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The Low Frequency Content Thread (films, games, music, etc)


maxmercy
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This turns out to be quite simple on the Marantz:

 

- The subwoofer output clips at 4Vrms.

- MV+Trim must be <=-12dB to keep output below clip level at 4Vrms for a highly unlikely 7.1 signal with 0dB level in all channels.

- No combination of signal and trim causes digital clipping before the output clips at 4Vrms.

 

This means that if you watch at 0dB, the subwoofer trim must be set at -12dB to ensure no clipping is possible.

 

Here I have -6dB trim for flat, and that is sufficient for practical soundtrack signals.

However, some movies, such as WOTW, Kon-Tiki, will audibly clip if running 3dB hot with trim level at -3dB.

 

This shows that it definitely makes sense to calibrate subwoofer levels to the lowest possible trim level setting.

Calibrating for 0dB trim will actually loose 12dB headroom before the signal even enters the subwoofer dsp.

 

This is for my Marantz, other processors/avrs may be different.

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Transformers: Age of Extinction (Dolby TrueHD 7.1, no ATMOS content included)

Level - 5 Stars (114.59dB composite)
Extension - 3 Stars (just over 15Hz)
Dynamics - 3 Stars (23.15dB)

Execution - Hotly contested, 5 Stars (by poll)

 

Overall - 4 Stars

 

Recommendation - Buy (by poll)

Notes - It not only appears to be the loudest film of all time, given its nearly 3 hour run time with those numbers, but it definitely sounds and feels that way, see my post on page 2.  It is brick-wall limited at around -0.5dBFS.  In other words, it clips terribly, and often.  As usual, the center channel is the worst offender, followed closely by L, R and LFE.  Surrounds much less so.

JSS

post-20-0-05240600-1412126062_thumb.jpg

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Anyone see Godzilla in a theater with decent capabilities?  Clipping that bad would almost certainly be audible in a movie theater, provided that it isn't running out of headroom for those passages.   I know audio memory isn't very reliable, but I'd really like to figure out where most of this clipping is getting introduced.

 

As for using clipping intentionally to imitate a very loud real life effect, I don't think it works well unless it's done very skillfully.  The thing is, digital clipping sounds nothing like ear clipping, which involves both mechanical and psychoacoustic mechanisms.  In any case, most of the really loud sounds in real life like jets and rockets are dominated by lower frequency energy, enough that you'll be feeling intense pounding in your body before your ears start distorting significantly.  I'm rather glad movie sound effects aren't as loud as their real life counter parts, but in the interest of realism, I believe getting the bass right goes a long way.  I think the Hell Carrier engines were done well in this respect.  The real life event would likely be loud enough to damage internal organs, but we can suspend our disbelief very well when we hear the same sound as we would from a safe distance.  In the Space Shuttle launch recording I posted, I believe SPL peaked well above 120 dB with the highest energy in the low 20s Hz and the bulk of the energy lying below that.  There is no ear clipping at all, just a lot of pounding bass.

Hey,

Where can I find the space shuttle launch posting?

 

Thanks

Ray

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This turns out to be quite simple on the Marantz:

 

- The subwoofer output clips at 4Vrms.

- MV+Trim must be <=-12dB to keep output below clip level at 4Vrms for a highly unlikely 7.1 signal with 0dB level in all channels.

- No combination of signal and trim causes digital clipping before the output clips at 4Vrms.

These figures are very close to my own observations.  I used the relative input level indicator on my MiniDSP 2x4 along with its published specs to deduce a max output voltage for my Denon of 4.0V rms.  I also installed a few extra attenuators on the line and turned on a sub to hear the clipping.  Right at -3.0 dB from the point at which the output saturated, clipping became audible, and it became much more severe with each 0.5 dB increment.  Having done a lot of computer music in the old days, it sounded exactly like hard digital clipping.

 

What surprises me is that you have to use the minimum trim of -12 to not clip a 7.1 channel digital full-scale signal at master volume "0".  Even then, Audyssey may boost the signal at certain frequencies and still cause clipping.  By your numbers, someone running with the sub trim at "0" and master volume at "0" will clip above 113 dB, which is less than digital full-scale on the LFE channel alone.

 

In my current system configuration, I have meticulously EQed my subs to be as flat as possible across the listening area using my MiniDSP so that Audyssey is not tempted to boost anything too much.  It mostly works, and thankfully soundtracks aren't pushing digital full-scale in all 7.1 channels just yet.  The sad thing about all of this is that all they had to do was give up 2 bits of fidelity (probably at a level way below the noise floor of any realistic listening room) to get back 12 dB more headroom.  If they let you set the trim well below -12 dB, then there'd at least be a work-around.

 

Judging by what I read in other places, I bet some other AVRs are even more headroom limited than the Denon/Marantz.  It'd be nice if review sites could report on stuff like this instead of talking about how much warmer AVR "A" is compared to AVR "B".  Ugh.

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Notes - Have not seen it yet.   It appears to be the loudest film of all time, given its nearly 3 hour run time with those numbers.  It AVERAGES 101.14dB!!!  And it is brick-wall limited at around -0.5dBFS.  In other words, it clips terribly.  As usual, the center channel is the worst offender, followed closely by L, R and LFE.  Surrounds much less so.

 

Shame!  Even at -10, this thing will likely sound very loud and fatiguing.  I gather the theatrical version was quite loud and probably took advantage of the headroom Atmos provides, and then they boosted it further for the home mix.  It's so sad that many of today's headline releases have worse sound than some stuff done in the 1980s.

 

By the way, I recently learned a couple reasons hard limiters at levels just below digital full scale get used:

  • Some DACs behave very badly when presented with digital full-scale signals.  Some may even repeatedly invert the output signal.
  • Lossy compression can sometimes introduce just enough boost to cause a nearly-full-scale signal to become full-scale.  See above.

As such, it seems to be a very good to add a hard limiter somewhere slightly under digital full-scale.

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Hey,

Where can I find the space shuttle launch posting?

 

http://www.digido.com/component/phocadownload/category/15-demos.html?Itemid=64

 

I had to register on the forum in order to get access to the downloads.  I didn't have a problem with that though.  The site is by Bob Katz who is a highly skilled and influential mastering engineer.  He has also been a staunch advocate for high dynamic range in music releases.  His focus is on music, but I wonder if he'd take an interest in the current apparent trend of increasing loudness in home film releases?

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...

By your numbers, someone running with the sub trim at "0" and master volume at "0" will clip above 113 dB, which is less than digital full-scale on the LFE channel alone.

 

Exactly.

With trim at 0, and mv at 0, you will not even get full headroom of the lfe channel alone.

I would think a lot of people run their systems like this, unaware.

 

If this was interesting I think the moderators/other readers would appreciate if this discussion moved to a new thread in the gear section, as it is kind of OT in the bass content thread.

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Sorry - i may have missed the post. I absolutely love CATWS. What are the best bass scenes? (my subs go to 18 Hz -3dB)

Specific chapter times would be awesome.

Keep up the great work - it is much appreciated!

 

http://data-bass.ipbhost.com/index.php?/topic/12-the-low-frequency-content-thread-films-games-music-etc/?p=4146

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Hi - just wondering - are "We were soldiers" and "Shooter" on the list ? They both got some heavy napalm scenes - wouldn't be surprised to see those 2 dig below 20 hz :-)

 

Check the Google Docs linked in the first post for all the "Requests" and what I currently have measured but have yet to post.

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Check the Google Docs linked in the first post for all the "Requests" and what I currently have measured but have yet to post.

Didn't know that - and..... wauw - looking forward to all of those. The exorcism of Emily Rose is also one of my favorites - expect it to score high !

Thx a million for this site and all your work you put into this !

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Check the Google Docs linked in the first post for all the "Requests" and what I currently have measured but have yet to post.

 

I will second that. A big thanks for the guys here doing all the work to reveal content and what's really going on within the audio. Especially Nube/Maxmercy et al.

 

What are your thoughts on Edge of Tomorrow Nube? Getting a lot of rave reviews but won't be out here for a few weeks yet.

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Edge Of Tomorrow sounded great and it seems to be completely unfiltered. There's a lot of sub 20 and even sub 10Hz (which is quite loud) stuff in there. Levels are a bit on the lower side (at least thats what it sounded like to me) but it was a thousand times better than something like Godzilla. And the opening scene was nuts.

 

EDIT: Found out you can delete old attachments, so I can upload some graphs.

(time in filename)

Edge Of Tomorrow:

 

Beginning:

post-1300-0-25853800-1412873030_thumb.jpg

 

Some part of the finale:

post-1300-0-86823500-1412873100_thumb.jpg

 

The new  X-Men had a cool scene too:

post-1300-0-56718000-1412873181_thumb.jpg

The rest wasn't that impressive, levels were on the lower side and it didn't go really low.

 

And while I'm at it a scene from the Godzilla finale

post-1300-0-22929300-1412873317_thumb.jpg

And the flood wave:

post-1300-0-61592900-1412873350_thumb.jpg

 

And Captain America:

post-1300-0-93822400-1412873393_thumb.jpg

post-1300-0-23934400-1412873503_thumb.jpg

post-1300-0-83441500-1412873519_thumb.jpg

 

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Sorry about not posting the latest measurements, but my new job is kicking my ass and they lock down all internet access, so no posts during the day.  I don't even have cell service there...it's like a bunker out at the AFB. 

 

But, fear not, measurements have been made and I'll find time to post in the next few days.

 

EOT good unfiltered bass, haven't watched yet. 

 

Maleficent good unfiltered bass (blew one of my amps on it, in fact, but it's not THAT good...just random amp failure), but only a fair movie if you have kids.

 

gdffgdfgd,

 

For now, just host them on an image site like photobucket, and use the "Image" button at the top to link to the direct URL that the image site gives you for posting, not the IMG tag url.

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Don't want to get carried away here but..... EOT seemed to me to be the real deal. Just watched it and thought bass was brilliant in this. Only my ears to judge but they're still ringing from the assault. Good movie too IMO even after all the glowing reviews. Expectations were high and it delivered. To me didn't seem to be anything wrong with this, bass was powerful and clean but I only have my ears to judge. I think there were scenes in the movie which went pretty low because my subs were moving a lot of air. I loved the opening to the film with that extraordinary bass burst stepping lower incrementally. I know it's been likened to sine waves but I thought it was pretty cool. A real holy shit moment though if caught off guard and lesser subs would surely be cactus if not equipped with some sort of protection. Damn that content was hot why would they do that? Not complaining though. It caused the most excursion I've ever seen on one of my drivers. The other scene which causes similar convulsions would be OHF Washington monument scene although for a longer period. Overall audio was outstanding. Surely Tom Cruise must have some kind of influence given the strike rate WOTW, Oblivion and now EOT. Best's CATWS, which I thought was pretty good. Apologies as I did get carried away in the end.

 

Edit: Just saw the comments regarding being unfiltered so confirms what I thought. Makes it even better!

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EOT get's reference status from me ( this years "Oblivion" ) a flat out 5 anyway you look at it from  sound design , extension ,dynamic range and just the best movie of the year for me!

 

can't wait to watch it again.

 

It sure is reference status but Oblivion audio mix, to me, is more cleaner and EOT is great as well, but, some sounds do get lost within all the action.

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