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Driverack 260 gain structure question

kevinjameskevinjames Posts: 2
Hi, first time poster with a question about setting input and output gain levels.

With the gain input jumpers set to the factory default on the DRiverack 260 how high do you guys recomend to let the signal hit for the inputs and outputs? It looks like it doesn't hit red until +18dbu, but is it ok to let the incoming and outcoming level hit that high and then back it down just enough to where the red +18 light doesn't come on (so like +16 or +17)? Or is it better to keep it so it barley lights the +12dbu or even lower at +6?

I am trying to dial the gain structure in for my system but due to circumstances beyond my control I am not able to hook any speakers up to the amps to check for audible distortion. My neighbors hate me and I'd have the cops at my door in about 2 minutes flat. I can always fine tune later but I'm looking for a general starting point.

I know you can change the input jumpers but the manual says that once you chnge the factory setting the output meters will not be calibrated so I don't want to change the jumpers.

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    GadgetGadget Posts: 4,915
    Hi
    In a gain structure setup we are trying to get all the equipment on the same page. This is accomplished best by getting all the equipment to clip @ the same point. This way, if one piecer of equipment has a lesser gain before distortion that another piece we are working within the most linear portion of that equipments abilities. If the mixer clips @ +28 db so be it, just get the mixer to just clip, then the inputs and outputs of the driverack so they just clip. If the speakers you are active use the suggested setting for them (the MFG's setting).

    One beauty of the digital domain is that the signal to noise ratio is not as big a factor as it is in the analog domain. its much more tollerant than in the analog domain, so we don't HAVE to put the signal to such a high level to get the best sound. That said there is one more factor that is an 'absolute'. DIGITAL clipping is VERY BAD, and sounds terrible! while analog clipping isn't such a bad thing, and is sometimes even desirable, and I'm not talking about a power amp here but as in a warm clipped analog tape recrding., generally called 'saturation'. You can't do that with digital... so if there is any chance of clipping the signal in the DR its best to lower the level so it doesn't.

    Once you get the gain structure dialed in you will need to make compromises @ the amp/speakers to ballance the sound from low to hi. Just remember to never exceed the level we set in the gain structure, and if you simply have to make adjustments to the crossover gain, you will also be changing the crossover point, so remember that.

    There should be no reason to change the jumpers, but it has also been my experience that the meters are also not 'calibrated' all that well anyway...

    gadget
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    OK I understand that but maybee I didn't put the question the right way.

    What I meant was this. The input and output meters go from green and turn orange at +18, then they turn red at +22. So wich point is considered clipping, Orange (+18) or Red (+22)?
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    GadgetGadget Posts: 4,915
    why +22 of course! 8) my mixer is +28 :shock: ...Red generally indicates the onset of clipping :( ...in the analog domain this isn't a bad place to be :D ... in the Didital domain ANY red :oops: is considered devistating :shock: ! Digital clipping is definatly NOT PRETTY. :x

    The idea is to get all the equipment to clip at the same point... tha way a clip light on ANY piece of equipment is equal to a clip @ any stage of the system :!:

    The benefit of this is it gets the systems various pieces of equipment, with their various headrooms, into their most linear range's.

    gadget
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    OK, then if the red light at +22 on he Driverack is the threshold of clipping, then is tht the analog clip point or digital clip point?

    I am very aware of the difference in sound between analog and digital clipping but I am not sure which of the 2 this +22 red light is indicating.
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    GadgetGadget Posts: 4,915
    Well, I assume (I could find out... if you really must know) but according to the block diagram, its post mixer, and judging from the fact i have seen hard red and no \"digital trash\" it leads me to believe its pre- A/D or calibrated to avoid this eventuality (I have never heard harsh sound from a DR at all). I do however suggest a good gain structuring and avoid clipping to the tune of 6-12 db of headroom before clipping @ any stage...

    Gadget
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    Ok well what do you think about this then.

    My system is for dj use only and I rent to promoters who book 3rd party dj's (ie I'm not affiliated with the dj's) We all know that dj's don't usually have a clue about why its bad when the dj mixer is hitting in the red and they generally don't listen when you tell them to turn down the gain.

    I understand about setting gain structure that the whole point is to get evrything to clip at the same point, and then set the output limiters so the amps will not clip at this level and then back evrything thing down to just before clip point but what if you know going into the event that the dj's will most likely be redlining the mixer all night? Would you still set the gain structure the same way?

    The reason I ask is that in a perfect world the mixer would always be run by someone who is not going to let the mixer clip, and there for with everything set to clip at the same point that means if the mixer isn't clipping, nothing will be clipping. Thats not the case for me I know going into it that nomatter how I set the gain on the mixer the dj is going to red line it. Always . As in every time because they just don't get it and don't care.

    So taking that into consideration would you still set EVERYTHING to clip at the same point?
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    GadgetGadget Posts: 4,915
    Yes, and then you set the 260's brick wall limiter, and LOCK THE SON OF A BITCH :lol: so they CAN\"T exceed the point you set in the DR :wink: You see we still need to get all the equipment into the most linear part of their signals, and the gain structure is the only way to optomize that aspect . Note: I'm not proposing you leave them @ that point, I'm suggesting you back the mixer down 6-12 db minimum for headroom. I have as I said, 28 DB over -0- VU, and I seldom see that -0- vu durring even a live show (the system does tripple duty Live, karaoke, and DJ...

    The 260 has multi level password encoding 8), which means you can lock those buggers out :cry: and no matter how far they push the mixer the system won't get any louder :twisted: Now the mixer could still produce distortion from the clipped signal, but at least you aren't driving the amps into clipping, which WILL DEFINATLEY kill speakers... :(

    Remember to leave sufficient headroom in your plan for safety sake...

    gadget
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    Gadget wrote:
    Yes, and then you set the 260's brick wall limiter, and LOCK THE SON OF A BITCH :lol: so they CAN"T exceed the point you set in the DR :wink: You see we still need to get all the equipment into the most linear part of their signals, and the gain structure is the only way to optomize that aspect . Note: I'm not proposing you leave them @ that point, I'm suggesting you back the mixer down 6-12 db minimum for headroom. I have as I said, 28 DB over -0- VU, and I seldom see that -0- vu durring even a live show (the system does tripple duty Live, karaoke, and DJ...

    The 260 has multi level password encoding 8), which means you can lock those buggers out :cry: and no matter how far they push the mixer the system won't get any louder :twisted: Now the mixer could still produce distortion from the clipped signal, but at least you aren't driving the amps into clipping, which WILL DEFINATLEY kill speakers... :(

    Remember to leave sufficient headroom in your plan for safety sake...

    gadget


    OK I will set everything (mixer, driverack and amps) to all hit red at the same point and then set the limiter to brick wall peakstop so the amps don't clip.

    My mixer (Rane Mp & XP 2016a) only has 1 red light in the meter and it comes on at +10db so after I set the gain structure I will go ahead and back the mixer gain down to 0db for 10db of headroom.

    I know that the dj's will have it all the way back up in no time though. They usually are solidly spanking that +10 red light so I figure they are probably hitting at least +15db. So that headroom will usually be used up imediatley.


    As I said no matter how much headroom I give they are going to clip the mixer its only a matter of how soon, so what I want to know is this. As long as I have the limiters set so that the amps can't clip, if the dj's are solidly hitting the red on the mixer and driverack, is the sound going to be audibly distorted or will I be ok?
    .
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    GadgetGadget Posts: 4,915
    You know, each piece of equipment is different. The only way you'll know is to duplicate what they do and see what happens. I know I would... the thing is, as you hit the brick wall harder, and harder, that action is going to become more and more audible as a pumping sound. Now if I was a vain DJ (which I am) :lol: I'd certainly not want that happening :oops:.

    Also just remember, even though the mixer is clipping, and sending out +10-15 db/vu , your LOCKED driverack will be gritting its teeth :x and refusing to allow any more of those db's by. :lol:

    The reason those morons smash the gains to the wall is they don't HEAR any distortion... and a straining system isn't necessarily a distorting system... :shock:

    G
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