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Discussion Starter · #1 ·
While considering gain structure needed to properly integrate both -10db and +4db level gear, I began contemplating what would be the single most demanding scene to evaluate operational levels, and clipping thresholds of mixing consumer and pro gear to control, EQ, and power my IB sub.


I'm just beginning construction, however the various threads examining different demanding very low frequency theatrical releases got me thinking. It made me consider what would be a very demanding, the most demanding LFE scene. I can appreciate the recommendations for individual films, however I'm interested in the specific scene, whereby the signal levels would be the highest.


I realize there exists a maximum limit of how hot a specific effect can be recorded at a specific frequency, be it a 17hz. concussive thump from a mortar, or the subsequent 30hz to 60hz. from the mortar exploding. Spectrally, if a scene was densely rich with relatively wide-band LFE, top to bottom throughout the 3hz. to 120hz. spec, the signal would be most demanding of each component throughout the chain.


So, to properly set the LFE/Sub output levels of the AVR or Pre/Pro, and properly set input, and output levels of level shifting gear, DSP and EQs, and finally amplification, one could use a specific scene. That being said, if you could determine the hottest, spectrally wide-band, reference scene, which would scene in which release would you use?


Our family media room is the home of our HT. It's our "daily driver", as all of us use the system all day long. We have two kids, 10 and 14, and no-one has TVs in their rooms, nor do we do any film or television watching anywhere else in the house. We have a TV in another room whereby the kids play their console games, and the occasional standard def DVD. That secondary TV doesn't have any outside source, be it sat, cable, or otherwise.


So, my point is the primary media room, where our HD viewing is done, is used by everyone, throughout the day. So, even the kids operate the system while I'm not around. I'd like to use a reference scene, not only to set operational levels between components, but to set a safe max excursion point that would be highly unlikely to exceed. Even while I enjoy the system, I don't tweak very much. Set and forget, my mantra. I do tweak extensively, to find and experiment with limits, and the effect of different gear entering the system. I learn a great deal from experimentation wrt frequency, the speaker/room interface, etc..


Any thoughts? What's the most demanding scene you know of?


Thank you
 

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Discussion Starter · #4 ·

Quote:
Originally Posted by maxmercy /forum/post/19635781


The -0.5dBFS LFE and Pink Noise tracks on the Audio Test DVD sticky thread....


JSS

Yes, pink noise would work,..but I was looking toward an avenue that someone without any sig gen capability, could utilize as well.


Thanks
 

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You don't need a signal generator, just a DVD player.
 

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Discussion Starter · #6 ·

Quote:
Originally Posted by soho54 /forum/post/19636297


You don't need a signal generator, just a DVD player.

Or an CD player



Sure, and I do. I began with the Stereophile test discs back in the 80s, and man I learn a great deal from those. I've got them all. The Chesky releases were very enlightening too. I also have many other audio test discs since then. Some good stuff.


I got a Rives disc, with the corrected Rat Shack tones, they're limited, but well done and I enjoyed what I learned.


So Flight of the Phoenix, I've not had the pleasure. Anything more demanding?
 

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Well....you asked for it.

From Danley Sound Labs: Fireworks

Foreword on Fireworks Sound File



Well it is probably no surprise to you that I have a fondness for low frequencies and loud noises. If you have heard our speakers, I would like to think maybe its not a surprise that I am keenly interested in reproducing the "stereo image" and realism in reproduction too.


I have been developing a microphone invention for a while now and on the 4th of July, I was inspired to set it up in the back yard at my house to record the Town's fireworks which are set off about ½ mile away. I put the last few minutes of it on a CD and have since played it (to be honest, over and over). It was so much fun, I thought others might want to play this too.


A word of warning.


This recording has a HUGE dynamic range of about 70dB and a peak to average ratio of 40 dB. On the peaks, it is easy to clip things and the spectrum is such that the level at 10Hz is about equal with that at 50Hz (a broad mound around 25 - 30Hz). In other words, this recording can gobble up all the headroom you have and the source is one of the most difficult things to reproduce there is from many aspects. Preserving time and bandwidth critical so also try it on good headphones if your not impressed with it through your speakers.


Anyway, take the file and burn it on to a CD (make a couple copies one after the other) and have fun and approach maximum level carefully.

Best Regards,

Tom Danley
 

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No, maxmercy is saying my Audio Test DVD (w/DD 5.1) has the most demanding DVD content you will find. There is PN on the disk, so you don't need a generator just a DVD player.



EDIT: the Fireworks track is also on the DVD, in the 2.0 Extras menu.
 

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He asked for a demanding scene. Not test tones. Sure, anybody can generate insane test tones. A listener cannot compare them to anything real or know what to expect.


Everybody has heard fireworks. Some up closer than others. If you can crank up your home theater until Tom Danley's recording sounds truly real and like "you are there", you have a mighty fine system.


I have several kilowatts of power feeding quad-amplified high efficiency speakers and a large IB sub. Tom Danley's recording scares me. Give it a try.


Edit: I see you have included it. Great work on that test disk!
 

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Sorry, FOH, I haven't been keeping up. What system did you decide on? IB? What drivers/amp/EQ? How many cubes in the room and how far from the drivers to the LP?


In my current collection, I would have to say that the most demanding scene is the Hulk/Abomination fight scene. Every foot step either of then takes contains a ULF wallop comprised of freqs across the 2 octaves from 3-12Hz and the culmination after the cop car beating is simply brutal:



If you aren't clipping or bottoming after that scene, you are fairly bullet-proof.



Bosso
 

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Quote:
Originally Posted by bossobass
Sorry, FOH, I haven't been keeping up. What system did you decide on? IB? What drivers/amp/EQ? How many cubes in the room and how far from the drivers to the LP?


In my current collection, I would have to say that the most demanding scene is the Hulk/Abomination fight scene. Every foot step either of then takes contains a ULF wallop comprised of freqs across the 2 octaves from 3-12Hz and the culmination after the cop car beating is simply brutal:



If you aren't clipping or bottoming after that scene, you are fairly bullet-proof.



Bosso
I dont know what all the fuss is about WOTWs cuz I agree on this right here, and I find Serenity, Hellboy II, and Wolverine XMen Origins to blow it out of the water as well.
 

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Quote:
Originally Posted by hulkss
He asked for a demanding scene. Not test tones. Sure, anybody can generate insane test tones. A listener cannot compare them to anything real or know what to expect.


Everybody has heard fireworks. Some up closer than others. If you can crank up your home theater until Tom Danley's recording sounds truly real and like "you are there", you have a mighty fine system.


I have several kilowatts of power feeding quad-amplified high efficiency speakers and a large IB sub. Tom Danley's recording scares me. Give it a try.


Edit: I see you have included it. Great work on that test disk!
For what the OP is wanting, though (set up gain structure), test tones wuld give a repeatable, reproducible, very high signal level with which to set gain structure.


JSS
 

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Quote:
Originally Posted by kryptonitewhite
I dont know what all the fuss is about WOTWs cuz I agree on this right here, and I find Serenity, Hellboy II, and Wolverine XMen Origins to blow it out of the water as well.
Krypto,


We need spectrums for these flicks.....please generate them!


JSS
 

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Quote:
Originally Posted by kryptonitewhite
I dont know what all the fuss is about WOTWs cuz I agree on this right here, and I find Serenity, Hellboy II, and Wolverine XMen Origins to blow it out of the water as well.
Haven't seen the Xmen movie to know what it's like, but Hellboy II and Serenity aren't as demanding for me as Flight of the Phoenix. Nor is Hulk 2008. But that's just taking into account the 15Hz bottom end of my tapped horn.


Flight just has these high levels of wide bandwidth LFE during that plane crash that I haven't seen equaled for pushing my TH. It's the only one yet to give me 121dB peaks at listening position, and the barrel roll is perfect for checking the excursion on the Tang Band woofers, since that frequency is precisely where excursion in the horn is greatest.

http://www.avsforum.com/avs-vb/showthread.php?t=834460


That said, Hulk did hit 120dB at LP, so it's by no means a bad choice at all. It's actually #2 on my list of go to demo movies, behind FotP. WotW is #3.
 

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Is the idea here to peak things out on the hottest widest scene assuming that if you left all settings there, you would never have to worry about bottoming out or woofer cooking, clipping, etc?


My plan was to do this with WOTWs, where I must set the sub to -8db, but I find I MUST turn it up to at least -4dB for any other movie, and sometimes above +4.


In a nutshell, i have had this issue of having to set things for every movie, it is taxing and dangerous. But since I have added two more subs it is easier and I am finding almost all DTS movies I start at -15dB master, -4dB sub, and carefully inch up to -2dB... but I can't simply change movies and just leave it.
 

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Right now Im watching Beowulf with master -15, but sub at 0 which is 2 more than usual. Last night Hellboy II I had to turn down to -20 master, when I had it at the usual -15 and sub at usual -3dB it was good, but I had to go +4 IIRC after dropping to -20dB. DVDs I have to turn up more than BluRey.
 

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Quote:
Originally Posted by kryptonitewhite
My plan was to do this with WOTWs, where I must set the sub to -8db, but I find I MUST turn it up to at least -4dB for any other movie, and sometimes above +4.
You're concentrating mostly below 15Hz though... not too many of us have systems to reach high levels down that low. What's best for finding your system's limits is probably not what's best for mine



Personally, I can't do below 13Hz where I live. Too expensive... I can't do IB, I can't afford multiple sealed or ported boxes, and the room itself hates content down that low. The drop ceiling creates a null around 12Hz, and my living area is open to the rest of the house. And since I'm renting, I can't do a thing about it. I just decided 13Hz and down was a waste of my time, got into the tapped horns, and moved on.
 

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when I bottom out its above tuning, so really I set mine to the same movies you guys do. I bet your DTS-10 is comparable to my setup from 10Hz-15Hz then you kick my ass from there on up



I maybe get a whole 5Hz range over you, 5Hz-10Hz? I wish I had REW.
 

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Quote:
Originally Posted by kryptonitewhite /forum/post/19637215


your DTS-10

I wish. The dual Tang Band 8x12 TH is no competition for the DTS-10. I get some 15Hz out of it before excursion runs amok, but that's it... it drops like a rock after that.


Really, I have the low corner a bit too low for those woofers to be ideal. It's more capable than I ever thought it would be, but it has its limitations. The SDX horn will eat it alive.


Anyway, that was my logic for choosing FotP - it should work as a limits finder for most people who aren't shooting for high levels below 15Hz, just because it's so all over the place at high levels during that plane crash.
 

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Quote:
Originally Posted by Oklahoma Wolf /forum/post/19639471


I wish. The dual Tang Band 8x12 TH is no competition for the DTS-10. I get some 15Hz out of it before excursion runs amok, but that's it... it drops like a rock after that.


Really, I have the low corner a bit too low for those woofers to be ideal. It's more capable than I ever thought it would be, but it has its limitations. The SDX horn will eat it alive.


Anyway, that was my logic for choosing FotP - it should work as a limits finder for most people who aren't shooting for high levels below 15Hz, just because it's so all over the place at high levels during that plane crash.

When you first received your 8x12's did you have a small piece of metal in the gap on one while free airing them? If so I remember reading about the begining of your build quite a while back..it's all coming back to me now
 
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