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Thread: Turn it up or not?

  1. #16
    RIP 2021 SEAWOLF97's Avatar
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    Quote Originally Posted by Fred Sanford View Post
    Most of my pro amps are labelled as attenuators- actually the Crown DC300A is the only exception, its labels run 1-8.

    je
    But if you can attenuate from 11 they wud be much louder, than attenuating from only 8.

    Quote Originally Posted by BMWCCA View Post
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  2. #17
    Senior Member Fred Sanford's Avatar
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    Quote Originally Posted by SEAWOLF97 View Post
    But if you can attenuate from 11 they wud be much louder, than attenuating from only 8.
    Yeah, I figure with the DC300 only running up to 8, it's probably really a DC450 under the hood if I just modded the volume knobs to turn all the way to 10.

    je

  3. #18
    JBL 4645
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    Quote Originally Posted by BMWCCA View Post
    It's not correct. They aren't gain controls, they are input attenuators. The simplest explanation is you set them so at the loudest level you play your system your pre-amp volume control is in the "sweet spot" around the three-quarters point, and at "normal" level around the half-way point. This question got asked quite frequently on the Crown forum and was answered by a Crown employee and I re-posted it here. Let me see if I can find the thread:

    Here's one mention: http://www.audioheritage.org/vbullet...7&postcount=19

    But I think this is the one I was thinking of: http://www.audioheritage.org/vbullet...0&postcount=19

    Here's the entire "gain structure" reply from the Crown Forum: http://www.crownaudio.com/forums/ind...indpost&p=4628
    This means input clipping? If set too low a level and the input signal music/movie was many times greater for the input it would start to distort. With the volume being at higher level there is less chances of clipping happening.

    BMWCCA
    Those links were very helpful.

    Quote Originally Posted by SEAWOLF97 View Post
    But if you can attenuate from 11 they wud be much louder, than attenuating from only 8.


    that is funny quote "11"

    Nigel Tufnel: The numbers all go to eleven. Look, right across the board, eleven, eleven, eleven and...
    Marty DiBergi: Oh, I see. And most amps go up to ten?
    Nigel Tufnel: Exactly.
    Marty DiBergi: Does that mean it's louder? Is it any louder?
    Nigel Tufnel: Well, it's one louder, isn't it? It's not ten. You see, most blokes, you know, will be playing at ten. You're on ten here, all the way up, all the way up, all the way up, you're on ten on your guitar. Where can you go from there? Where?
    Marty DiBergi: I don't know.
    Nigel Tufnel: Nowhere. Exactly. What we do is, if we need that extra push over the cliff, you know what we do?
    Marty DiBergi: Put it up to eleven.
    Nigel Tufnel: Eleven. Exactly. One louder.
    Marty DiBergi: Why don't you just make ten louder and make ten be the top number and make that a little louder?
    Nigel Tufnel: [pause] These go to eleven.

    I can’t find the old JBL cinema manual in pdf form for the 1993 edition which I have in paper form only.

    JBL 4675
    108db @ 1m
    82db @ 20 meters

    Noise floor
    24db @ 1 meter
    -2db @ 20 meters

    The image is from the 2003 edition

    Crown SPL db calculator
    http://www.crownaudio.com/apps_htm/designtools/elect-pwr-req.htm
    SPL db calculator
    http://myhometheater.homestead.com/splcalculator.html
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  4. #19
    Senior Member 4343's Avatar
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    Cool

    Quote Originally Posted by JBL 4645 View Post
    ...

    that is funny quote "11"

    Nigel Tufnel: The numbers all go to eleven. Look, right across the board, eleven, eleven, eleven and...
    Marty DiBergi: Oh, I see. And most amps go up to ten?
    Nigel Tufnel: Exactly.
    Marty DiBergi: Does that mean it's louder? Is it any louder?
    Nigel Tufnel: Well, it's one louder, isn't it? It's not ten. You see, most blokes, you know, will be playing at ten. You're on ten here, all the way up, all the way up, all the way up, you're on ten on your guitar. Where can you go from there? Where?
    Marty DiBergi: I don't know.
    Nigel Tufnel: Nowhere. Exactly. What we do is, if we need that extra push over the cliff, you know what we do?
    Marty DiBergi: Put it up to eleven.
    Nigel Tufnel: Eleven. Exactly. One louder.
    Marty DiBergi: Why don't you just make ten louder and make ten be the top number and make that a little louder?
    Nigel Tufnel: [pause] These go to eleven.
    When I worked for Snell & Wilcox, one of the lads in engineering had hand-built a noise generator with a knob where the numbers rotated beneath a little window, 1-10 like normal. One day I had it on 10 and noticed that there was an 11 visible after the 10! The potentiometer would not turn that far, so I guess it would need a special "11" pot to get that far...
    Mike Scott in SJ, CA
    Drive 'em to the Xmax!

  5. #20
    Senior Member Fred Sanford's Avatar
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    Quote Originally Posted by Allanvh5150 View Post
    I heard the same argument a few days ago. No professional in thier right mind would run the Power amps attenuators any less than full. One of the linked articals even goes as far to say that if you run the amps on full you will not be able to get any more from the system.... Regardless of the power that is being used, in a live situation there is ample control from a mixer that is running the masters from about halfway to 0. I have run all the amplifiers that I have ever used on full.
    Just as another example, I worked another show with the guys from Southard Audio yesterday(www.southardaudio.com), and all of the amps in all of the many, many amp racks (football stadium show to a crowd of thousands) were specifically pre-set at less-than-wide-open, balanced to get the most from the mixer/crossover/loudspeaker management they were grouped with.

    If any one is worried about amplifier or mixer noise in a live situation they should get another hobby.

    Allan.
    I don't think you'd get much work on Broadway with that philosophy. Professional-level dramatic & musical theater productions absolutely demand silent systems.

    je

  6. #21
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    As the original poster, I believe I get it, running the amps full up decreases the chance of a rare clipping incident while increasing the possibility of floor noise. However when I had my L300s (with a Crown DC300-home system) I was in the habit of running the amp full and having the pre at 1/3 to 1/2 when I was often impressing myself with the L300s punch and clarity. I am now using L166s with another DC300, generally running the amp at 2/3s with the pre at a little better than 1/3.

  7. #22
    Senior Member BMWCCA's Avatar
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    Quote Originally Posted by midlife View Post
    As the original poster, I believe I get it, running the amps full up decreases the chance of a rare clipping incident . . .
    No, running them at full actually has nothing whatsoever to do with preventing clipping. The amp will produce full power regardless and if you set the attenuators correctly you'll actually decrease the possibility of someone coming in and cranking the system into clipping, not the opposite. The noise floor isn't a possibility, it's a reality. Setting the amp correctly in relation to the pre-amp just keeps the noise floor as low as possible.
    ". . . as you have no doubt noticed, no one told the 4345 that it can't work correctly so it does anyway."—Greg Timbers

  8. #23
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    A lot of the power amps that I deal with do not have attenuators. The only time I can think that I would use an attenuator is when I have an amp failure and I need to replace it with somthing larger. Most of the current generation rack gear and mixers have unbeleivable noise figures and so do the amplifiers. Feel free though to do as you wish. I have only been doing live sound reinforcement since 1981 so what would I know. I can't think why I would want any work on broadway though.......

  9. #24
    Senior Member Fred Sanford's Avatar
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    Quote Originally Posted by Allanvh5150 View Post
    I can't think why I would want any work on broadway though.......
    Lots more $/night than the concert work I've done, with lots less lifting. I've dated a few of the pretty dancers, too.

    I have only been doing live sound reinforcement since 1981 so what would I know.
    Interesting- same year as me.

    je

  10. #25
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    Quote Originally Posted by BMWCCA View Post
    No, running them at full actually has nothing whatsoever to do with preventing clipping. The amp will produce full power regardless and if you set the attenuators correctly you'll actually decrease the possibility of someone coming in and cranking the system into clipping, not the opposite. The noise floor isn't a possibility, it's a reality. Setting the amp correctly in relation to the pre-amp just keeps the noise floor as low as possible.
    Not necessarily so. It is not the amp output stages clipping that is of concern but the preamp overloading the input stages and this causing the clipping, just as the master volume is supposed to do on a guitar amp.

    Taken it to the extreme, set the amp at "1" such that you have to turn the preamp up so far that its output will clip the input stage of the amp and the amp will never see its full power.

  11. #26
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    Quote Originally Posted by BMWCCA View Post
    Setting the amp correctly in relation to the pre-amp just keeps the noise floor as low as possible.
    Thats what I thot when I acquired the amp ....in reality, I find that it makes NO difference....its quiet anywhere that its set, and that is after a lot of experimentation.

    The only benefit that I've found to setting the amp lower (more attenuated) is that there is now more granularity to the preamp volume control.

    As for stray hands hitting the volume control on the preamp ?? There are only 2 of us here and she knows better than to touch the stereo.

    Quote Originally Posted by Allanvh5150 View Post
    A lot of the power amps that I deal with do not have attenuators.
    dead-on right....many do NOT have more than just a power switch.
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  12. #27
    Senior Member BMWCCA's Avatar
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    Quote Originally Posted by SEAWOLF97 View Post
    dead-on right....many do NOT have more than just a power switch.
    And many cars have only three, four, or five forward gears, too. Doesn't mean you won't use sixth gear in a car that has one.

    I know we're picking at nits on this now but the original question was about the proper way to use the "gain controls" on a Crown amp. I believe that question has been answered. For those unfortunate enough not to have input attenuators on your power amps, you'll just have to muddle along in blissful ignorance, content that your life is so simple!
    ". . . as you have no doubt noticed, no one told the 4345 that it can't work correctly so it does anyway."—Greg Timbers

  13. #28
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    Quote Originally Posted by BMWCCA View Post
    And many cars have only three, four, or five forward gears, too. Doesn't mean you won't use sixth gear in a car that has one.
    And the first thing one reaches for when they need to put the accelerator down? The gearstick/attenuator. If you are talking about using the attenuators in a home theatre system as safety devices I can see the merit but why not set the internal levels in your amp so that the masters cant run any harder than what you want to be a maximum level. I dont want to have to remember where poweramp levels have to be set when turning a system on and off and I certainly dont want to put marks on the gear where it should be set. I also never mark the desk so I know what channel is what, but that is another subject.

    Allan.

  14. #29
    Senior Member BMWCCA's Avatar
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    Quote Originally Posted by Allanvh5150 View Post
    And the first thing one reaches for when they need to put the accelerator down? The gearstick/attenuator. If you are talking about using the attenuators in a home theatre system as safety devices I can see the merit but why not set the internal levels in your amp so that the masters cant run any harder than what you want to be a maximum level. I dont want to have to remember where poweramp levels have to be set when turning a system on and off and I certainly dont want to put marks on the gear where it should be set. I also never mark the desk so I know what channel is what, but that is another subject.
    I was referring to the fact that the Crowns have attenuators indicating one might want to actually use them. It's not a clutch-shift-throttle analogy, but if you want to play it that way, fine! But it doesn't work even if you consider different final-drive ratios, or whether or not the transmission is an overdrive box, or not.

    And why would you have to move the input attenuators on the amp every time you turned it on? Are you just looking for reasons to disagree?

    Again, the original question was about how to use the attenuators on a Crown amp. If your amp doesn't have them, then by all means don't waste your time contemplating your navel: You just don't have them. If a Crown owner doesn't want to use them properly, then just crank them wide open and have fun using that 1/4 of the range of your pre-amp's volume pot that you'll ever use. To each their own.

    Now if you're just wanting to "buy and argument" in the best Monty Python manner, we'll just have to see how high up on that tree you can pee, won't we?

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  15. #30
    Administrator Robh3606's Avatar
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    I use my input attenuators to help manage the S/N in my active system. When you have compression drivers running at over 110db it certainly helps if you can adjust the amps sensitivity to help keep the noise down. It would be a problem for me if they didn't have them.

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