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Discussion Starter · #1 ·
So I've been reading about how this speaker is more dynamic than that and it go me to wondering how much dynamic range there is in a typical action movie. Has anyone measured it, or is there a source to reference this info?

8/12 edit: I've been speaking with MKTheater behind the scenes about dynamic speakers, and I asked him for a good movie scene to test the "oh crap" capability of my own speakers.


He recommended chapter 20 of Batman: Dark Knight on BluRay, in particular, the section of the chapter where a semi truck slams into an armored police van (about 1:16 into the movie).


To test my set-up, I needed a reference point first. At the start of chapter 20, one of the guys in the armored police van says "we'll be like turkeys on Thanksgiving" when they are diverted to lower 5th ave (the 1:15 mark). I measured roughly 76dB on my SPL meter when he says that phrase. Leaving the volume at that setting, when the semi-truck hits the armored van and pushes it into the water (just before the 1:16 mark), I measured a 99dB peak for a diff of 23dB. SPL meter set to C weight and Fast Response.


I also disconnected my sub and replayed the semi-truck slam scene and still hit 97dB, for diff of 21dB. Crossover set to 70Hz. Is the 21dB difference I measured the full range between the dialog and the car crash, or are my speakers compressing the sound?



Anyone have a way to take a feed off of a Blu-Ray player or a prepro to measure the actual difference between the dialog and the crash on the recording?
 

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Digitally recorded media[movies] usually have 20-30db swings, including the LFE. That is signal amplitude, not acoustic output in room.
 

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Discussion Starter · #3 ·

Quote:
Originally Posted by thehun /forum/post/16958782


Digitally recorded media[movies] usually have 20-30db swings, including the LFE. That is signal amplitude, not acoustic output in room.

Thanks for the input. Is that 20-30dB dynamic range from a whisper to a roar, or from average dialog level to a roar? I could have gotten probably closer to 30dB in my test if I were to measure the softest sound to the loudest.
 

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Quote:
Originally Posted by hifisponge /forum/post/16958790


Thanks for the input. Is that 20-30dB dynamic range from a whisper to a roar, or from average dialog level to a roar? I could have gotten probably closer to 30dB in my test if I were to measure the softest sound to the loudest.

From dialog to a roar.


The Dolby meta-data actually encodes dialog level relative to 0dBFS (maximum digital signal) with a 31dB maximum.
 

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Quote:
Originally Posted by hifisponge /forum/post/16958732


So I've been reading about how this speaker is more dynamic than that and it go me to wondering how much dynamic range there is in a typical action movie.

I think "more dynamic" with reference to speakers may be just meaningless marketing-speak. If a speaker is significantly compressing the dynamic range, it would do so via distortion and not by any special linear circuitry, and this would sound really really bad.
 

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Quote:
Originally Posted by Drew Eckhardt /forum/post/16958840


From dialog to a roar.


The Dolby meta-data actually encodes dialog level relative to 0dBFS (maximum digital signal) with a 31dB maximum.

Not exactly (although my description may describe what you meant...)


Included in the Dolby Digital metadata is a term that indicates how loud dialogue is in the program. The measurement, like most digital measurements, is in dB referenced to full scale digital (dBFS.) Most films have dialogue that measures around -27 dBFS. This is, perhaps surprisingly, is the same for Batman or any other film, even a documentary. This consistency results from movie sound mixing facilities world-wide being calibrated to the same loudness. Film mixers don't touch the volume control. They adjust their mix.


Not everything is mixed under these conditions, unfortunately, so the indicated loudness might be different than -27. That value could be as low as -31, but usually doesn't go above -23 or so.


This is normal spoken dialogue, so shouts will be louder and whispers will be quieter, but over the course of a film these will average out. This is an attempt to measure how loud it sounds to the listener, so the measurement is A-weighted.


So, there could be as much as 27 dB difference between dialogue and the loudest sound in a film. This is dependent on the type of film it is (action, drama, comedy, etc.) There is about 100 dB range between the loudest and quietest sounds possible in the Dolby Digital system, but most films (or even real life) don't get even close to that lower level.
 

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Quote:
Originally Posted by hifisponge /forum/post/16958790


Thanks for the input. Is that 20-30dB dynamic range from a whisper to a roar, or from average dialog level to a roar? I could have gotten probably closer to 30dB in my test if I were to measure the softest sound to the loudest.

Yes from average dialog to roar.
 

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Discussion Starter · #8 ·

Quote:
Originally Posted by Terry Montlick /forum/post/16965087


I think "more dynamic" with reference to speakers may be just meaningless marketing-speak. If a speaker is significantly compressing the dynamic range, it would do so via distortion and not by any special linear circuitry, and this would sound really really bad.

There's been a lot of speculation in this thread: http://www.avsforum.com/avs-vb/showthread.php?t=1141168 that speakers with high sensitivity and high power handling will sound more dynamic than your average speaker.


However, in post #93 ( http://www.avsforum.com/avs-vb/showt...1141168&page=4 ) I ask owners of high-sensitivity, high-output speakers to measure the dynamic peaks they hit on a scene out of Batman: Dark Knight. I then compared their levels to the levels I got with my 88dB sensitive speakers. Long story short, we all hit right around 21-22dB peaks on the main channels, but the guys with high-output speakers could play their system at a higher overall level. So they weren't more dynamic after all, they were just louder.
 

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Quote:
Originally Posted by hifisponge /forum/post/16958732


So I've been reading about how this speaker is more dynamic than that

That's marketing-talk that has no formal definition. Follow up on it at your own risk.

Quote:
and it go me to wondering how much dynamic range there is in a typical action movie. Has anyone measured it, or is there a source to reference this info?

Sure you can measure dynamic range, but to do it right you bypass all those complicated and potentially flawed things that might mask dynamic range like speakers and rooms.


Instead, measure dynamic range at the line level outputs of your digital player or better yet, do a digital rip of the sound track of the video, and measure that.
 

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Discussion Starter · #10 ·

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Originally Posted by arnyk /forum/post/16969021



Sure you can measure dynamic range, but to do it right you bypass all those complicated and potentially flawed things that might mask dynamic range like speakers and rooms.


Instead, measure dynamic range at the line level outputs of your digital player or better yet, do a digital rip of the sound track of the video, and measure that.

Yes, that's what I want to know how to do. How would I rip the audio off the DVD or BD, and then what software do you use to analyze it?
 

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Quote:
Originally Posted by hifisponge /forum/post/16969051


Yes, that's what I want to know how to do. How would I rip the audio off the DVD or BD, and then what software do you use to analyze it?


In order to rip a commercial DVD or Blu-Ray disc in the US, you need to break federal law. So, as a good US citizen I can't tell you how to do it.


But, you might surf the web for information from people who live in countries where ripping DVDs and Blu Ray discs is not against the law. What you do with this information is of course up to you.
 

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Discussion Starter · #12 ·

Quote:
Originally Posted by arnyk /forum/post/16969054


In order to rip a commercial DVD or Blu-Ray disc in the US, you need to break federal law. So, as a good US citizen I can't tell you how to do it.


But, you might surf the web for information from people who live in countries where ripping DVDs and Blu Ray discs is not against the law. What you do with this information is of course up to you.

Eh, probably not worth the effort. Besides, if I understand correctly, there is a standard recording level / dynamic range for film, so no need to measure what has already been established.
 

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Quote:
Originally Posted by hifisponge /forum/post/16969051


Yes, that's what I want to know how to do. How would I rip the audio off the DVD or BD, and then what software do you use to analyze it?

Just considering DD for the moment, if you "rip" the soundtrack, you are subject to the somewhat arbitrary (or at least not documented) performance of a potentially unlicensed DD decoder. You could turn off the options in the DVD player that reduce the dynamic range of the audio for the typical living room and use the analog outputs, but why bother?


As mentioned, dialogue in a film is around -27 dBFS. Film audio (and digital audio) can go no higher than 0 dBFS, so that's 27 dB. Your volume control will scale the range, but not reduce it. The ambient noise in your room will set the lower limit, and the digital audio noise floor is much quieter than your room.
 

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Film calibration is max dB at 105 dB (LFE is 115 dB).

Speakers calibrated to -20dBFS, or 85 dB.

Softest sound recorded is 22 dB. Total available dynamic range is then 83dB.

Very, very few residential systems have the ability to reproduce 105dB at the listening positions meaning only a very small minority have (1) actually experienced the full dynamic range available; and, (2) have systems capable of doing so without distortion at the upper end or having the bottom end washed out by ambient noise in the room.


As an observation for those with larger rooms, you cannot achieve full dynamic range at the seating locations with 1" dome tweeters you find on consumer speakers. Well, perhaps, I shouldn't say "never"; but, plan on blown tweeters. To get high frequencies out to any distance, you'd need compression drivers or horns.
 

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Quote:
Originally Posted by Dennis Erskine /forum/post/16969317


Film calibration is max dB at 105 dB (LFE is 115 dB).

Speakers calibrated to -20dBFS, or 85 dB.

Softest sound recorded is 22 dB. Total available dynamic range is then 83dB.

I agree with you in principle, but where did you come up with the "22 dB" number?
 

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While we were the first to be able to record to 0 DC with a flat FR from 0 to 22kHz, there is a playback limit inherent to the noise floor and distortion in the playback chain. While we have built a few rooms which have noise floors to 18dB, very, very few recording and mix environments have noise floors below 20dB. (As I recall the Stag Theater at Skywalker is at 17dB). In the end, attempting anything below 22dB is wasted time, effort and money. I'll need to go back to a dusty stack of standards documents to see if 22dB has been referenced as a standard, however, 22dB is the reference minimum used in quality sound tracks production. Whispers, leaves blowing in the wind, etc. can be at that level. Considerable content is recorded between 22dB and 33dB.


Edit:

There are films which have dynamic ranges in the 105 and greater range. These have included Jurassic Park and the Last Action Hero. I believe this is true with Batman returns; but, I'll need to research that one.
 

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Quote:
Originally Posted by Dennis Erskine /forum/post/16969317



As an observation for those with larger rooms, you cannot achieve full dynamic range at the seating locations with 1" dome tweeters you find on consumer speakers. Well, perhaps, I shouldn't say "never"; but, plan on blown tweeters. To get high frequencies out to any distance, you'd need compression drivers or horns.


The vast majority of people do not have large dedicated HT rooms, so for most people that issue is a non issue. For that matter "large" means different things to different people.


Not too many people even playback at "reference level", but seating distance from the speakers is a (or perhaps is THE) big deal in a larger room. Adding another 6 dB of PEAK output capability can become very expensive.




Quote:
Originally Posted by Dennis Erskine /forum/post/16969317


Film calibration is max dB at 105 dB (LFE is 115 dB).

Speakers calibrated to -20dBFS, or 85 dB.

Softest sound recorded is 22 dB. Total available dynamic range is then 83dB.

Very, very few residential systems have the ability to reproduce 105dB at the listening positions meaning only a very small minority have (1) actually experienced the full dynamic range available; and, (2) have systems capable of doing so without distortion at the upper end or having the bottom end washed out by ambient noise in the room.



"Dynamic range" is a highly misused term. You just did the usual double talk. You add up your numbers and come up with the statement that "total available dynamic range is then 83dB". Those number seem to be a reasonable ballpark as far as the dynamic range that is used (as compared with available maximum) on a DVD.


Your error (in my opinion) is trying to extend that calculated realistic dynamic range that is used on a DVD (AKA 83 dB) to the system peak output capability. 83 dB of dynamic range will scale from a maxiumum PEAK master volume setting of 83 dB SPL on up (with "reference level" calibrated to peak about 105 dB). Only the SPL levels will change, dynamic range will still be the same.
 

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Quote:
Originally Posted by hifisponge /forum/post/16958732



Anyone have a way to take a feed off of a Blu-Ray player or a prepro to measure the actual difference between the dialog and the crash on the recording?


Measurements based on what? Recorded audio levels? In room acoustic playback levels? In room acoustic playback levels adjusted for equal loudness contours?
 

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I think that question was answered early on, ~27dB between the average dialog level and the loudest possible explosion/crash (0dBFS).
 

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Discussion Starter · #20 ·

Quote:
Originally Posted by hphase /forum/post/16969302


As mentioned, dialogue in a film is around -27 dBFS. Film audio (and digital audio) can go no higher than 0 dBFS, so that's 27 dB.
Quote:
Originally Posted by Dennis Erskine /forum/post/16969317


Film calibration is max dB at 105 dB (LFE is 115 dB).

Speakers calibrated to -20dBFS, or 85 dB.

I'm familiar with the above figures, but I'm confused. If you calibrate speaker levels to 85dB, what part of the actual soundtrack will measure 85dB? What is this level referenced to? Apparently it's not dialog, because it sounds like that is supposed to average 78dB. And is the -27dB down from 105 or 115?
 
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