Shredhead Posted May 25, 2015 Share Posted May 25, 2015 I picked a volume level on a bluray disc player with analog outs and recorded the waveform of the Voltage on the subwoofer output while playing various movie scenes. This voltage includes the re-directed bass from all 7 channels. The vertical scale on waveform grid is 1 Volt per division for all of the following movie scenes. How many Volts this particular player outputs for the content isn't important, it just shows the difference in output for different movie mixes. The readout next to the waveform below tells what the peak positive voltage level is and then the peak negative voltage. When you add the 2 together, you get the peak to peak value (Vpp). I tried to pick the hottest scenes of the following movies. There are some lower level movies included here to give a frame of reference but mostly there are sub crushing monster soundtracks. Seeing the difference in the voltage levels of the low level films vs. the heavy weights, it's no wonder why when you pop in certain soundtracks like HTTYD you have to be very careful where your sub trim and MVL is set to so that you don't overdrive your amps and drivers. Let's start with a lower level film mix... Avatar. DTS-HD MA 5.1 -This is the scene where the tree falls -12.04dBV from WCS Edge of Tomorrow. DTS-HD MA 7.1 -The square wave intro -7.04dBV from a WCS Earth to Echo. DTS-HD MA 5.1 -The ship at the end of the film -2.03dBV from a WCS Godzilla. DTS-HD MA 7.1 -1 hour, 40 minutes in where Gozirra fights Mothra (or whatever that thing is supposed to be) -5.78dBV from a WCS Guardians of the Galaxy. DTS-HD MA 7.1 -Intro of movie where Chris Pratt says he is Starlord -6.52dBV from a WCS Link to comment Share on other sites More sharing options...
Shredhead Posted May 25, 2015 Author Share Posted May 25, 2015 War of the Worlds. DTS-HD MA 5.1 -Bridge collapse I found it interesting how much weaker the DVD's dolby digital mix was than the DTS mix. And I was really surprised to see that the DVD's DTS mix is actually hotter than the Bluray's master audio DTS track. -11.13dBV from a WCS (DVD DD 5.1) -4.08dBV from a WCS (DVD DTS 5.1) -6.27dBV from a WCS (Bluray DTS-HD MA 5.1) -5.1 DTS DVD Here is a demo disc that maxmercy made for me that has almost 0dBFS of a 40Hz sine wave on all 7 channels re-directed and summed with the LFE. This is an absolute worst case scenario and it isn't possible to have a hotter level out of the sub out than this. It should be clarified that max encoded the levels down from 0dBFS by -0.1dB on all channels. Usually digital audio discs are mastered down from 0dBFS anywhere from -0.1dB to -0.5dB because in cheaper DAC's a full 0dBFS signal will come out clipped. -0dBV from a WCS. I will add more waveforms for hot content as time permits. Link to comment Share on other sites More sharing options...
Shredhead Posted May 26, 2015 Author Share Posted May 26, 2015 How to Train Your Dragon. Dolby True HD 5.1 -Dragon Crash -1.44dBV from a WCS Interstellar. DTS-HD MA 5.1 -Right before the ship's automated warning is telling him to eject -3.17dBV from a WCS Oblivion. DTS-HD MA 7.1 -"Coming in hot" -7.9dBV from a WCS Pacific Rim. DTS-HD MA 7.1 -The opening battle -4.68dBV from a WCS Thor. DTS-HD MA 7.1 -"Then GO!" in the frost giants battle scene -4.48dBV from a WCS Just a quick note: The HTTYD dragon crash is only 1.44dBV from a WCS (worst case scenario). Earth to Echo is 2.03dBV from a WCS. Interstellar is 3.17dBV from a WCS. While Avatar is down 12.04dBV from a WCS. I wouldn't be surprised as the loudness wars progress if a movie comes out that maxes out the headroom completely for a brief period. It would be a powerful/potentially dangerous effect. Another thing interesting to me is that while some newer movies like EoT and Interstellar are using either clipped channels or aggressive limiting to create square waves it must be for the effect that square waves add to the mix because they don't seem to be maxing out the total headroom in all re-directed channels. I also don't understand why anyone would choose to hold the bass levels down such an extreme degree as 15-20dB from a full reference output. From what I understand, the farther from 0dBFS you get, the more distortion increases in digital audio. Link to comment Share on other sites More sharing options...
tuxedocivic Posted May 26, 2015 Share Posted May 26, 2015 Great info. Thanks. Link to comment Share on other sites More sharing options...
Bossobass Dave Posted May 26, 2015 Share Posted May 26, 2015 Yeah, paste the -x.xxdBV from WCS on the waveform graph as well if you can. This info is golden and should be attached to the MWB list by adding the graph to the linked post with the peak hold/average graph. If you can come up with an easy way to factor in content, then this would be a perfect objective way to say which scenes are most intense from a playback stand point with little room left for debate. Link to comment Share on other sites More sharing options...
coolrda Posted May 27, 2015 Share Posted May 27, 2015 Nicely done. I'm a sucka for graphs and graphics. Good examples of loud vs dynamic. Never understood all the fuss over that Interstellar scene. And I don't get why the DVD is superior to the bluray soundtrack in with so many movies. Master and Commander is another example. Ice Fields from Titan A.E. is a challenge. Link to comment Share on other sites More sharing options...
maxmercy Posted May 27, 2015 Share Posted May 27, 2015 I have a request. Transformers 1. Megatron Blasts Jazz. You can see the ULF pulse. It won't be as hot as some of the others, though. Great Thread. JSS Link to comment Share on other sites More sharing options...
MemX Posted May 27, 2015 Share Posted May 27, 2015 Great work! Some of those heavy hitters are pretty monstrous Link to comment Share on other sites More sharing options...
mojave Posted May 27, 2015 Share Posted May 27, 2015 Just a quick note: The HTTYD dragon crash is only 1.44dBV from a WCS (worst case scenario). I also don't understand why anyone would choose to hold the bass levels down such an extreme degree as 15-20dB from a full reference output. From what I understand, the farther from 0dBFS you get, the more distortion increases in digital audio. Don't your voltages from a WCS only relate to your particular Blu-ray player? For example, I can output 30V+ p-p (+24dBu is 34.7 p-p) and I'm sure the voltage difference from HTTYD and WCS would be different. Maybe it would be better to show as a percentage. People's crossover frequency, LFE low pass, and filter slopes will also factor in how they relate their output levels to your's. I analyze all tracks of all movies I watch. Almost all tracks get very close to 0dBFS. 3ll3d00d should be able to confirm with his movies. However, you lose a lot of headroom when you use bass management. This is even more prevalent as when you go to a 7.1 track. As you saw with the OPPO, it is up to the manufacture how they will manage the bass and what tradeoffs they feel are important. Some desire to preserve sound quality and output levels over the majority of content (OPPO) while others will allow more headroom at the expense of loss of low level signal detail due to using fewer bits for output. Below is the first 00:03:15 of EOT showing that the waveforms reach close to 0dBFS for the center and LFE channels. The entire movie is mastered at 0 dBFS and at +1.4 dBFS when you take intersample peaks into consideration. Here are three methods of bass management on EOT. The first is using peak level normalization which will make sure the volume is still as loud as possible. The third is how a typical Blu-ray player or receiver will have to do bass management for a WCS. Link to comment Share on other sites More sharing options...
Shredhead Posted May 28, 2015 Author Share Posted May 28, 2015 Don't your voltages from a WCS only relate to your particular Blu-ray player? Yeah, like I said it's not important cause it's all relative to dBV and if my player isn't doing management like other pieces of equipment I plan on showing that too with this experiment. My computer's PSU shit itself so when I get it sorted I'll post some more stuff. Link to comment Share on other sites More sharing options...
maxmercy Posted May 28, 2015 Share Posted May 28, 2015 Here are three methods of bass management on EOT. The first is using peak level normalization which will make sure the volume is still as loud as possible. The third is how a typical Blu-ray player or receiver will have to do bass management for a WCS. Edge of Tomorrow Bass Management.PNG Please elaborate on the different bass management schemes shown (and implemented in gear). Those waveforms are quite different in amplitude. JSS Link to comment Share on other sites More sharing options...
3ll3d00d Posted May 28, 2015 Share Posted May 28, 2015 I analyze all tracks of all movies I watch. Almost all tracks get very close to 0dBFS. 3ll3d00d should be able to confirm with his movies. I posted a list I pulled out of my library in http://data-bass.ipbhost.com/index.php?/topic/379-maxmercys-wcs-test-disc-beta-and-an-o-scope/?p=6359 It shows that films invariably max out the main channels but that it's less common to do so on the LFE channel. Obviously this is only the peak value for the track and it says nothing about whether those peaks are aligned or what the overall level throughout the film is like. Link to comment Share on other sites More sharing options...
mojave Posted May 28, 2015 Share Posted May 28, 2015 Please elaborate on the different bass management schemes shown (and implemented in gear). Those waveforms are quite different in amplitude. JSS I shouldn't have called it bass management. They are just all channels combined but with different level of attenuation used. The first used peak level normalization to maximize volume without clipping. The third uses the -10.2 dB on LFE and -20.2 dB on other channels you recommended to me for use for spectrum lab analysis. The middle one is about half way in between with -4.8 dB on the LFE channel. It is similar to what is used by a receiver that did not take into consideration the extra two channel in 7.1 content and still used downmixing levels used for 5.1 channels. I was told by Roger Dressler that this happened for a while after 7.1 was introduced. Link to comment Share on other sites More sharing options...
3ll3d00d Posted May 28, 2015 Share Posted May 28, 2015 I shouldn't have called it bass management. They are just all channels combined but with different level of attenuation used. The first used peak level normalization to maximize volume without clipping. The third uses the -10.2 dB on LFE and -20.2 dB on other channels you recommended to me for use for spectrum lab analysis. The middle one is about half way in between with -4.8 dB on the LFE channel. It is similar to what is used by a receiver that did not take into consideration the extra two channel in 7.1 content and still used downmixing levels used for 5.1 channels. I was told by Roger Dressler that this happened for a while after 7.1 was introduced. that is actually consistent with shredhead's captures from his oscope then isn't it? i.e. your 3rd graph hits about 0.45 which in the region of ~7dB down from the peak and this is about the same headroom as indicated by his readings (of 2.56V vs 5.72V) is the first one just the output from jriver with Adaptive Volume/Peak Level Normalize turned on? i.e. the user is left to set MV to their preference (on a track by track basis) Link to comment Share on other sites More sharing options...
Shredhead Posted May 30, 2015 Author Share Posted May 30, 2015 A quick note to all out there who use HTPC's.... My computer recently power cycled in the middle of watching a video. I thought the power went out but just as soon as I realized it had not I started to smell the magic smoke escaping so I reached over to my computer which was in the middle of booting up and turned the power off to it as soon as possible. I have a 120mm fan that is switchable on separate power from my computer's PSU so I turned it on and it was pumping out hot, stinky air. No good. It was my PSU dying probably due to dried up electrolytic caps and going into wild oscillations. Here are some measurements I took of the old faulty one vs. a new one with and without a load on the 12V rail. It is normal to have some switching noise on a computer's PSU but you can see that this was far too much noise for any digital electronics. The switching noise is at ~91kHz so if you were to zoom out, you would see a brick wall of PSU noise. PSU noise seriously messes with digital electronics in unpredictable ways as I already mentioned in other threads about the iNuke series of amps with their power cycling problems. I'm pretty sure this PSU would have destroyed itself (and probably my MB as well) from oscillating had I not caught it in time so just a heads up to the other PC users out there: watch out for power cycling and abnormal heat from PC PSU's. Link to comment Share on other sites More sharing options...
Shredhead Posted May 30, 2015 Author Share Posted May 30, 2015 Oz -the Great and Powerful. DTS-HD MA 7.1 -Balloon gets sucked into tornado Link to comment Share on other sites More sharing options...
Shredhead Posted May 30, 2015 Author Share Posted May 30, 2015 Here is another frustrating case of the DTS Master Audio 7.1 track being the most undynamic of all the mixes. Apparently France gets the best mix on this one. Prometheus. DTS-HD MA 7.1 (bluray), Dolby Digital 5.1 French language track (bluray), and the Dolby Digital English track (DVD) -Ship crash suicide -DTS 7.1 -French 5.1 Link to comment Share on other sites More sharing options...
Shredhead Posted May 30, 2015 Author Share Posted May 30, 2015 Yeah, paste the -x.xxdBV from WCS on the waveform graph as well if you can. I will from now on. I went back to the 1st ones I posted and put the WCS numbers in red. Link to comment Share on other sites More sharing options...
LTD02 Posted May 31, 2015 Share Posted May 31, 2015 pretty cool. Link to comment Share on other sites More sharing options...
nube Posted May 31, 2015 Share Posted May 31, 2015 I've noticed that neither you nor your dad ever demo the Washington Monument scene from Olympus Has Fallen (tops on the list at that link). I wouldn't say it's a good movie, or even a very fun one, but that scene is definitely a contender for most difficult sustained scene to reproduce. I added the E2E scene right below the OHF scene at that link, just for reference. The length of it is killer, plus that big 1-3Hz hit that's coupled with all the intensity 10-30Hz. I'd love to see how it does both short and long term in this measurement, as well as in your guys' playback SL captures, if you could start to incorporate it into your rotation. Link to comment Share on other sites More sharing options...
Madaeel Posted May 31, 2015 Share Posted May 31, 2015 Nube here's a SL cap of that scene which I use as a reference and also which made me realize the near field Raptor was shit. My 5-10hz was better but from 10-25hz I had a huge null. Back up front where they belong. Of course I'm not reading anything from 1-3hz but everything else is there. Link to comment Share on other sites More sharing options...
Shredhead Posted June 3, 2015 Author Share Posted June 3, 2015 I'll get on the Transformers 1 for ya max. Is it at the end where they are fighting in the city? nube, I've been hearing about that scene for a while now but we don't have the movie and I've never seen or experienced it. I'm pretty sure Bosso watched it at some point and he might have capped some SL action but I can't remember. I'll keep an eye out for the movie in bargain bins. Link to comment Share on other sites More sharing options...
maxmercy Posted June 3, 2015 Share Posted June 3, 2015 Yup, right after Megatron shows up in the city. He blasts Jazz with his arm cannon and it is the strongest ULF transient in the film. For comparison, you could do the tank (wrongly named devastator) dying or Ironhide's flip, both of which had significant content in different registers. Thanks! JSS Link to comment Share on other sites More sharing options...
MKtheater Posted June 3, 2015 Share Posted June 3, 2015 I tried running spec lab on that scene but my computer stopped seeing the 975 for some reason so I went to bed. Just start playing at " It's Megatron" and you will know! The woofers dance for that scene. Link to comment Share on other sites More sharing options...
Shredhead Posted June 12, 2015 Author Share Posted June 12, 2015 "9" DTS-HD MA 5.1 Cannon shoots at spider Link to comment Share on other sites More sharing options...
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