calibration, schmalibration....

Discussion in 'Archived Threads 2001-2004' started by John Doran, Feb 22, 2002.

  1. John Doran

    John Doran Screenwriter

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    ok. so what's the point of calibrating one's HT?

    as far as i can determine from all of the posts that deal with the topic, the net benefit of calibration seems to consist in simply determining an objective decibel value for the numbers on your volume dial....

    what i have a little more trouble understanding is why you have to calibrate each speaker individually - assuming that the listener/calibrator is roughly equidistant from each speaker, what possible reason could there be for any one speaker to be outputting more or less sound-pressure than any other?

    i mean, is that all it is? a way of compensating for gains and losses of volume from listening-distance? if so, then what about the poor schmoe who sits next to a speaker running hot when he comes to visit and there's no better place to sit?

    can someone help me?
     
  2. Tony Genovese

    Tony Genovese Supporting Actor

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    If this is a serious question (and given the subject title I doubt it), I will try and give you a serious answer. If you were to have 5 speakers that were exactly the same and you sat equidistant from each of them, chances are you would not need to do much calibration. But...in most home theaters, the center is different from the fronts, the surrounds are different from the fronts and center and the subwoofer is different from all of them. Different speakers have different sensitivities, i.e. their output capability given a certain input. These can vary by as much as 21db. To give a ridiculous example, if you had Klipschorns (104db sensitivity) in the front and Celestion SL600's as surrounds (83db sensitivity) if you set them both at 0, the fronts would be playing 21 db louder. You wouldn't even hear the surrounds. And that, in a nutshell is why you need to calibrate your system.
     
  3. Sean M

    Sean M Stunt Coordinator

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    Tony makes very excellent points. Also consider that even if you have five identical equidistant speakers, the room will effect the output of those speakers in those various positions, and so you still need to calibrate at the sweet spot.

    Bottom line, you won't truly understand how much of a difference this can make until you spend the $60 -$70 it takes to buy the necessary equipment, or borrow it from someone, and try it out yourself.

    One more thing: Do you worry about the time alignment errors that the poor schmoe sitting too close to the hot speaker will experience and therefore don't enter delays or speaker distance settings into your receiver or pre/pro?
     
  4. John Garcia

    John Garcia Executive Producer

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    I don't think sensitivity is the reason, but it is a possiblity. If one uses speakers from one manufacturer, from the same family of speaker (which is a very good idea) this should not be an issue.

    You wouldn't listen to your front right speaker set to +50% volume vs your right speaker would you? Well, that is part of the reason. Placement and reflections have much to do with respect to the volume level required for an INDIVIDUAL speaker. For effects that pan front to rear or side to side, etc..., you want the same volume from all speakers to make the effect realistic. You may not realize it, but you will hear the difference, and your brain will tell you that it does not sound authentic.

    What is just as important is getting the distances of each speaker close to what they actually are, so that sounds arrive at the listener with the appropriate timing.

    I consider calibration a "tweak" rather than a must, but I feel it is worthwhile.
     
  5. John Doran

    John Doran Screenwriter

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    thanks for the responses.

    it was a serious question, to be sure - i had been following a thread on powered towers at the end of which everyone was absolutely putting the boots to a guy who hadn't calibrated his HT. i haven't calibrated my HT, either, so i started to wonder whether or not my enjoyment of my system was akin to someone buying a porsche and driving it with booze in the gas tank instead of high octane gas. or something. you know?

    anyway. upon reflection, it came to seem more plausible to me that calibration was the sort of thing you could do to squeeze an extra few percent of enjoyment out of your rig. but that was all.

    by your helpful comments, it seems i was right - in MY system, anyway, there is absolutely NO reason for there to be any (audible) variance in the non-calibrated volumes of my speakers.

    i was just having difficulty understanding why so many intelligent people were treating this guy on the other thread so badly for not having done what seems reasonably understood as a "tweak". at least in some systems. and, of course, if it's a minor thing in some systems, then why not his?

    anyway. thanks again for the help.
     
  6. Michael Mohrmann

    Michael Mohrmann Screenwriter

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    I am sorry, but calling speaker calibration a "tweak" is flat out misleading and wrong. It is not a tweak, nor is it minor, it is part of nearly every (I would say every, but I can't be 100% sure!) HT receiver and processor, and is included as part of the setup within these components.

    Left/right soundstaging, front/back panning, center channel dialogue, loudness contours, etc. all require properly balanced speaker levels. Also, the difference between a system balanced by "ear" and one balanced by a meter can be night and day.

    Michael
     
  7. John Doran

    John Doran Screenwriter

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    michael,

    i completely agree with you. my point is that it seems to me that there is no reason for me to believe that all of my channels aren't balanced, even without calibration. and, by calibration, i mean the exerice using an SPL meter.

    in other words, if the speaker levels are indicated by the receiver to be equal, then further calibration would seem to be reasonably described as a "tweak".

    i guess that's me disagreeing that a system calibrated by ear can differ dramatically from one calibrated by SPL. or at least as it concerns MY system.

    but, i guess i'll never know for sure until i calibrate....
     
  8. ozric_smith

    ozric_smith Agent

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    It's True Nite and Day. Also new speaker change over time, re cal weekly.
     
  9. Brian Bunge

    Brian Bunge Producer

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    John,
    Unfortunately, your assumption is wrong. If you are at all serious about this hobby then proper calibration (using an SPL meter) is a requirement, not a tweak. I'd think if you were willing to take the time and money to research and purchase your system you'd want it to perform to it's fullest. That's all we were trying to tell Bob.
    In case there is any confusion, EACH AND EVERY MEMBER OF THIS FORUM SHOULD HAVE AN SPL METER AND SHOULD USE IT! PERIOD.
    Brian
     
  10. Clinton McClure

    Clinton McClure Casual Enthusiast

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    Also keep in mind that not every receiver outputs the same volume from it's left & right channels. I believe it was Yamaha that had a problem one time of one channel being significantly louder than the other. I know my RX-V995 is unbalanced as far as output on the front left & right. I have to keep the balance knocked a little to the right to get both mains the same volume. If I keep the balance control at 0, the left main is about 8dB louder than the right.
     
  11. BruceD

    BruceD Screenwriter

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    Here is a good example for you;

    I'm sure your room is not an exact mirror image of itself in every direction. That means no 2 speakers will really sound the same at your listening position, because they are reflecting sound off of different wall surfaces and furniture.

    In other words, an SPL meter is a necessity to evenly balance the speakers to a specific listening position in a specific room. No way around it.
     
  12. Tyson

    Tyson Stunt Coordinator

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    Back when I first got my HT, a few years ago, I calibrated everything as best I could by ear (hey, why spend $35 on an SPL meter if my HT "sounds good to me" anyway?). After a couple of years I decided to get an SPL meter just to prove to myself that my setup had been perfect all along. Let me tell you, my setup was not really that close. An SPL meter brought everything in to balance, more so than I had been able to do by "ear". Why "assume" that your setup is correct, when for $35 you can be certain?
     
  13. Dan Hotch

    Dan Hotch Agent

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    Brian, take it down a notch.

    If he likes the sound coming out of his system then that is all that matters.

    I borrowed a very high quality SPL meter and spectrum analyser from work to setup my speakers. I spent the better part of an afternoon setting everything up and had everything calibrated just right... ...then I sat down to watch a movie and the sound coming out of the right rear was noticably/distractingly louder than the rest. Should I just sit and listen to the system this way because the all powerful SPL meter told me it should be set up that way?

    Hell no, I turned it down a few clicks and I am just fine with it that way. Don't try to confuse/intimidate others who are asking for your opinion.

    And another thing, plugging your equiptment into a power source is a requirement, calibrating your speakers with an SPL meter isn't.

    John,

    It is worth while to calibrate your speakers with an SPL meter if only to get a good starting point. If you find yourself waking up in the middle of the night in a cold sweat because you haven't done it yet I think you should go see a doctor though.
     
  14. Brian E

    Brian E Screenwriter

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    Anyone have a link to a thread or a site that explains calibration? I'd like to read up on it before I get my new stuff. Also if anyone can point me to a thread/post that talks about speaker break-in I'd appreciate it.

    Thanks
     
  15. John Doran

    John Doran Screenwriter

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    yikes. ok, ok. i'll do the calibration. maybe.

    but i must admit to remaining skeptical - i have gone through all the test tones on my receiver and they all seem to be the same volume to me, within reason.

    8db, to me, is not within reason; a 10db increase is a doubling in the perceived sound level, and i can tell you that none of my speakers is even remotely twice as loud as any other. though, should i calibrate, i'm sure i will be surprised at just how much difference there is.

    but i must emphatically reject the suggestion that seriousness about HT and audio requires an SPL-calibrated system. i may need to calibrate my system in order to be taken seriously as an HT enthusiast by people for whom SPL-calibration is the litmus test or sine qua non of HT. but that is just not the only way to take HT seriously.

    i might as well say that no one takes HT seriously who doesn't do MLSSA tests on their speakers to measure impulse response and step response and cumulative spectral decay.

    if i enjoy the way my non-calibrated rig sounds, then why is that not enough? even if it turns out that i like it better after i calibrate it, how can that possibly have any bearing on anything? am i not serious about HT just because i would enjoy my system more if i were to dump my mark levinson amps in favor of dynaudio's arbiter amps? i hardly think so. who sets the conditions for membership in the "taking-HT-seriously" club, anyway?

    there's a little too much of dictating terms of other people's enjoyment around here, sometimes. makes it a club i can imagine many people not wanting to join. including me.
     
  16. John Doran

    John Doran Screenwriter

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    dan,

    thanks - i posted without seeing your response.

    - jd
     
  17. Rick Radford

    Rick Radford Supporting Actor

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    Clinton,

    >I have to keep the balance knocked a little to the right to get both mains the same volume.<

    That could be something as simple as room dynamics. In my HT, my LF main runs about 1 to 1.5 dB hotter than my RF main in order to be properly calibrated. In fact, no 2 speakers in my 5.1 setup have the same trim.
     
  18. Brian Bunge

    Brian Bunge Producer

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    Dan,
    You must have done something wrong![​IMG] OK, I'm just kidding. And I agree, I got a little carried away. With all the debate with Bob_A here and on the various fora lately I was only trying to make it clear that everyone should try to calibrate their system using some sort of measurement tool that is more accurate than our ears. And I agree that the Rat Shack meter is not dead on accurate. But like you said, it is a good starting point.
    I still agree that everyone should have one or at least borrow one and see just how close they really were tuning by ear. It's a basic tool and relatively inexpensive. No one should go broke.
    John,
    You're correct. No one can dictate what constitutes a true enthusiast. If it sounds good to you, that's all that matters. My whole point was that if it's possible that your system could sound better, spending the $35 for an SPL meter really isn't much of a risk. Hell, if you don't notice an improvement take it back.
    I apologize for my shouting and hope that you don't let anything I've said (or anyone else around here, for that matter) turn you off from this hobby.
    Brian
     
  19. John Doran

    John Doran Screenwriter

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    brian,

    thanks for the kind words.

    and it would take way more than that to keep from HT...far more.

    take care.
     
  20. Steve Stogel

    Steve Stogel Supporting Actor

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    John, you said, "i might as well say that no one takes HT seriously who doesn't do MLSSA tests on their speakers to measure impulse response and step response and cumulative spectral decay."
    As someone who has done MLSSA tests on my speakers to measure the impulse response and step response and cumulative spectral decay, I can honestly say that HT enthusiasts should absolutely do MLSSA tests on their speakers to....just kidding. I have no idea what any of that stuff means [​IMG].
    As far as calibrating, I think people have gotten a little hot about it around here lately. Yes, you can enjoy your setup without calibrating, and I think the sound can be enjoyable without calibrating. I also think that calibrating should improve the sound (be it a little or a lot) in most HT setups.
    As far as Bob getting the boot put to him by so many members, there is some history there from other posts. But the reason he really got nailed in those threads was the whole point of that thread was that he was going to perform a "test." I think that was why he got so much crap. In fact, when he posted a thread that he was going to perform this test, if memory serves (and it very well may not), some people pointed out that it wouldn't be a good test unless he calibrated, recalibrated, made sure the subs were being fed a mono signal, et cetera. So I think that was the main reason he got picked on so much in that thread.
    As far as his test, I'd like to hear his opinions (or others with powered towers) if he calibrates his system before and after he shuts down a sub. And whether you agree with Bob or not, like Tyson pointed out, there's been some pretty interesting reading in some of his threads.
    Steve
     

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