney/Skywalker soundtracks to be quite satisfying on my system, which has a substantial "house curve", consistent with a flat anechoic response. I do wish the tracks were more consistent though. Even though most of the Disney/Skywalker stuff has better balance between bass, mids, and treble than typical cinema tracks, the balance within each region is often weird. A lot of this probably reflects the limits of existing calibration technology, which is an area I'd like to see improvement. While most rooms exhibit fairly similar in-room response characteristics when using anechoic flat speakers, the differences are enough that calibrating to the same in-room target in different rooms won't lead to consistent sound. In the long run, it would be good to see the X-curve standard for cinema and dub stages go away to be replaced by a truly accurate calibration standard. This would likely eliminate one of the biggest differences between cinemas and home systems. Better yet, with all the production done on accurate systems, much less EQ would be applied to the mixes overall leading to a much better result overall on *all* systems *including cinemas*, where sound is often the worst. Indeed experiments suggest that cinemas sound better with anechoic flat speakers than with the X-curve calibration, *even when playing cinema content* mixed in X-curve calibrated dub stages. Yeah, really!
  2. 1 point
    Regarding Disney's recent HT mixes, I can only second what others are saying about them : they are disappointing, and no, it's not just a question of loudness or master volume. What's interesting is to compare how it pored through video releases : the Forbes article has the starting point wrong : AOU was already problematic on BD. It was under-cranked, but also flatter than expected and with empty bass (I suppose the track doesn't go particularly low in frequencies). Its unfortunate the article is imprecise regarding this (though I guess that can only be expected from a non-technical publication like Forbes), but having now listened to many of the recent Buena Vista BDs, they do feel disappointing outside from the master volume being too low. They certainly aren't all the same, and some sounded better than others, but AOU, Black Panther, Last Jedi, Thor Ragnarok, GoG 2, but also things like Coco. Infinity War sounds a bit better and mostly is slighlty under-cranked, but even once the MV is increased, it still feels less impactful that one would expect. I can't say if it's a creative issue more than a technical limitation. But what I do know is that something definitely changed in the way these tracks are mixed, and despite whatever people might say (especially regarding how other studios have clipped or filtered tracks, as if it explains why the BV tracks are picked up but not the other ones, or as if it would somehow makes it better to know that), it's telling to see in the first post of this very thread the scores obtained by earlier MCU discs (Winter Soldier, Incredible Hulk, Thor 2) and then look at the scores for more recent movies. I don't know what Disney changed, but clearly, if they didn't change anything, we wouldn't have this discussion. If they changed it in a way that didn't feel this obviously debatable, we wouldn't have it either. So if Disney wants to simply go back to whatever they were doing 6 years ago, I'm all for it, and I DO hope they listen to the complaints to just go back and do that.
  3. 1 point
    Kodi uses alsa on my machine, and this dsp can use alsa. But it will not work for movies, because audio is sent to hdmi directly as passthrough, for external decode in the av processor. It would be possible to configure to allow software processing if the movie audio is re-encoded to pcm, but then you still would need to extract, decode, encode and re-mux. Options here are severely limited due to the proprietary formats of audio in movies. Which leaves processing post-bm in the bass-system dsp is the best option for quick and reasonable quality bass-eq. This also eliminates problems with clipping.
  4. 1 point
    Another issue that may be a lot more challenging to address is proper support for the lower-end MiniDSP devices, the 2x4 and 2x4 balanced, which use 56-bit fixed point processing instead of floating point. This causes errors due to precision loss below 20-30 Hz, which become worse with decreasing frequency. These errors can be substantial even when using the MiniDSP in the mode that is optimized for low frequencies, without which any kind of ULF EQ is pretty much useless. I got bit by this problem pretty hard back when I used a MiniDSP 2x4 for in-room sub EQ. The errors are not small. Even with a floating point implementation, the precision of the floats may matter. (I haven't thoroughly tested it.) Processing the audio in 32-bit float format should be good enough, but the biquad coefficients and temporary variables may need to be double precision for sufficient ULF accuracy. My implementation does this. I don't know if the floating point MiniDSP units represent the biquad coefficients and temp variables as 64-bit or not. Likewise, I don't know how much precision the fixed point MiniDSP units use to represent the biquad coefficients. These are details that may need to ascertained by reverse engineering in order make tools like beqdesigner as accurate as possible. What about DSP built into amps? It's the same story there too, and each device may behave differently. (This is probably part of the reason many amps don't allow filters below 20 Hz.) These issues don't just affect beqdesigner but affect implementation of the BEQs posted in this thread too. It's just that the independent channel BEQs are designed to be implemented upstream of bass-management, which limits the devices that can be used to apply them to devices that probably have at least 32-bit float precision. Along these lines, it would probably be good to investigate ffmpeg to understand how it will process biquads. I took a look just now. It appears that the internal implementation supports 16-bit and 32-bit integers along with 32-bit and 64-bit float with coefficients always being represented using 64-bit float. The integer formats don't offer any headroom, and because each biquad is processed separately, clipping will occur immediately if any one biquad pushes the signal above full-scale, even if this excursion would have been canceled out by a later biquad. As such, it is crucial that ffmpeg be used in such a way that it uses floating processing internally, and of course, the result will only be accurate for the highest precision floating point DSPs.
  5. 1 point
    @SME, the interest for bass-eq is very, very low considering the huge impact on sound experience. One reason for that is that very few people actually has a sound system capable of reproducing full range with decent capacity and quality. One purpose of this thread was to create awareness, so that the producers deliver better, unfiltered sound in their movies. No bass-eq necessary. Only a few movies deliver that, even today it is rare to see a new release with full frequency range intact. The reason why is that they are clueless - they have no idea that anything is missing in their sound track. No producer would allow a filtered movie to be released if they knew their product could deliver a much better and more involving experience. Most people play the bd and have no option to change the sound track, the only option is to use eq in a dsp somewhere in the chain, and since all decent bass systems has a dsp, it is convenient to implement bass-eq on the bass-system. The drawback is that you can not do individual filtering of the channels. But compared to no bass-eq, this is a good and very useable alternative. I prefer to do individual corrections, because it is better, @maxmercy is very clear on this, he is the true bass-eq purist among us.
  6. 1 point
    This doesn't solve the phase match problem. If one uses a textbook electrical LR4, then the phase shift of the high pass and low pass filter will be identical vs. frequency. However, unless the speaker and sub(s) are ruler flat throughout the crossover region and co-located, they likely won't be phase-matched to begin with. The THX crossover was developed assuming the mains were sealed and had a natural Qtc=0.707 (Butterworth) 2nd roll-off. Two cascaded 2nd-order Butterworths makes an LR4, so the THX crossover applied a single 2nd order Butterworth to the mains and a full LR4 LPF to the subs. Provided that the subs didn't roll-off anywhere within the crossover region, that the mains behaved precisely as specified, and that they were co-located such that room effects applied to each equally, the result was ideal. In reality of course, "bass management" is a stinking mess. The whole point of it was that one could put the subs somewhere better for sub bass, but often the "better" locations are not so good for integrating with mains, especially where multi-listener is a priority. And of course, very few mains are sealed with perfect Qtc 0.707 and Fb 80 Hz. Any significant deviations from there substantially influence the phase response in the critical crossover region. Most mains these days are ported and tuned well below 80 Hz, so they have only slight phase shift at that point. They would do better with a full LR4 HPF, but few AVRs / processors seem to offer more than one XO type. My Denon AVR has the THX 2nd order 0.707 HPF baked in, which totally destroys the bass-managed mid-bass response with any speakers I've owned. The LFE response may measure picture perfect, but the mid-bass response of the other channels looks like trash. Also, how many subs are actually flat through the XO? Most of the beefier drivers are already dropping off from inductance effects. Sad to say, home theater "technology" is still stuck in the 90s in many respects. Great sound pretty much requires extensive customization, as I've learned over the years, and the affordable options for doing so leave a lot to be desired.
  7. 1 point
    To be 100% clear, I absolutely recommend highpassing horns due to their out-of-band distortion performance.
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