# HT question



## fernalfers (Nov 29, 2007)

At what Speaker volume do you guys watch your movies at? It seems the louder i go the better my Center channel sounds. Just curious when you guys watch movies at a loud level where are you at on the receiver dial?


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## bonehead848 (Jan 21, 2007)

haha, I likes it loud! As long as I am not watching at like 1 am or something i keep my hk cranked. It is a much more immersing experience.


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## eugovector (Sep 4, 2006)

There's an actual science about this, it has to do with how your ears are more sensitive to certain frequencies at various decibel levels. Read up on Fletcher-Munson, Steven's Loudness Curves, and others.

Technologies like Audyssey are working to make sure your speaker sound as good (or bad, I guess) at a low volume as they do at a high volume.


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## Prof. (Oct 20, 2006)

fernalfers said:


> At what Speaker volume do you guys watch your movies at? It seems the louder i go the better my Center channel sounds. Just curious when you guys watch movies at a loud level where are you at on the receiver dial?


That depends a lot on the DVD you're playing...and of course your equipment, and the room acoustics..
As an example...I can play Star Wars 1,2 & 3 at -3.5dB..But if I play 4,5 & 6 of the re-digitised versions at that level, then I would probably blow my eardrums...The highest I can go with those is -9dB.
For most other DVD's..-8dB..


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## salvasol (Oct 31, 2006)

Prof. said:


> That depends a lot on the DVD you're playing...and of course your equipment, and the room acoustics..For most other DVD's..-8dB..


:rubeyes: That's to loud Prof. :bigsmile:

I agree that the volume depends on the DVD material ... I play most at -15dbs :crying: (volume dial is a little over half I think, volume is from -80db to +16.5db):whistling:


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## Prof. (Oct 20, 2006)

salvasol said:


> :rubeyes: That's to loud Prof. :bigsmile:


And that's in a room just 10' x 15'..:bigsmile:
But the room is virtually acoustically dead, and it takes a bit of power to stir things up..


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## drf (Oct 22, 2006)

Are you guys quoting the figure on your volume dials? These are not exactly compareble are they?

-15dB one one system could result in the same room spl as -9db on another :scratch:


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## Sheep (Feb 16, 2008)

Movies and films are monitored at 85dBC(Hence the saying 85dB reference volume). So if you want it to sound how the engineer intended it, that is probably the best volume to use. As stated earlier, the human ear has a different frequency response at different volumes, and Fletcher Munson plotted these, showing that roughly 85dB is the optimum for playback. Anything higher will have a 1-4KHz emphasis and anything lower will have a loss of low end.

HTH,
SheepStar


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## Prof. (Oct 20, 2006)

drf said:


> Are you guys quoting the figure on your volume dials? These are not exactly compareble are they?


That's very true..If I put a different AVR in my room, then I would probably have different figures..
Also the efficiency of the speakers will affect volume levels required for optimum listening level..


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## Prof. (Oct 20, 2006)

Sheep said:


> Movies and films are monitored at 85dBC(Hence the saying 85dB reference volume). So if you want it to sound how the engineer intended it, that is probably the best volume to use. As stated earlier, the human ear has a different frequency response at different volumes, and Fletcher Munson plotted these, showing that roughly 85dB is the optimum for playback. Anything higher will have a 1-4KHz emphasis and anything lower will have a loss of low end.
> 
> HTH,
> SheepStar


Does this figure of 85dB refer to an averaged listening level of any DVD?...
Considering the dynamics we hear in some movies,and as to the type of sound source used, this could vary considerably, depending on how much dynamic is set on the AVR..
Or does it refer to peak levels? 
I'm sure some of my peak levels exceed 85dB.!!

I certainly hope it doesn't refer to lowest level sounds...


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## Sheep (Feb 16, 2008)

From what I was taught, the average level is 85dB. Obviously peaks will go over that, otherwise play back would be pretty boring!  

The 85dB rule is mainly a general practice, most proper studio's use this. Apparently it used to be 75dB, but has since been upped to 85dB. However, there is good chance other studio's might go about this differently. I would still use 85dB based on what Fletcher Munson found.

SheepStar


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## Prof. (Oct 20, 2006)

So it's the averaged level...So how would one set that level for any given DVD, considering that there are variations in output level between one DVD and another!!?

I'm not saying you're wrong, but I can't see how one would know what the average listening level is for a particular DVD, considering the huge variations in output level..without using an SPL meter all the way through a movie and then averaging the different levels..
And that would apply to that movie only..


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## Sheep (Feb 16, 2008)

I would use a test tone. Find out what rating on the volume control is 85dB and use that. It would be impossible to calibrate it with a source that varied in volumes as much as a movie. Ultimately you can't have it at 85dB all the time, but you could easily find the average.

SheepStar


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## salvasol (Oct 31, 2006)

Sheep said:


> I would use a test tone. Find out what rating on the volume control is 85dB and use that. It would be impossible to calibrate it with a source that varied in volumes as much as a movie. Ultimately you can't have it at 85dB all the time, but you could easily find the average.SheepStar


I think we already did this, Right??? ... (When we calibrated the system, using the autocalibration, internal test tones or DVE/AVIA disc) :huh:



> ...Are you guys quoting the figure on your volume dials? These are not exactly compareble are they? -15dB one one system could result in the same room spl as -9db on another


You're right!!! ... every room is different :yes: ... I was just trying to make a joke to the Prof. about the volume he uses ... :bigsmile:


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## Prof. (Oct 20, 2006)

I find this figure of 85dB. quite incredible, considering that we've set our fronts to 75dB. with the volume set at 00 to obtain that SPL reading...

Even at that level, if you played a DVD it would be ear shattering, little alone playing it another 10dB. higher...

Am I missing something!!.?


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## Sheep (Feb 16, 2008)

salvasol said:


> I think we already did this, Right??? ... (When we calibrated the system, using the autocalibration, internal test tones or DVE/AVIA disc) :huh:


Yes, but what volume was the receiver at when you calibrated? Using that volume will give you 85dB average (using a test tone). 

SheepStar


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## no. 5 (Jul 4, 2007)

Prof. said:


> I find this figure of 85dB. quite incredible, considering that we've set our fronts to 75dB. with the volume set at 00 to obtain that SPL reading...
> 
> Even at that level, if you played a DVD it would be ear shattering, little alone playing it another 10dB. higher...
> 
> Am I missing something!!.?


Well, 85dB is the reference level for calibration production studios and theaters; the full range channels are all calibrated so that a -20dBFS input will result in 85dB of sound pressure, if memory serves, the test tones on AVAI and DVE are at -30dBFS.


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## salvasol (Oct 31, 2006)

Sheep said:


> Yes, but what volume was the receiver at when you calibrated? Using that volume will give you 85dB average (using a test tone). SheepStar


When I did the autocalibration (Yamaha RXV-2700) the volume was set at "00" ... then I manually checked with RS meter with the receiver internal test tones and SPL was 75 :yes:

I used DVE ... to get 75db the master volume was @ -5db :scratchhead: ... I think because I used DTS on the DVE DVD :dontknow:


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## tonyvdb (Sep 5, 2007)

Just to clarify Reference level is still 75db but THX recommends 85db with peaks of 105db and 115db from the LFE channel with the receivers volume level at 0db.
Pink noise is the only true test tone that you can use to manually set reference level. with the exception of Avia most audio and DVD setup disks, the pink noise is set for 75db (Avia is set for 85db) Reference level is the db level that is at your listening position with all speakers running so in a large room with your listening position just behind the center of the room this will seem louder if you are close to the speakers. 

Reference level is not as easy to achieve as you might think, most center channels for example can not maintain the peaks of 105db particularly if your sitting 12ft away as the farther you sit from the speakers the more db's you need to get out of that speaker to reach your ears at 85db. For example a speaker with a sensitivity of 90db will need 250watts to give you an SPL of 105db at your listening position if your sitting 12ft away. Can your speaker handle that?
So the bottom line here is that reference level is not easy to achieve and in most situations will cause distortion at the peak levels stated above unless your system is fairly beefy.


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## Sheep (Feb 16, 2008)

Yeah but... 105dB will cause hearing damage after prolonged exposure. The average is 85dB, not 105dB.


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## drf (Oct 22, 2006)

tonyvdb said:


> Just to clarify Reference level is still 75db but THX recommends 85db with peaks of 105db and 115db from the LFE channel with the receivers volume level at 0db.
> Pink noise is the only true test tone that you can use to manually set reference level. with the exception of Avia most audio and DVD setup disks, the pink noise is set for 75db (Avia is set for 85db) Reference level is the db level that is at your listening position with all speakers running so in a large room with your listening position just behind the center of the room this will seem louder if you are close to the speakers.
> 
> Reference level is not as easy to achieve as you might think, most center channels for example can not maintain the peaks of 105db particularly if your sitting 12ft away as the farther you sit from the speakers the more db's you need to get out of that speaker to reach your ears at 85db. For example a speaker with a sensitivity of 90db will need 250watts to give you an SPL of 105db at your listening position if your sitting 12ft away. Can your speaker handle that?
> So the bottom line here is that reference level is not easy to achieve and in most situations will cause distortion at the peak levels stated above unless your system is fairly beefy.


how did you calculate that? using this calculator I got 101.7dB at the listening position using 2 speakers with a sensitivity of 90dB and a 50w amp.

Most amps that can supply enough power to maintain 85dB average will easily handle peaks at 105dB.


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## atledreier (Mar 2, 2007)

So what would I need to calibrate to when running one speaker at a time?

I'm running a pink noise signal from one speaker at a time. What should I see on the RS meter (assuming no peaks here) when running that noise? I have no means of running all channel pink noise to calibrate to 85dB.


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## tonyvdb (Sep 5, 2007)

Sheep said:


> Yeah but... 105dB will cause hearing damage after prolonged exposure. The average is 85dB, not 105dB.


If you read my entire post I said peaks of 105db.


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## tonyvdb (Sep 5, 2007)

drf said:


> how did you calculate that? using this calculator I got 101.7dB at the listening position using 2 speakers with a sensitivity of 90dB and a 50w amp.


Your link is not working drf, and I am sure that that reading is at the speaker position not at the listening position of 12ft away because that is the reading that you would get at the speaker. A room with a seating position of 12ft from the display is quite large and a 50watt amp will not power a speaker easily to fill a space that large to 85db with pink noise let alone 105db peaks. Remember that 85db is allot louder than most people think and 85db of pink noise is very annoying. You would have to yell to be heard over it.


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## hyghwayman (Jan 15, 2008)

drf said:


> how did you calculate that? using this calculator I got 101.7dB at the listening position using 2 speakers with a sensitivity of 90dB and a 50w amp.
> 
> Most amps that can supply enough power to maintain 85dB average will easily handle peaks at 105dB.





tonyvdb said:


> Your link is not working drf,


Here is the link, I fixed it:jiggy:.
SPL Calculator

It's what I do/did for a living (fix things),
hyghwayman


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## tonyvdb (Sep 5, 2007)

Hmmm, Thats interesting something seems off. I dont see how a center channel speaker at 50watts can produce clean db's at those readings at a seating position of 12 ft in a room that would be at a minimum of 14'long x10' wide with furniture and carpet. 95dbs of pink noise is very loud for a singal speaker to produce.
Anyone have any input on this?


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## PT800 (Feb 19, 2008)

As has been said it depends on the source, and receivers/amps being used, and the size of the room.
I'm using a Parasound 220wpc amp for 5 channels and the HK receiver drives the back channels.

For the subs, I use a Crown K2 amp(800wpc). The two main subs(4 ohm) are wired in parallel to one side of the K2, so the amps "sees" 2 ohms, thus 2500w total. Those subs are at the main L/R locations.

The other side of the K2 has a pair of JBL L55s(LE14A woofers) wired in series, as they are only rated at 150w/ea, so I figure they're getting 200w/ea. Those subs are located at the mid-points of the side walls, as per the Harman White Papers, which even out the sub response thoughout the entire room.

So in a room that is 3130 cuft I have a total output of 4080w. For most source material I have the HK volume set around -17 ~ -20db. I calibrated the system to 75db/channel with the volume @ -20db. That puts the average db level, at the center seat, to about 85db, on movies.

If I'm watching concerts on HDNet, then the volume is usually around -9 db, as HDNet's volume is much lower than the other movie channels.

For SACD or DVD-A, though the bypass mode, the volume is more like -30db for most of those recordings.


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## Sheep (Feb 16, 2008)

tonyvdb said:


> If you read my entire post I said peaks of 105db.


I did. But you said "can your speaker handle that?" making it sound like the 105dB was constant.

SheepStar


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## Prof. (Oct 20, 2006)

atledreier said:


> So what would I need to calibrate to when running one speaker at a time?
> 
> I'm running a pink noise signal from one speaker at a time. What should I see on the RS meter (assuming no peaks here) when running that noise? I have no means of running all channel pink noise to calibrate to 85dB.


The standard method of setting individual speaker levels, using the signal generator on your AVR, is to first of all, set your meter to C weighted and slow..
Set your volume control to "00", and adjust the individual AVR volume tabs to read 75dB. on the front three speakers..

If you want your sub to run a bit hotter..set it about 4dB. higher..

Surround speakers can be set to the same as the fronts, unless you have dipoles...They can be set a bit higher than the fronts to give a better balance between front and back..

I hope that helps..


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## atledreier (Mar 2, 2007)

Ok, so if I set my individual speakers to read 75dB, I will have 85dB if all are running? how do you do the math on that? 

I thought you get a 6dB increase (theoretical)if you add another speaker for the same signal? Even if you figure only a 3dB increase per speaker you would end up with 75dB+(4x3dB)=87dB?


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## drf (Oct 22, 2006)

tonyvdb said:


> Hmmm, Thats interesting something seems off. I dont see how a center channel speaker at 50watts can produce clean db's at those readings at a seating position of 12 ft in a room that would be at a minimum of 14'long x10' wide with furniture and carpet. 95dbs of pink noise is very loud for a singal speaker to produce.
> Anyone have any input on this?


I think confusion of power requirments is more the result of marketing and, dare I say it, one upmanship. How many times do you see everyday units with ludicrous power ratings stickered all over them?

For the average size room 4x6 metres (12x20 feet) the total power needed for a decent spl is not as much as most would assume. I used to use a 200Watt 2 ch. and 2x100W thinking I need 400Watts per side for 2channel home use until I took some measurements and did the mathes. I realised although I had 400W at my disposal I was only using 40Watts on average. I am currently using a pitiful 20 Watts per side in 2 channel and am loving every minute of it. I do generally recommend at least 100W so you have some headroom, but depending on the situation a carefully planned system will use a lot less. 

I maybe wrong of course, but I know what I like, and I know what I measure.


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## atledreier (Mar 2, 2007)

drf said:


> ... I was only using 40Watts on average...
> 
> ... I do generally recommend at least 100W so you have some headroom, but depending on the situation a carefully planned system will use a lot less...


40watts on average might be fine until that time where you need those 3dB headroom. I'd rather have that 400W amp running at -10dB than the 40W at 0dB.. I'm pretty sure that 40W sounds strained at 0dB.

i like the peace of mind I get from knowing that I have power on tap if I should need it. I hate having to mind the volume control and check if it's at -10 or -11 because at -10 my system will blow up.


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## thxgoon (Feb 23, 2007)

I'll chime in a bit here to see if I can help.

When a recording is made a 'master' level is set and everything is recorded under this. So recordings are made on a scale from 0db to -(infinity)db. On this scale you calibrate any of these systems such that 0db results in 105db at the seating posistion. Thus a -30db test tone or signal results in 75db and a -20db signal results in an 85db sound at the seat. This is if everything has been calibrated at the seat in the room. Using these methods virtually every stuio, movie theater and home theater will have the same levels with the same content.

I don't know how you would 'average' the levels in a film. This would require some pretty intense math and computational power and I don't think there is really a need for such a spec. When the recording engineers sit down they set levels where they think it is needed to convey what is happening in the scene. Obviously some movies are very loud and some are really quiet. It's all up to the film makers and they use this calibrated scale to make sure the stories are told the way they intend them to.

This plot shows some measurements I did a while back to see for myself just how much loss there is from the speaker to the seat as this is a grey area. It averages about 6db or 4X power. Taking this into account, 90db speakers should take about 100 watts to reach a 105db peak. And these peaks are usually very short lived and most amps have some headroom above their rated power.


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## drf (Oct 22, 2006)

Thanks THX, what distance was the seating when you measured? 



> 40watts on average might be fine until that time where you need those 3dB headroom. I'd rather have that 400W amp running at -10dB than the 40W at 0dB.. I'm pretty sure that 40W sounds strained at 0dB.


To get the extra 3dB out of a system like this you'd only need 80 Watts, which is why I said I usually recommend 100w, and as thxgoon has pointed out 100w for 90dB speakers is enough to peak at 105.


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## PT800 (Feb 19, 2008)

atledreier said:


> Ok, so if I set my individual speakers to read 75dB, I will have 85dB if all are running? how do you do the math on that?
> 
> I thought you get a 6dB increase (theoretical)if you add another speaker for the same signal? Even if you figure only a 3dB increase per speaker you would end up with 75dB+(4x3dB)=87dB?


While watching a movie on my system the normal level is near 85db, at the center seat. That's watching a db meter go up and down. Of coarse, things like thunder, loud bass notes, and the like, will jump it way up.
But the source has something to say about it. Like I said before, HDNet seems to have a lower volume, at least for concerts, than other movie channels. So at a -20db the actual volume varies from channel to channel.
But in a 5 or 7 channel system each channel is producing a different signal. Its not like stacking a pair of mono subs where you gain 6db, compared to a single sub. So the total increase will be a bit less.


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## atledreier (Mar 2, 2007)

But if you run a pink noise signal to the left front speaker, and measure the spl. For a given Master Volume setting you get 75dB. Then add the right front, with the same signal. In theory you should gain 6dB, right?


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## drf (Oct 22, 2006)

atledreier said:


> But if you run a pink noise signal to the left front speaker, and measure the spl. For a given Master Volume setting you get 75dB. Then add the right front, with the same signal. In theory you should gain 6dB, right?


That would depend on the total effeiciency of each speaker + room interaction. It would not be inconceivable to get more than 6dB when you factor in room gain. Another posibility is that if you only have one driver in each speaker then the addition of the right channel would only give you 3dB.


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## thxgoon (Feb 23, 2007)

PT800 said:


> Like I said before, HDNet seems to have a lower volume, at least for concerts, than other movie channels. So at a -20db the actual volume varies from channel to channel.


To make things even more confusing Dolby Digital has a feature called dialog normalization built into it where the producers can bump or lower the over all volume of the show without you having to change the volume knob and without them having to re-record everything all over again. The intent is such that the quiet movies on tv will be loud enough and the loud ones soft enough that when channel surfing or input switching everything is at the same relative level. IMO this is rarely implemented properly in broadcast.

drf - I think my couch is 12 feet away but I don't remember exactly. I measured the first one 3 feet from the speaker and I chose the speaker that was the furthest from any room boundaries to get a worst case senario.


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