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What is "reference level"?

2M views 81 replies 43 participants last post by  Arnkatla 
#1 ·
Having just typed this into "search" on here & having found over 20 pages which really weren't what i was looking for i thought i'd ask - what is "reference level"? That'd be with regards to films & home cinema..

This year i'm hoping to build what should be my final speaker system :T

My idea is simply to design & build a 2 channel system that will produce as little distortion as possible & generate 116db from 20Hz to whatever the poor tweeter will withstand. Yes high frequencies do tend to drop off somewhat so i live in hope. The system will be 4 way active per channel.

As well as this i'll be rebuilding Paradigm's top of the range C5 V2 centre speaker & adding what i'd regard as a driver that can do real bass to it 15" with decent excursion. Poor thing is sitting here in it's box waiting for me to pull it to bits :D

Rear speakers aren't a problem as they'll be much nearer me than the front & centre speakers. Not sure i need to fuss over a sub as a few staff members have put my mind to rest that the LFE is directed to the front left & right speakers when it's set to "off".

So, can someone help me & let me know what is meant by "reference level" when dealing with films etc.

I guess as long as it's less than 116db i have nothing to fuss over as that output would be anechoic & the room will add some gain at low frequencies, at a guess i'm probably looking at 120db+ at 20Hz & 115db at 15Hz with what i'm going to build.

Thanks for your time ;)

Mark.
 
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#57 ·
Re: What is meant by "reference level"?

I can't wait to get hit on the head after this comment.

The way I take it, is the following:

It's the point at which all speakers come together to produce the same volume of output relative to 0.

Example: if my test tone from the receiver (or if you use a disc as this source) is at 80 (can verify the number by looking at the volume on the display in my case, then I calibrate the individual speaker levels with an SPL meter at 75 say, and then 0 is really 75db, not 80. Then, I find, it's not too loud to be at reference (0).

All you AV pros, please be gentle on this. It was trying to oversimplify and generalize... Please add in any technical points so we can all learn how to get better experiences and enjoyment from our equipment without going overly crazy.
 
#58 ·
As an aside...

There is no reference level in 2 channel audio.

The music industry has no real guidelines and this explains the wide volume levels your music is produced at.

In the film industry, the mastering is done at 85db. In the music industry, sometimes they just turn it up to 11.

So, for 2 channel music you will need to keep that volume control handy. :bigsmile:

If you play your music through your HT system then all that balancing the system with pink noise will do is assure you that both speakers are the same volume level. Still very useful.
 
#59 ·
My reference level is far from 90% of the people on here. it is the actual level of being on the stage with the musicians, or in video, the level it would take to convince a blind man the sound was not coming from speakers but was really happening near him. 99% of all systems fail to deliver this. It is called a "reproduction system" for a reason.
 
#63 ·
We just got back from a local Movie theater where I ran an app from my phone that shows the DB levels... It showed peaks of only 90db while watching Robocop. Pretty much the same as what I watch movies at home at.
 
#65 ·
My Onkyo 702 is THX certified. Doesn't make it reference. But for me reference level is pretty much when I can't take it anymore. Everything is almost (important) maxed out.
 
#66 ·
I think reference level is any Level the Director or sound engineer or whom ever is responsible for the sound on a movie, decides it should be and what he finds appropriate for the viewer to experience the movie the way he intended., I do believe that in the movie industry there is certain guidelines as to what it should be, and in order for it to be a THX certified copy that reference level is stipulated at 85 db.

On every THX certified amplifier 0db on the diplay is considered the reference point at which the required 85db volume is achieved but please bear in mind that this is also related to room size and the power required to achieve the required volume in that space hence the reason why some amps are THX I/S plus, THX select (smaller rooms) and THX ultra (for larger rooms) Check THX website for specifics. http://www.thx.com/consumer/home-en...ter/thx-certification-performance-categories/

This does not mean that 0db on every amplifier can be considered to be "reference volume" as stipulated by THX, on a non THX amp this can be anything.

So if you want to find out what reference level is on your amplifier is my suggestion would be to use the test tones on a THX certified disc and turn up the volume on you amplifier until you get a 85db reading on your SPL meter.

my 2c
 
#67 ·
well..., we have stumbled upon a place I feel history is stranger than fiction. The question is "what is reference level", in fact a far cry from how do we measure "reference level". I love 16hz's explanations and I see 16hz is a preferred frequency so I will start at the beginning and hope this includes all instruments..., an important question when considering real sound reproduction and reference sound reproduction.

Well I'll admit I've read every post until page two when I realized we were saying the same thing in deferent words I believe believing we were saying something more..., well...

Let's start at the beginning..., "What is "Reference Level" sound". Come on???? think about it. Wait..., only for a minute. Reference is the sound of an instrument played at its natural reference sound level. So..., but then, a bass drum is louder than a flute when played in chorus and not in refrain or at least, it must be etc etc etc..., or, is it???? Well this is the question. So this naturally leads me to the question what is the loudest natural instrument in the orchestral pit..., played at natural or its normal levels and levels, not within refrains nor at solo intervals. I can only imagine these measure at 75 to 85db for brass instruments, of course depending whether the instrument is one of a reference quality instruments e.g. Stradivarius or the like instrument. In any case, what is this "reference" idea. Well the idea of a reference level is an admirable idea but how do we measure this esoteric idea :foottap:

Now..., moving on, I remember as easy as it is to identify the loudest instrument in the orchestral pit, as a brass instrument,
Well..., Ii would say "the loudest instrument" it must be based in reality at some point and we must adjust other instruments and adjust recording levels to this level..., at some point.

Now, I ask you..., what is this level of optimal play back and in effect optimal recording???????????? Imagine recording at anything less than this optimal reference level....

I'll pause here
 
#68 ·
I only wish that motion picture reference level was the same as orchestral reference level. I generally listen to movies at below reference level because I believe that room size has an effect on percieved volume. 85dB w/ 105dB peaks is just not comfortable for me and my stablemates, even though distortion is at very low levels. BUT. I listen to symphonic orchestral music at levels much higher than I would hear it live in a concert hall outside the first few rows. Why? Because I can, and it gives me a more visceral response. Bruckner and Mahler come to mind. Even so there's no way I or anyone else can realistically reproduce the sound of a pipe organ in a cathedral.
 
#70 ·
It's much less fuzzy and subjective than you are making it out to be. Like you are discussing what the term "fast" means to you, vs the term "speed of sound at sea level."

Movie Reference Level, 0dbFS, is: at the listening position being assessed, the volume level is such that each channel will produce a maximum of 105dB, except LFE, which shall be 115dB.

Now, whether one likes that level or not is another issue.
And even that is complicated. To return to the analogy of speed...
In a 1950s car, going 70mph on a winding road might seem insanely fast and uncomfortable. Your spouse is screaming, "Too fast!" but what she or he really mean is, "Too fast in this car on this road!"

In a 2014 Porsche or similar, it doesn't seem so fast. Tires aren't screeching losing traction, the body isn't shaking and rolling and creaking, the engine isn't straining.

So, is Reference Level too loud for you and yours? Is your equipment and room capable of attempting this without producing objectionable noises and distortion?

For most people, no, it's not capable. And winding road torture test of home theater audio, deep bass in LFE channel, renders no one subwoofer capable of passing.
 
#73 ·
It's much less fuzzy and subjective than you are making it out to be. Like you are discussing what the term "fast" means to you, vs the term "speed of sound at sea level."
Good analogy, eyeleron, terms like "fast" are qualitative rather than quantitative.

Movie Reference Level, 0dbFS, is: at the listening position being assessed, the volume level is such that each channel will produce a maximum of 105dB, except LFE, which shall be 115dB.
Correct, technically speaking (please see next comment).

Now, whether one likes that level or not is another issue.
And that's where house curves come into play. You're probably already using one, if even if you don't know what it is. Ever bump-up the subwoofer level after auto-EQ or manual calibration? Well, you've just created a house curve!
 
#71 ·
Wow ! you guys give me so much to think about. I am now officially terrified to be here. I know so little and need to know so much. I will never even come close to your gear. I hope you all can put up with my lack of knowledge. I love HT though so we have that in common if nothing else. I thought I knew what reference level was. I guess not.
 
#74 ·
Welcome, dreamerpuppy! We were all in your shoes once, and we all have to start somewhere. Please read my comments above. Also, you can check out the STICKY threads at the top of any forum for general info. Glad to have you here, and don't be afraid to ask questions! :wave:
 
#72 ·
I agree with those who have said...

Once calibrated, a surround system's speakers (5.1/7.1/9.1 or 11.1) should be level matched (relative to each other) to 85db (strictly speaking) or 75db (more tolerable/less likely to break something) at the 0 volume position on your pre-pro, processor except for the subwoofer (the .1) which should be 10db higher if your particular sub can achieve that without falling apart at the seams (literally).

Room acoustics, size and layout all play a role in how your system sounds and whether or not it will achieve reference level at the listening position without distortion.
 
#75 ·
Maybe I am oversimplifying this question but I am looking for the easy route to "reference" level. My system includes a Marantz AV7702 Pre plus 200 watt per channel Outlaw Amp plus SVS Ultra 5.2 speakers. Forget the subwoofers for the moment. If I run Audyssey XT32 from my Marantz, it sets the trims and distances for all 5 speakers. The results look appropriate. I then crossover at 80hz.

After having done this exercise, if I turn up the Marantz volume to 0, am I at "reference" level?

Thanks!
Marcus
 
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