Reference level playback and setup some thoughts and ideas

[lakshman]

here have been lots of discussion on reference level setup in home theaters. here are a few thoughts and tips which i found useful...


first some intro movies are mixed at a reference level of 85 db in a dubbing stage ,these stages have a cinema processor for EQ and volume control.The volume control on a cinema processor is called a fader and its position is relative to the 85 db reference level .it has 10 steps in all and it is setup so that when it is at position 07 , it should give a min output of 85 db at stage channels and 95 db at LFE and peak at 105db for stage and 115 db for LFE.


for THX home theaters we have a zero db which is in fact the fader 07 setting on the mixing stage at 85db spl,in non thx home theater you can try one thing assuming your volume control is in steps like 0-79 or to 100 or whatever.Divide this figure by 10 ,ex if you have volume steps from 0-80 then 80/10=8 steps for every one point increase when compared with a cinema Fader.

this is only on the display,so if you set your system at 75 or85 db based on your test disc ,you should lock your volume during calibration at 8*7=56 points and then run the test tones.once you reach 75 db at that position by adjusting the speaker levels in the setup menu ,DO NOT CHANGE THE MAIN VOLUME CONTROL POSTION at this time you can be sure that when the volume is at 56 on your HT you are playing at reference level or 85 db or fader 07 of the cinema processor.playing a film at volume postion 40 means a cinema fader setting of 40/8=05 .


now some thoughts on the reference level ,all the above is good for setup but bad for playback here is why,firstly very few film makers allow so much dynamic range in their track that you play at 07 fader setting,even in your DVD collection except star wars EP I-III titanic and a few other DVD's you may never be able to play discs at reference level without ear damage ,and many discs i have seen play between fader 03 and 05 for a 2000 cubic feet room.this is due to mixers being forced to make mixes loud and pressure from directors on ever higher levels.


Use your HT wisely and setup your system so that you can match levels in calibration at least with a mixing stage for correct playback of a film mix which mixers spend days perfecting.

[tomdkat]

Originally Posted by lakshman

for THX home theaters we have a zero db which is in fact the fader 07 setting on the mixing stage at 85db spl,in non thx home theater you can try one thing assuming your volume control is in steps like 0-79 or to 100 or whatever.Divide this figure by 10 ,ex if you have volume steps from 0-80 then 80/10=8 steps for every one point increase when compared with a cinema Fader.

this is only on the display,so if you set your system at 75 or85 db based on your test disc ,you should lock your volume during calibration at 8*7=56 points and then run the test tones.once you reach 75 db at that position by adjusting the speaker levels in the setup menu ,DO NOT CHANGE THE MAIN VOLUME CONTROL POSTION at this time you can be sure that when the volume is at 56 on your HT you are playing at reference level or 85 db or fader 07 of the cinema processor.playing a film at volume postion 40 means a cinema fader setting of 40/8=05 .

So, you're saying for a THX certified receiver, set the master volume to 0 and for non-THX certiried receiver, set the master volume to 56?

Also, how does a the receiver being THX Select ceritified vs THX Ultra or Ultra 2 certified impact this, if at all?

Peace...

[lakshman]

i gave an example of 56 you can you can use a higher number as long as it is relative to the fader 07 setting of 85 db.

THX just used a option for setting up systems so that anything less than 0 db would mean -x db below reference mix level.

[Iguana Man]

I don't understand half of this. Nothing against you H-man, it's probably me.

I will second Tom's request (in your other thread) though. Please post in the Your Home Theater thread.