Silver MemberUsername: Thx_3417
Bournemouth, Dorset United Kingdom
Post Number: 313
Limiting the Armageddon's!
Last night I placed audio limiters on the left centre and right outputs of the Kenwood KRF-X9050D THX select, for the front three screen matching JBL control 5, and performed a pink noise test using the dts test calibration disc, and setting for peak 85dbA in the centre of the room which complies to safety regulations, and a lot more besides the complex film mix and mixes of yesterday and today.
with the1995 hit film "Heat" the mix as some challenging leistering going for it like the Airport scene where the character Neil played by Robert De Niro is running across the runway with the jet airliners in the background on channels left and right with the centre just playing the Foley the footsteps and the panting as he breaths in and out and to hear that over the fronts is not possible without limiting the left and right as well the centre, but the centre is nowhere near the Dynamic level of the mains as the limiter is working fine and helping you to hear all three front channels without straining to hear it, in the Dolby stereo process it's not possible to hear this track with all the crosstalk created by the matrix encoding and decoding but for some home cinemas I bet they sound at there worse and this is my secret to this forum, and seeing it's not really a big secret, but it does work and a little EQ applied to it makes up the differences, if I had a friend over hear leistering to it I doubt he would even know I was using limiters.
And "Heat" 1995 sounds better than before and that bank heist that goes horribly wrong with one of the best weaponry sound effect shootouts I heard in many years still to this day 10 out of 10, also bass response as less distortion or bottoming out the low end, whilst pleasing the listener plays back superfine on this film without too much compromise to the films mix.
TURN THAT BL00DY THING DOWN!
So limiting the sound on all formats Dolby dts and PCM, good or bad well over the years motion picture soundtracks have grown in strength of there Dynamic range capabilities pushing the boundaries to the point of universal excellence, but for those that like the motion picture event to be nothing but short of knocking the soaks of the audiences feet without major complaints, TURN THAT BL00DY THING DOWN!
I for one like it at the industry standard playback level 85dbA but, for those mixers that are getting on an all time high with the works project and throwing everything into it including the kitchen sink for good measures, something as to give + and -!
Peak levels of 85dbA
With peak levels of 85dbA weighting the C weighting is much higher reaching 105dbC weighting on the three screen channels and using this is also applied to the sub bass output for the left centre and right which goes to a multi-channel audio mixer along with the sub bass from the split-stereo surrounds and the L.F.E, which is limited to -10db on the THX select and a little adjustment to the faders on the mixer going to the amplifier driving the JBL 4645 THX cinema approved sub bass with excellent frequency response and range too there is plenty of headroom that I have explored and this takes a beating that can reach 120dbC weighting that's loud!
So I practice 105dbC to 110dbC this depends on the mix and the fader level too, over the next few nights I will be looking more into the Armageddon's whilst making notes on the SPL level meter at a distance from the front 7 feet in a room that's 14xL 10xW 9xH.
As there are so many films now that are pushing the limits even higher, with loud trailers etc, and the Armageddon's of today that have gotten a name for themselves it's no wonder the mixes are looking for Oscar glory.
The mixes on some of only a few well known Armageddon offenders like "Armageddon" 1997 "Twister" 1996 "The Lord of the Rings the Two Towers" 2001 best sound effects, "Star Wars episode 1 1999 and episode 2" 2002 "Alien vs. Predator" 2004 "The Fast and the Furious" 2001 "The Right Stuff"1983 best sound, sound effects, "Indiana Jones and the Temple of Doom"1984 "Mars Attacks"1996 "Star Trek Nemesis" 2002 "Mission Impossible 2" 2000 "Terminator 3" 2003 "Spiderman 2" 2004 "The Perfect Strom" 2000 these are just some of the Armageddon offenders and if I can install audio limiters to keep the safety of it on the ear and the maintain the robustness of the sound system and not the levels in the cinema with an SPL level and adapt this to the home cinema without putting to much compromise on the front stage performance.
In a not ideal world it's impossible to create the sound of a near exploding bomb without the shock of it killing the nervous system!
Human Ginny pig and 7Hz!
So the acoustic approximation will have to do, but for some of us, where pretty bright and if we wanted a killer sound system with an acoustic output of 7Hz at 140dbC weighting that's some 50 sub bass units all with there own amplifier and a 7Hz sine wave tone played at lethal levels of total madness and place a human Ginny pig in the room as part of the experiment where it will match the bodies frequency response and bingo you got someone freaking out on the floor, no thanks I would prefer to enjoy the movie without the bleeding ears!
Anyway does anyone else use audio limiters to make it sound better or worse depending on how you have got it set-up.
It's down to preference, and check out "Heat" the Airport scene and you well start guessing to yourself I like to give this a go, practice makes perfect for the family and friends to without one saying turn it down, when you can say it's limited, go and listen to street traffic sounds!
Get the picture...