What's the reference level? [Archive] - Audio & Video Forums

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L.J.
10-07-2005, 10:13 AM
I know, I know, I ask alot of questions. How else am I suppose to learn this stuff.

kexodusc
10-07-2005, 10:33 AM
Which reference level are you asking about?
They're all relative, that's why you "refer" to them as a starting point....

L.J.
10-07-2005, 10:52 AM
Which reference level are you asking about?
They're all relative, that's why you "refer" to them as a starting point....

I've read posts where people refered to watching(or should I say listening) DVD's at reference level.

Geoffcin
10-07-2005, 01:36 PM
I've read posts where people refered to watching(or should I say listening) DVD's at reference level.

DTS specs calls out a max SPL of 105db. Sub levels are even higher, with a max level of 115db. Try that with Jurassic Park!

GMichael
10-07-2005, 01:54 PM
DTS specs calls out a max SPL of 105db. Sub levels are even higher, with a max level of 115db. Try that with Jurassic Park!

Jurassic Park at 105db?! Dude, leave the windows open a crack or the sound will make it's own cracks in them.

L.J.
10-07-2005, 02:03 PM
DTS specs calls out a max SPL of 105db. Sub levels are even higher, with a max level of 115db. Try that with Jurassic Park!

I'll have to pull out my SPL meter tonight. Thanks

L.J.
10-07-2005, 02:38 PM
So are these the levels you need to watch a DVD at in order to get the true feel for it?

I do high levels when I'm home alone, but that only happens once or so a week.

Geoffcin
10-07-2005, 03:06 PM
So are these the levels you need to watch a DVD at in order to get the true feel for it?

I do high levels when I'm home alone, but that only happens once or so a week.

Probably the only time you'll see close to 105db is when the T-Rex roars, and even that might be only on the last one in the visitors center.

Woochifer
10-07-2005, 03:14 PM
The THX reference level is 105 db, and that's the level that certified components have to sustain for specific room sizes (the THX Select certification needs to sustain reference levels within a smaller space than the THX Ultra certified components). That's NOT a recommended listening level!

Generally, the recommended listening levels are 75 db to 85 db, and those are also the levels frequently recommended for SPL matching. Getting a "feel" for the DVD is just whatever volume level moves you.

topspeed
10-07-2005, 03:45 PM
Geez guys, that's pretty freakin' loud! I've measured when watching an action flick and even then my peaks weren't much past 96dB's or so.

Geoffcin
10-07-2005, 03:48 PM
Geez guys, that's pretty freakin' loud! I've measured when watching an action flick and even then my peaks weren't much past 96dB's or so.

If you use the adjustment curve you'll see that your probably way over 100dB with the LFE .

Here's a link to the correction values;

http://www.danmarx.org/audioinnovation/rsmeter.html

kexodusc
10-07-2005, 04:21 PM
100dB is too loud for me man, with correction values, I like my peaks in the low to mid 90 dB's, tops...mostly for movies I like between 70 and 85 dB (depending on my mood and the background noise). The odd time higher but I find it a bit much for action intense movies. It's hard to judge. I'll crank dialogue heavy movies, or sometimes really crank the cool action scenes, but if it carries on for any length of time, I like it a bit lower. It always seems louder than theater levels to me...

For music, I'm in the 90's and even low 100's sometimes, but typically I'm in the low 80's again.
I like to hear my phone when it rings.

L.J.
10-07-2005, 04:41 PM
O.K. I have another question. I'll measure this tonight, but I'll ask anyways. When I run the auto setup on my AVR, the volume adjusts to 0.0 for the test tones. I double checked the speaker levels with my SPL meter and they're all set to 80db. So when I watch a DVD and turn the volume to 0.0 does that mean I'm watching the movie at 80db?

GMichael
10-07-2005, 04:46 PM
100dB is too loud for me man, with correction values, I like my peaks in the low to mid 90 dB's, tops...mostly for movies I like between 70 and 85 dB (depending on my mood and the background noise). The odd time higher but I find it a bit much for action intense movies. It's hard to judge. I'll crank dialogue heavy movies, or sometimes really crank the cool action scenes, but if it carries on for any length of time, I like it a bit lower. It always seems louder than theater levels to me...

For music, I'm in the 90's and even low 100's sometimes, but typically I'm in the low 80's again.
I like to hear my phone when it rings.

Here's a nice link that compaires db levels. 100db is very loud.

http://www.myhometheater.homestead.com/splcalculator.html#anchor_13193

L.J.
10-07-2005, 05:13 PM
Here's a nice link that compaires db levels. 100db is very loud.

http://www.myhometheater.homestead.com/splcalculator.html#anchor_13193

I already know I'm going deaf. I go from blastin HT to blastin car audio almost everyday.

Geoffcin
10-08-2005, 02:41 AM
100dB is too loud for me man, with correction values, I like my peaks in the low to mid 90 dB's, tops...mostly for movies I like between 70 and 85 dB (depending on my mood and the background noise). The odd time higher but I find it a bit much for action intense movies. It's hard to judge. I'll crank dialogue heavy movies, or sometimes really crank the cool action scenes, but if it carries on for any length of time, I like it a bit lower. It always seems louder than theater levels to me...

For music, I'm in the 90's and even low 100's sometimes, but typically I'm in the low 80's again.
I like to hear my phone when it rings.

100 dB is like concert level, I don't know anyone who still listens like that at home. However HT is NOT music. Things like explosions and gunshots can easily reach that level, but I think it's just way too fast the ratshack meter to properly read.

kexodusc
10-08-2005, 03:52 AM
I dunno, when I put on some Dream Theater or some hard rock music I like cranking it up to concert levels for the odd song or two. I'm smart enough now not to do it for very long, but I'm sure I damaged my hearing when I was younger.

I don't use the Ratshack meter for measuring SPL levels (I have it just to lend more than anything). Even with the correction values it's not very accurate below 100 Hz or above 10 KHz. I have a cheap Extech meter that's more accurate (but doesn't have C weigthing). I also have a $300 Galaxy Audio meter that is extremely sensitive and accurate. It's great for measuring peaks and average volumes, but it's a bit harder to use than the cheap ones for matching speaker levels.

Geoffcin
10-08-2005, 04:17 AM
I've blown a few fuses in my day. I was just playing some Godsmack a couple days ago and really getting into the woofer movment on these Axiom M80's. It's quite extrodinary!

I wish I had the meters you do. All I have to go on is my analog Ratshack metere, and what I know from going to the shooting range. I've heard handgun reports at close range (120dB), and even with the dialog on resonable levels this Axiom system does a pretty good job of recreating it. I know it's not close to 120dB, but it's a damn sight north of 95!

kexodusc
10-08-2005, 05:21 AM
The GA meter I acquired from my bandmates. Helpful when setting up, but I have to admit, I wouldn't recommend HT enthusiasts go out and spend more than $100 on an SPL meter. Even A weighted SPL meters are fine for setting speaker levels. Below 100Hz the correction values for the Rat Shack meter are good enough, problem is in between the correction values the meter is still off some, and some of the meters will vary a bit anyway. Necessary evil for a meter under $50.
Just assume, the higher the level, the more of an "approximate" reading the SPL meter is giving you.

vxaudio
10-09-2005, 03:17 PM
I usually listen to movies at "reference level" which peaks around 105 db on some movies and on like Lord of the rings dts upt to 115 dB. The way i understand it is that "reference level" is what dolby labs certifies as how loud a movie is in theaters. The way you obtain this is that you set a reference point on your receiver where all the test tones are at 75 dB and I usually make my sub around 85 dB. The test tones are set lower so you dont go deaf setting it. Then when you play a movie..the levels peak around 105 dB or as I said in some movies..110+. another thing i noticed is that on the Nine Inch Nails DVD the listening levels at reference level are like 115 to 120 dB which is way too loud. anyways, I could be totally wrong on what i'm saying, but this is what ive understood it all to mean.

Sir Terrence the Terrible
10-10-2005, 05:41 AM
I usually listen to movies at "reference level" which peaks around 105 db on some movies and on like Lord of the rings dts upt to 115 dB. The way i understand it is that "reference level" is what dolby labs certifies as how loud a movie is in theaters. The way you obtain this is that you set a reference point on your receiver where all the test tones are at 75 dB and I usually make my sub around 85 dB. The test tones are set lower so you dont go deaf setting it. Then when you play a movie..the levels peak around 105 dB or as I said in some movies..110+. another thing i noticed is that on the Nine Inch Nails DVD the listening levels at reference level are like 115 to 120 dB which is way too loud. anyways, I could be totally wrong on what i'm saying, but this is what ive understood it all to mean.

If you truely listen at reference levels, you are going to kill your hearing in a very short time. When I mix soundtracks, I use special earplugs that protect my hearing, but preserve the frequency response of the mix. Levels that peak at around 105db in the mains over a large frequency even for a short duration is not good for the ears.

Dolby and THX established reference level for theater calibration for playback of digital soundtracks. It establishes a level of 85db for the front three channels, 82db for the surrounds, and about 95db for the LFE(reflecting a 10db higher playback over its operating range) Bass management is NOT used in theater sound systems. The pink noise used for commercial theater calibration is about 10db softer than what is used in hometheater theaters.

Most hometheater equipment is not designed for sustain playback levels of over 90db. You should be very careful at setting you system as high as you do(especially your sub) so you protect you hearing while enjoying your movie. It really depends on the frequencies that the loudest peaks are measured. If you are hitting 115db on your sub frequencies(80hz and below) it going to take more exposure before hearing damage occurs. If you are hitting 105db above 80hz, even short term exposure can cause some damage. It is more likely you will kill your sub if it is reproducing bass over 110db. I do not know of many subs that can cleanly hit this level without being close to destruction, especially ported subs.

GMichael
10-10-2005, 05:45 AM
If you truely listen at reference levels, you are going to kill your hearing in a very short time. When I mix soundtracks, I use special earplugs that protect my hearing, but preserve the frequency response of the mix. Levels that peak at around 105db in the mains over a large frequency even for a short duration is not good for the ears.

Dolby and THX established reference level for theater calibration for playback of digital soundtracks. It establishes a level of 85db for the front three channels, 82db for the surrounds, and about 95db for the LFE(reflecting a 10db higher playback over its operating range) Bass management is NOT used in theater sound systems. The pink noise used for theater calibration is about 10db softer than what is used in commercial theaters.

Most hometheater equipment is not designed for sustain playback levels of over 90db. You should be very careful at setting you system as high as you do(especially your sub) so you protect you hearing while enjoying your movie. It really depends on the frequencies that the loudest peaks are measured. If you are hitting 115db on your sub frequencies(80hz and below) it going to take more exposure before hearing damage occurs. If you are hitting 105db above 80hz, even short term exposure can cause some damage. It is more likely you will kill your sub if it is reproducing bass over 110db. I do not know of many subs that can cleanly hit this level without being close to destruction, especially ported subs.

Huh? What? Did somebody say something? Can you speak up?
Can I hear you now?

105db is way too loud for everyday listening. Your ears will never make it to middle age.

L.J.
10-10-2005, 06:58 AM
I measured of the weekend. If I turn my volume to 0.0, my system was hitting peaks around 105db. Even if the meter is off a little, it's still very loud. I usually do -10 for DD tracks and -15 for DTS but I didn't measure at those levels. I'll do that tonight.

I've decided to keep it down. I gotta system in my car and truck, and then there's HT almost everynight. My poor ears. I definately wanna be able to hear 10 years from now.

vxaudio
10-10-2005, 10:42 AM
with crossover at 80 hz and subwoofer off...at reference level the peaks above 80 hz usuallu are around 85 db or so..so most of the really loud stuff is from bass.. i should say in reference to my post above. i usually listen to non action movies with alot of dialouge at reference level, but with action flicks..im usually at the most -10 except on rare occasions. thanks for the posts about protecting your hearing..i will try to take it down a few notches.