maxmercy Posted February 18, 2015 Author Report Share Posted February 18, 2015 I also remeasured the Outlaw 975. No matter what volume level or speaker trims, it is a distorted SW out signal with WCS. it must not have enough headroom for the digital summation internally. The one thing the Outlaw does very well is it has a better ULF rolloff than the Denon, with -3dB around 2Hz, vs the Denon around 5Hz. JSS Link to comment Share on other sites More sharing options...
Madaeel Posted February 18, 2015 Report Share Posted February 18, 2015 Oh I thought you said the Denon had a -3db point under 2hz? Link to comment Share on other sites More sharing options...
3ll3d00d Posted February 18, 2015 Report Share Posted February 18, 2015 I have read previously that the normal way to do bass management was to - attenuate all channels inc LFE by 5dB - sum all the channels except for LFE - reduce that sum by 10dB - sum with the LFE channel - add 15dB gain If this is correct then manufacturers are allowing for 5dB for bass management but you're asking for ~10dB, these values don't agree so it seems clipping should be expected. Link to comment Share on other sites More sharing options...
Shredhead Posted February 18, 2015 Report Share Posted February 18, 2015 I also remeasured the Outlaw 975. No matter what volume level or speaker trims, it is a distorted SW out signal with WCS. Wow. Link to comment Share on other sites More sharing options...
maxmercy Posted February 19, 2015 Author Report Share Posted February 19, 2015 Oh I thought you said the Denon had a -3db point under 2hz? Yes, when I used my soundcard loopback cal. But since I was sending a digital out without rolloff, the loopback cal exaggerated the low end response....taking a DAC out of the chain makes it look much better than it really is sometimes. The Outlaw, when bass managed with nanoAVR, has been the lowest digging signal chain I have run thus far, but it is noisier than the Denon. If only MiniDSP could make a nanoAVR with XLR outs, the ability to do multiple subs, and big enough output caps to have insignificant rolloff....you'd have a terrific tool at your disposal. JSS Link to comment Share on other sites More sharing options...
Madaeel Posted February 19, 2015 Report Share Posted February 19, 2015 So that was HDMI? The Outlaw has a great roll-off but can't send a clean signal out the LFE. Funny how that works.. Link to comment Share on other sites More sharing options...
MKtheater Posted February 19, 2015 Report Share Posted February 19, 2015 I know what you are doing but are any movies out there that send WCS to the SW outputs like you are testing? If not than maybe this is why people have not commented on bad sounding bass when running hot? You said HTTYD comes the closest but not quite and for maybe 5 seconds while the rest of the movie won't clip? Link to comment Share on other sites More sharing options...
maxmercy Posted February 19, 2015 Author Report Share Posted February 19, 2015 If you run subs hot, the more potential that is there for this type of clipping to occur. Movies like TDKR, Godzilla and TF4 come closer to WCS than HTTYD. HTTYD was near WCS but was an unclipped wVeform to begin with, unlike the other films mentioned. JSS Link to comment Share on other sites More sharing options...
Shredhead Posted February 19, 2015 Report Share Posted February 19, 2015 You said HTTYD comes the closest but not quite and for maybe 5 seconds while the rest of the movie won't clip? I care the most about what the system does in those 5 seconds, don't you? Most of these tests so far reflect that most preamp/decoders are failing by ~10dB. That is significant and would affect more than just HTTYD. Link to comment Share on other sites More sharing options...
MKtheater Posted February 19, 2015 Report Share Posted February 19, 2015 I care, I prepare my system just so I can do it, thank your Dad for that! I was just saying how many can say their system sounds good. Max, Can one still reference and over using the NanoAvr in the chain with something like the 975? -3 dB at 2hz is awesome. Link to comment Share on other sites More sharing options...
MKtheater Posted February 19, 2015 Report Share Posted February 19, 2015 BTW, I am trying out that Octava HDMXA71 with my NanoAvr. Link to comment Share on other sites More sharing options...
3ll3d00d Posted February 19, 2015 Report Share Posted February 19, 2015 this thread got me thinking about my HTPC setup and led me to run the tests described in http://yabb.jriver.com/interact/index.php?topic=95717.msg659405#msg659405 I figured I would do this digitally only first as it's quick and easy to do. I think the results suggest that jriver is implementing that same "leave 5dB headroom for summation" approach as I referenced earlier. I did some googling earlier and that suggests this was the dolby specified approach back in the day. If so then I would argue this is a test designed to prove that nearly all consumer gear will fail and that one of the only passing approaches will be a purely custom HTPC solution. If that is correct then how relevant is this test really? you could argue that HTTYD is actually an indication of a failed mix process in that light (i.e. one that will clip on nearly all consumer kit) NB: the link referenced above to some dolby spec was a dead link from ~2009 so the possibility remains that it may have been superceded, no immediate evidence to that direction though Link to comment Share on other sites More sharing options...
Bossobass Dave Posted February 19, 2015 Report Share Posted February 19, 2015 Yes, that's a good distinction to note. HTTYD is much more difficult to reproduce accurately than most any other snapshot simply because it ADDs a couple of octaves to an already wide bandwidth spread vs most others. That doesn't mean that other effects with less bandwidth don't qualify for a WCS. Paul & I have been looking at the Earth To Echo scene that lasts for more than a minute and a half (90 seconds) as a candidate. I reported it's brutality back last November when I got the disc. Previous to spinning the disc, I had the SW trim bumped to approximately +8dB and all sorts of radical things happened when this scene came up. I did the dive for the remote and stopped it mid stream. I then went back and capped the scene in SL after reducing the SW trim by -6dB (so, at +2dB hot) from where it was the first run through and posted it in the ETE thread. We measured the scene with a voltage peak of 1.951V, which is very close the the HTTYD scene, except that this scene is nearly 2 minutes long with no let up and, as you can see in the graph below, was produced or mixed with a brick wall limiter in line. That, of course, brought the peak to average about 65 times closer than the peak to average for the whole movie. I never would have seen the limiting because I almost never do SL caps off the player and when I measured this scene by mic'ing the subs, the limiting did not show up in the mic'd version waveform. Here's a closeup of the difference between waveforms in dgital feed vs mic'd: Now, this really threw me for a loop. But, as Paul pointed out when I asked him why the 2 versions of waveform were different, you can't reproduce a high-end limiter's effect acoustically. But, it certainly explains the difficulty in running this scene hot without aggressive limiters in line. Bottom line being that, even though HTTYD measures a voltage peak that's a tad higher, since most systems aren't ever gonna reproduce the dragon scene accurately to 8 Hz let alone to 2 Hz and, therefore, no worries on the difficulty scale, the scene from ETE is much more of a danger and will actually measure a higher peak voltage than HTTYD within the bandwidth of most systems. Add to that that many folks are not playing this back at reference or below, and when you run a limiter-squashed scene hot, one that's already encoded at a measured 5 star level and is 2 minutes long, the WCS is redefined. Link to comment Share on other sites More sharing options...
Bossobass Dave Posted February 19, 2015 Report Share Posted February 19, 2015 this thread got me thinking about my HTPC setup and led me to run the tests described in http://yabb.jriver.com/interact/index.php?topic=95717.msg659405#msg659405 I figured I would do this digitally only first as it's quick and easy to do. I think the results suggest that jriver is implementing that same "leave 5dB headroom for summation" approach as I referenced earlier. I did some googling earlier and that suggests this was the dolby specified approach back in the day. If so then I would argue this is a test designed to prove that nearly all consumer gear will fail and that one of the only passing approaches will be a purely custom HTPC solution. If that is correct then how relevant is this test really? you could argue that HTTYD is actually an indication of a failed mix process in that light (i.e. one that will clip on nearly all consumer kit) NB: the link referenced above to some dolby spec was a dead link from ~2009 so the possibility remains that it may have been superceded, no immediate evidence to that direction though It was never a Dolby spec. Dolby created the bass management configurations but Cirrus Logic got the patent for digital bass management. Here is a link: http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&p=1&u=%2Fnetahtml%2FPTO%2Fsearch-bool.html&r=7&f=G&l=50&co1=AND&d=PTXT&s1=%22bass+management%22&s2=%22cirrus+logic%22&OS=%22bass+management%22+AND+%22cirrus+logic%22&RS=%22bass+management%22+AND+%22cirrus+logic%22 Go to images and scroll to Table 4 Dolby configuration '0' for the scheme and to the left is the explanation. Link to comment Share on other sites More sharing options...
3ll3d00d Posted February 20, 2015 Report Share Posted February 20, 2015 Thanks for the link. It seems I must be missing something though, what is it? If the patent, which presumably most people implement, says "allow 5dB" but this test is asking for >5dB then why do we expect anything to pass this test? Link to comment Share on other sites More sharing options...
Shredhead Posted February 20, 2015 Report Share Posted February 20, 2015 you could argue that HTTYD is actually an indication of a failed mix process in that light (i.e. one that will clip on nearly all consumer kit) HTTYD is not the only movie that pushes that kind of level on the sub output at reference with the trim at 0dB. As Max has already pointed out, there are more and more movies with clipped digital levels on some channels on the disc. It seems as the loudness war progresses it would be wise to examine the WCS before our equipment becomes a casualty of war. Link to comment Share on other sites More sharing options...
maxmercy Posted February 20, 2015 Author Report Share Posted February 20, 2015 Bosso, You are spot on. Clipped and brick wall limited tracks are essentially square waves, a torture test that can be potentially worse than the WCS track, as low passing and DAC can then exceed the analog equivalent of 0dBFS (see 0dBFS+). No subwoofer can hope to faithfully replicate those clipped corners, and overshoot can harm equipment in more ways than one. I do not intend to create a square-wave WCS track, but I may have to in the future, given some of the tracks we have seen lately... JSS Link to comment Share on other sites More sharing options...
maxmercy Posted February 20, 2015 Author Report Share Posted February 20, 2015 Thanks for the link. It seems I must be missing something though, what is it? If the patent, which presumably most people implement, says "allow 5dB" but this test is asking for >5dB then why do we expect anything to pass this test? Because someone hopefully realized that the 7.1 spec requires >10dB headroom for proper summation. It will get worse with the newer, more channels bass-managed formats. And have no fear, with more Transformers films on the way, I will bet that added bass SPL capability will be used. How many EoT BluRays do you think were sold simply for the first 30 sec? JSS Link to comment Share on other sites More sharing options...
maxmercy Posted February 20, 2015 Author Report Share Posted February 20, 2015 BTW, I am trying out that Octava HDMXA71 with my NanoAvr. Very interested to hear what you think of it. I thought about buying it. JSS Link to comment Share on other sites More sharing options...
MKtheater Posted February 20, 2015 Report Share Posted February 20, 2015 I will let you know. If I don't get my system built soon I can ship it to you to test out. I have 30 days to return if it does not work out. It does not do any bass management so one can't use it as a processor by the nano does that for me. I just wanted a volume control and convert to analog to my amps. Link to comment Share on other sites More sharing options...
3ll3d00d Posted February 20, 2015 Report Share Posted February 20, 2015 Because someone hopefully realized that the 7.1 spec requires >10dB headroom for proper summation. Well I don't think you should get your hopes up given the almost complete absence of innovation in the prepro market. I am not saying this is a good thing of course, just being pragmatic... Get a htpc and do it yourself FWIW I updated that thread on the jriver board with details of how I tested their bass mgmt (http://yabb.jriver.com/interact/index.php?topic=95717.msg659468#msg659468), it looks to me like it (jriver) has the same problem. I think the interesting models to test would be something like a marantz 7702, the datasat and the trinnov. ie a modern midrange atmos prepro, an older high end piece and a modern PC based design. Link to comment Share on other sites More sharing options...
3ll3d00d Posted February 20, 2015 Report Share Posted February 20, 2015 As Max has already pointed out, there are more and more movies with clipped digital levels on some channels on the disc. It seems as the loudness war progresses it would be wise to examine the WCS before our equipment becomes a casualty of war.Why does clipping in the source make this problem worse? Just because it becomes more likely that multiple channels sum to more than the 5dB allotted? Link to comment Share on other sites More sharing options...
Shredhead Posted February 20, 2015 Report Share Posted February 20, 2015 Max's WCS is using sine waves that are held down from reference .1dB. If sound engineers start using super limiters to create square waves, ramp them up to that level and then sum a few channels of that it will be much more demanding on your amplifier and drivers. At least if we calibrate to Max's sines, or HTTYD our peak level analog out will not be clipped. If your signal chain isn't calibrated for worst case and they mix a worst case with aggressively limited square waves, your clipped analog out will square them even further and you will be outputting a signal that is so chopped that it almost resembles DC. Anyone who has experience with limiter plugins for mastering audio with attest to how much louder they can make dynamic material depending on the threshold. They can greatly raise the average level of output for an amplifier. http://data-bass.ipbhost.com/index.php?/topic/284-bossobass-raptor-system-3/page-32 The OPPO passed the HTTYD test. I also show an AVR's out that failed and explain my thoughts on how this can be dangerous. Link to comment Share on other sites More sharing options...
3ll3d00d Posted February 20, 2015 Report Share Posted February 20, 2015 what is the significance of using a -0.1dBFS sine wave vs 0dBFS? Link to comment Share on other sites More sharing options...
Shredhead Posted February 20, 2015 Report Share Posted February 20, 2015 It is smart to master audio a bit down from 0dBFS because cheap DAC's will clip at 0dB. It still doesn't stop some engineers though. Link to comment Share on other sites More sharing options...
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