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Subwoofer calibration for HT is a pointless waste of time


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#1 of 38 Brian Fellmeth

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Posted May 22 2004 - 07:08 AM

Avia, VE, receiver test tones and sine waves will all give different results. Which is "correct" ? None of them. All of them.

Perfect subwoofer calibration is not only arbitrary but not even possible (in an untreated room). Try this- get the level just right with whatever noise reference source. Then move the meter 6 feet in any direction. Level will change by as much as 10 dB. So the calibration is only valid for one noise set at one point in space.

Besides, even if it was possible to get it perfectly calibrated- what have you acomplished ? You will then hear the amount of deep bass that the engineer mixing the track intended. So what- thats just a person with an opinion- no more or less valid than your taste in level of deep bass for the soundtrack.

The answer is to just let the sub trim float and adjust to taste, movie to movie. If it sounds weak, crank it up a few dB. If its annoyingly over bassy, dial it down. Treat it like the main volume- set where you like how it sounds- movie to movie. Why enforce the sountrack mixer's taste on yourself if you like it more or less bassy ?

Note, the above remarks do not apply to music playback in a treated room and/or equalized subwoofer. Then a flat FR does matter.

#2 of 38 Tony Genovese

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Posted May 22 2004 - 07:50 AM

Thanks for clearing the whole calibration thing up. And to think I've been wasting my time all these years.

#3 of 38 Ned

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Posted May 22 2004 - 08:12 AM

Quote:
So the calibration is only valid for one noise set at one point in space.


True. So make that point your chair. Or do it for 2-3 listening positions and average it out.

Quote:
The answer is to just let the sub trim float and adjust to taste, movie to movie.


Ah, yes. This is exactly the problem you will have when you don't calibrate something. You will constantly be jockeying up/down the level. When you don't calibrate your tv you have the same problem with having to constantly adjust the brightness/saturation/tint for every single movie. It's the same with people who don't calibrate their mains. They'll say "I have to increase the center channel sometimes because I can't hear the dialogue". All of my speakers are calibrated and I *never* have to adjust the center level.

He who calibrates rarely has to adjust.

He who doesn't calibrate will be endlessly adjusting.


All that said. The final level of the LFE channel is subjective. For movies it sounds weak to have it set even with the other speakers at 75db. But I still prefer to know that I'm running 3db hot rather than just guessing.

#4 of 38 Kevin C Brown

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Posted May 22 2004 - 09:38 AM

Yes, then do it by ear.

Or, use a PC, the Radio Shack meter and ...

http://www.etfacoustic.com/
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#5 of 38 ChrisBee

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Posted May 22 2004 - 09:49 AM

Brian

The obvious question is: Why would you want to calibrate for anywhere else but where you normally sit to watch films or listen to music? That you get a different meter reading somewhere else in the room is simply irrelevant.

My RS SPL meter is placed (on a camera tripod) precisely where my head is when I'm sitting in my listening chair when I'm "playing about" with test tones.

Regarding flat settings for music I would agree. I found this could be judged exactly by ear over a range of music well known to me. There was no discernable difference when set by ear from the meter reading taken weeks later when I finally got round to calibrating.

For films my 16-46 gain control is raised two "notches". I have never bothered to test its effect on the SPL meter because it works so well at that setting and fills the room with superb bass effects. Without having artificially high levels of dialogue.

So I suppose I'm agreeing with you. Posted Image

As an aside, but on-topic: Don't you think it's crazy that the average customer of this multi-billion dollar, worldwide AV industry relies on an imperfect $30-40 SPL meter from a cheapo electronics store? Or doesn't bother to calibrate at all? It's like sending man to the Moon with just an Instamatic camera to record the whole event. Posted Image

Regards
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#6 of 38 Brian Fellmeth

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Posted May 22 2004 - 11:31 AM

Ned

Quote:
Or do it for 2-3 listening positions and average it out.


Then your not really calibrated anywhere are you ?

Quote:
It's the same with people who don't calibrate their mains. They'll say "I have to increase the center channel sometimes because I can't hear the dialogue". All of my speakers are calibrated and I *never* have to adjust the center level.


I agree for mains and center

Quote:
All that said. The final level of the LFE channel is subjective. For movies it sounds weak to have it set even with the other speakers at 75db.


In other words, you agree with me- only difference is that you want to know how far you are from "calibrated", and I don't care since the "calibrated" level is arbitrary.

Chris

Quote:
The obvious question is: Why would you want to calibrate for anywhere else but where you normally sit to watch films or listen to music? That you get a different meter reading somewhere else in the room is simply irrelevant.


I don't always sit in the same place and I'm not always the only one listening.

Quote:
For films my 16-46 gain control is raised two "notches". I have never bothered to test its effect on the SPL meter because it works so well at that setting and fills the room with superb bass effects. Without having artificially high levels of dialogue.


My point exactly, we agree, put the meter away for the sub trim.

Quote:
As an aside, but on-topic: Don't you think it's crazy that the average customer of this multi-billion dollar, worldwide AV industry relies on an imperfect $30-40 SPL meter from a cheapo electronics store? Or doesn't bother to calibrate at all?


This seems to be changing. More and more systems are comming with mics and auto calibration routines built in. The technology is caatching up to address this problem.

#7 of 38 steve nn

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Posted May 22 2004 - 01:40 PM

Imo you make a very good point Brian. Maybe not the most politicly correct but none the same. I have found over time myself to be a .1 tweaker. I know where calibration is but on some material it is to much and then on a few others it is to little. Mood and who is home plays a factor along with the listening level. So many variables.

#8 of 38 Steve Schaffer

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Posted May 22 2004 - 01:51 PM

I always sit in the same spot, and any guests I might have won't know the difference so I just calibrate to my listening position. And yes, I do set the sub level about 2 db "hot", but I never change anything to suit a particular movie except the main volume control.
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#9 of 38 Cam McFarland

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Posted May 22 2004 - 01:55 PM

Quote:
I always sit in the same spot, and any guests I might have won't know the difference so I just calibrate to my listening position.


I'm selfish the same way....Posted Image

#10 of 38 Ned

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Posted May 22 2004 - 05:16 PM

Quote:
The answer is to just let the sub trim float and adjust to taste, movie to movie


This is what bothers me about your supposition. I get the feeling that you are changing the LFE level everytime a movie doesn't live up to your expectations.

kaboom... not enough bass, I'd better jack it up and rewind 30 seconds.

KABOOM... woohoo, that was awesome. Hmm, now the music is too bassy, more adjustments...etc, etc.

Soundtracks just vary. If everything always sounded as bassy as everything else you would get tired of it. My favorite theater in Toronto (was) the Uptown. The floor rumbled easily and often. Then I saw this stupid movie called White Squall with Jeff Bridges. The theater shook and rumbled for 2 hours, over and over, the same way everytime. It was totally boring.

#11 of 38 Chuck*W

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Posted May 22 2004 - 06:37 PM

Honestly, Brian, I think you are just trying to yank our chains a bit. But I'll try anyway:

Quote:
Besides, even if it was possible to get it perfectly calibrated- what have you acomplished ? You will then hear the amount of deep bass that the engineer mixing the track intended. So what- thats just a person with an opinion- no more or less valid than your taste in level of deep bass for the soundtrack.


You will have accomplished one of the goals of HT: to recreate as nearly as possible the experience of seeing a film in a theater (sans somebody kicking the back or your chair). And the goal of the theater's presentation? To reproduce for the audience the film the director intended. (The mixer, by the way, works under the direct supervision of the director to help the director realize his vision. And sometimes these guys win Oscars for their work -- so maybe, just maybe, there is some value in listening to their "opinions.")

Quote:
Why enforce the sountrack mixer's taste on yourself if you like it more or less bassy ?


Why not adjust the color of the picture so the people are all green? If you like it that way, feel free. But you are no longer seeing the film that was intended by the artists who created it.

Quote:
Note, the above remarks do not apply to music playback in a treated room and/or equalized subwoofer. Then a flat FR does matter.


Why? Music isn't mixed? I swear I've seen mixing boards in recording studios. Why does that mixer's opinion count for more than a film's mixer? What if someone likes their music "more or less bassy?" Shouldn't they just change the sub's level on a song by song basis?

#12 of 38 Jack Gilvey

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Posted May 23 2004 - 01:29 AM

I only calibrate 'cuz I'm paranoid someone will come over and check. This post has allowed me to relax a bit.
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#13 of 38 steve nn

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Posted May 23 2004 - 02:22 AM

I only calibrate 'cuz I'm paranoid someone will come over and check. This post has allowed me to relax a bit. >>>>>>>>>>>>>




Posted Image Very funny Jack

#14 of 38 Brian Fellmeth

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Posted May 23 2004 - 03:07 AM

Quote:
This is what bothers me about your supposition. I get the feeling that you are changing the LFE level everytime a movie doesn't live up to your expectations.


Quite the contrary. I set it at a reasonable level and leave it there mostly. I'll dial it down a few tics if the windows are rattling, and dial it up f few if I'm showing off the SVS to a visitor.

Quote:
You will have accomplished one of the goals of HT: to recreate as nearly as possible the experience of seeing a film in a theater


Good god, is that your goal ? My system and probably most of the systems owned by people around here easily exceeds the audio performance of theaters, at least theaters in my area. My audio is way beyond my local theaters in every respect.

Quote:
Why not adjust the color of the picture so the people are all green?


Quote:
Why? Music isn't mixed? I swear I've seen mixing boards in recording studios. Why does that mixer's opinion count for more than a film's mixer?


These are different. There is a "right answer" to strive for. In music, there are low frequency instruments delivering notes of variable frequency, sometimes running in and out of the subs domain, that should be of equal SPL and matched to the other insrruments. But even for music, calibration is only really meaningful if the room is treated or multiband equalization is implimented. When some notes jump out at plus 8db and others receed minus 8 dB (hitting modes and suckout frequencies respectively), how could it really matter that the level of noise is matched to withen 1-2 dB ?

Quote:
Why does that (music) mixer's opinion count for more than a film's mixer?


Thats a good question. Because to me, the loudness of an explosion or a crashing wave or a jet engine is just more of a judgement opinion. What a musician does in on a little higher plain.

Quote:
I only calibrate 'cuz I'm paranoid someone will come over and check. This post has allowed me to relax a bit.


Thats the whole point. Jack gets it.

#15 of 38 TimRP

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Posted May 23 2004 - 03:14 AM

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What a musician does in on a little higher plain.

I never got the whole music vs movie differences in audio play back performance, and your statement is even more perplexing since the sound engineer whether mixing for movies or for music will mix the subwoofer either high or low depending on his/her taste 100% of the time. Maybe you can live with the differences in music better than for movies, but to deny that the differences are there is well, not correct.

#16 of 38 ScottCHI

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Posted May 23 2004 - 03:51 AM

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......and your statement is even more perplexing ......
well, i've never described a movie's effects soundtrack as "having soul"? have you?
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#17 of 38 Kevin C Brown

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Posted May 23 2004 - 10:12 AM

I would think that a movie soundtrack mixer/producer/engineer is as serious and tries to be as good at it and as professional about it as a mixer/producer/engineer for a CD or lp or SACD or DVD-A...
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#18 of 38 ScottCHI

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Posted May 23 2004 - 10:20 AM

the soul comes from the musician, not the engineer
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#19 of 38 ChrisWiggles

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Posted May 23 2004 - 11:45 AM

Yeah, calibration is really pointless. I mean why even bother placing your main speakers correctly. Put one in one corner, and put the other in the opposite caddy-corner and point that one at the wall. I mean after all you can't get things perfect ever, so why bother at all?

(angry sarcasm)

Posted Image

If you have a good subwoofer like an SVS, I don't see why you shouldn't calibrate it and work on good placement. Most of the bass freq created by a sub like an SVS won't be affected by room treatments anyway, they will largely be absorbed by the wall structures or exit the room. You can get excellent bass with a properly placed and calibrated SVS. Once calibrated, you can tweak a few dBs to taste after you are familiar with how things are supposed to sound.

#20 of 38 Chuck*W

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Posted May 23 2004 - 06:10 PM

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Good god, is that your goal ? My system and probably most of the systems owned by people around here easily exceeds the audio performance of theaters, at least theaters in my area.


I'm sorry to hear that the theaters in your area are so bad. Most of us need to compromise our audio systems in one big way: the room in which we set up our equipment is sub-optimal. Except for those who are dedicated enough to build a custom HT room, we are stuck with rooms that are the wrong size and shape for ideal acoustics and nothing we do will ever change that. Our rooms are also, on average, noisier than a theater (as I write this my air conditioning is reading 58dB -- it's a little quieter in the living room, but you get the picture -- oh, wait, there's a firetruck going by...). My point is that a modern, THX-certified theater is much better acoustically than most of us can hope for. Not perfect, but better.

And what forums are you reading? I've seen a lot of people discussing $300 receivers and $500 speakers. By virtue of modern technology, those systems can sound terrific, but do you really believe they compare with a theater's sound system in either dynamic range or scale?

Quote:
My audio is way beyond my local theaters in every respect.


In every respect? Can your system fill a 120,000 cubic-foot room with 118dB of sound? Because that would be one respect. Posted Image (Then again, maybe your local theaters can't do that. Again, I'm sorry to hear it.)

Quote:
These are different. There is a "right answer" to strive for.


What right answer? The color and exposure of a theatrical print is set in timing sessions. The timer is just a guy with an opinion. Why should we be bound by his ideas of what the movie should look like? And what, exactly, is the "right answer" when mixing an electric guitar against a trumpet, a kettle drum, and a human voice? It's all judgment calls.

Happily, HT gives us all the opportunity to do it our own way. Some guy can spend weeks calibrating his sub to micro-dB precision only to have the cleaning lady move it so he has to start all over again, somebody else can just crank his up to annoy the neighbors, Brian can get a little box with a big knob and crank the sub up and down all through every movie to prove that he's better than any mixer, and it's all good. Who are we hurting? Ain't technology grand?

And, BTW, I know Brian doesn't do that. I think it would be funny if he did, but I know he isn't advocating anything like that. It was just a joke.


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