Powered speaker volume

[RoadRanger]

Opinions about this http://www.rane.com/ranegain.html

Looks like a great product for the stereotypical DJ .

[agedhorse]

Knowing the clipping/limiting level is an inexact number... and in fact can be a set of numbers. The last DSP limiter section I measured had about 4dB of hysteresis between the attack and release thresholds, meaning that you better have adequate headroom to accomodate any possible unknowns that may alter the gain structure along the way.

 

For example, you may have everything set to clip at the "same" point but then you adjust the eq adding 3dB at 200Hz. Now, 200Hz will clip earlier by 3dB relative to the broad band metering and you may have problems.

[Jersey Jack]

Hmm....I'm glad that my question has garnered so many responses, but I'm finding myself more confused. I in fact do have RCF 310a's, and it is precisely the volume control (infinity on one end, MAX on the other) that causes me concern, because there is no detent or other marking for 0dB. (I also have a few JBL EONs that I use as monitors, and they have the marking, so I'm cool there.)

 

A bit more about my situation: This PA is used only for my band--a low-key amateur outfit with no soundman; we run sound from the "stage," and we're unable to go in early and do sound checks. (There are always people already there when we load in.)

 

I understand gain-staging, but it would be helpful to have a starting point. Should I then keep the volume on my RCFs directly in the middle of infinity and MAX?

[dboomer]

 

I understand gain-staging, but it would be helpful to have a starting point. Should I then keep the volume on my RCFs directly in the middle of infinity and MAX?

 

 

Then you don't understand gain staging ... because the middle doesn't mean anything. The starting point is all the way off.

 

Now with your mixer theoretically at max (wherever you define that point relative to my last post) turn the speaker/amp sensitivity up until you either have enough level for the max you will need for the gig or until the limiter LEDs just begin to fire. That's the point you are looking for ... regardless of where it is in the travel of the knob.

 

Per Andy's post ... if you then boost 200 hz by 3 dB you weren't at max to begin with.

[Mutha Goose]

 

...For example, you may have everything set to clip at the "same" point but then you adjust the eq adding 3dB at 200Hz. Now, 200Hz will clip earlier by 3dB relative to the broad band metering and you may have problems.

 

 

You can never be fool proof. If someone wants to bad enough, they can and will f' things up. In the end, if you want to try to minimize your chances for error, you have to start from some "known". If you know where you are and what the limits are and care enough to heed both, you have the best possible chance for success.

[Louis Schwartz]

 

..... The starting point is all the way off. Now with your mixer theoretically at max (wherever you define that point relative to my last post) turn the speaker/amp sensitivity up until you either have enough level for the max you will need for the gig or until the limiter LEDs just begin to fire. That's the point you are looking for ... regardless of where it is in the travel of the knob.

 

 

OK, so just to put this in practical terms for myself, imagining a solo guitar/vocals gig (and hoping that this will be hepful to Jersey Jack, when translated into a full band setting):

 

I'm on stage. I've got everything plugged in. The connections, cables, mics and pickups are all working. I set the gains for my vocal mic and my guitar using the channel trims on my mixer, with the EQs all flat and the channel, master, and speaker volume faders all the way down. Then, since I can't hear the mix in the room, I just set the channel faders to the nominal setting for now. Then I do the same with the master fader. Then, since there's no marked nominal setting on my powered speaker (the RCF 312a), I turn up the volume on the speaker a bit and play and sing. Not loud enough, so I turn it up some more and pla again. I keep doing this until it's either clearly louder than I'm likely to need it (even later when the room is crowded) or until I see the clip light go on. I leave it like that or back it off slightly if it's clipping. Then, with the help of a friend out in the room I get the overall volume right for the room by backing down on the board's master volume, and work on getting the mix right on the channel faders and EQs. Then I'm good to go. I've got no clipping on my inputs, a good mix, a good starting volume, and some room to turn up if I need to later. I'm not going to clip the power amp in the speaker unless I turn the master volume on the mixer above the nominal setting (and if it was just loud and not clipping at the nominal setting, I'd have even more room to go, keeping one eyeball on the clip light on the back of the speaker to warn me that I've reached my limit).

 

The other option--if I'm understanding all of this correctly--would be to do as I say above, but to set the master volume of the mixer at maximum, rather than nominal, before setting the sensitivity of the powered speaker's input. This way, after I back down the volume on the master fader to get my actual starting volume for the gig, I would know exactly where my maximum setting will be (it will be the maximum setting on the volume control I'm actually using). This will also give me a better signal to noise ratio, yes? I assume that the only variable here in terms of clipping might be that after I've set my maximum at a point below clipping for the speaker, a significant boost in one or two bands of EQ on a given channel during the mixing might mean that I see the clip light go on on the the speaker when and if I do end up turning the master volume on the board all the way to maximum later in the gig (that is, if the boost is big enough) and I should be aware of this possibility.

 

So the second senario has the advantage of being both better for the s/n ratio, still allows me to control volume from the mixer, and it makes it easier to be safe about clipping, but either way should work.

 

Starting with the volume on the 312a at "Max," however, and setting the volume with the mixer's master is a bad idea for a number of reasons, the most important being that with the speaker set at such a radical input sensitivity, I'd have very little ability to control my volume at the mixer. Every little tweak would have too much effect, and I'd probably not be able to get the master volume up very high at all. I'd be squeezed into a very tight adjustment range on my volume control.

 

Does that make sense?

 

Louis

[agedhorse]

Nope, doesn't make sense.

 

You should have ~12dB of headroom at your input stage (before input clip) and you can run your master fader and channel faders down -6 from "nominal 0" and run your speakers anywhere from 0 (max) to -6 and you will end up being right in the middle of the gain structure window.

 

On one side ofthe window is excessive noise, the other side is clipping of something in the signal chain. Ideally you are somewhere in the middle which allows latitude.

[Louis Schwartz]

 

Nope, doesn't make sense. You should have ~12dB of headroom at your input stage (before input clip) and you can run your master fader and channel faders down -6 from "nominal 0" and run your speakers anywhere from 0 (max) to -6 and you will end up being right in the middle of the gain structure window. On one side ofthe window is excessive noise, the other side is clipping of something in the signal chain. Ideally you are somewhere in the middle which allows latitude.

 

 

 

 

OK, so where (in layman's terms) would I change what I described doing to achieve that with my set up?

 

Louis

[rodclement]

OK...so this may or not make sense but it is how I do it...

 

I get our mix on a headphone first so I know everything sounds good and balanced, and I can do it from stage independent of hearing the speakers, once I am comfortable with the mix I check the clipping on the board, once I see clipping I back it out a bit, main speakers are still silent

 

With speakers silent, I add volume to monitors so we can both make sure we are good with their volumes, now with the monitors volume on at gig level, I connect the ipod and play some music similar to ours and with the board volume at our gig level max I bring speaker volume up to the level I want the audience to hear us, I go over comfort level a little bit so I make sure there is no clipping, now I can back up the board volume down a bit to have some headroom without having to touch the speakers and while being sure that the audience will not go crazy...hope any of this makes sense...

 

Rod

[agedhorse]

 

OK, so where (in layman's terms) would I change what I described doing to achieve that with my set up? Louis

 

 

Easy way...

 

Set your powered speakers at -6dB from nominal 0 (or -6dB down from max in the case of the RCF)

 

Set your main fader to -6dB below nominal 0

 

Set your channel fader (saythe vocal channel which you are starting with) to -6dB from nominal 0

 

Adjust your channel trim to where the volume is a good comfortable level. Check your PFL meter, you should be roughly -10dB on peaks below input clipping.

 

Now, to get to gig level if you need more volume, add a db or so to each of the faders and the powered speaker until your vocal mic's at good gig level.

 

Your basic gain structure should be pretty darn close, and the fader positions workable.

 

Easy and takes 30 seconds.

[dboomer]

 

You can never be fool proof.

 

 

Correct. So what you do is leave some that you plan to never/rarely use. This is what's called "headroom". It could equally be called "safety margin". How much you leave is a decision you have to make based on your comfort and skill level and your understanding of what is and might happen.

 

Remember ... headroom is wasted potential. That's not necessarily a bad thing.

 

So a mixer has a point at which you cannot increase the output any further ... "hard clipping". You don't really want to ever use this point, but it IS the upper limit.

[dboomer]

 

Your basic gain structure should be pretty darn close, and the fader positions workable.

 

 

This would be a good goal to set.

[Louis Schwartz]

 

Easy way... Set your powered speakers at -6dB from nominal 0 (or -6dB down from max in the case of the RCF) Set your main fader to -6dB below nominal 0 Set your channel fader (saythe vocal channel which you are starting with) to -6dB from nominal 0 Adjust your channel trim to where the volume is a good comfortable level. Check your PFL meter, you should be roughly -10dB on peaks below input clipping. Now, to get to gig level if you need more volume, add a db or so to each of the faders and the powered speaker until your vocal mic's at good gig level. Your basic gain structure should be pretty darn close, and the fader positions workable. Easy and takes 30 seconds.

 

 

Thank you. This is very, very helpful! One question: I can find "-6dB below nominal" on the master and channel controls of my mixer because they're marked (at least roughly), but there are no marks on the RCF volume, just clicks on the knob. Any reasonable guess as to what would be "-6dB below 'Max'?"

 

Louis

[twostone]

This might help a little and disregard the clipping you definitely don't wanna do that with active speakers. [video=youtube;1hwT15SSwgU]

[abzurd]

 

Thank you. This is very, very helpful! One question: I can find "-6dB below nominal" on the master and channel controls of my mixer because they're marked (at least roughly), but there are no marks on the RCF volume, just clicks on the knob. Any reasonable guess as to what would be "-6dB below 'Max'?" Louis

 

 

 

Just start about 2 O clock (2/3 of the way up). At the end of the process, if you need more, then turn it up. If you need less, or are clipping, then back it down some.

[RoadRanger]

I've never found the master on any of my mixers hard to control if set well below "0" - I've run as low as -25 no prob. I usually pull the master down 5-10db for the break music rather than mute everything and no prob down there either. Nor have I ever had noise issues running the amps or powered cabs WFO - but then again I only have a 9.9KW system so yous guys running "big power" have different things going on I guess. Any excess noise in my systems has always been on the inputs where any proper changes to gain structure wouldn't have any effect anyways...

[abzurd]

I must be doing something right. I can't ever tell if my speakers are on at idle. I suppose if you have "better gear" that's more than enough for the gig, perfectly optimized gain staging isn't as critical as theirs already a low noise floor and headroom all over the place.

 

I did recently start doing my sound checks the "Dave Rat" way where I set the channel strip faders where I want them and adjust the trim from there. And sure, I'll check the inputs to make sure they don't look goofy.

[agedhorse]

Master at -25dB means that with most amps you will be unable to drive the amp to rated output without clipping the pre-master drive electronics inside the mixer. It may work for low levels, but not if you need to get anywhere near the rated output of the amps.

 

RR, your smart ass condecending comment about the rest of us shows that all you care about is stirring the pot and proving the world wrong. Actually, you are showing those of us here who know what's going on inside consoles and gain structure how little you know and how much yo are here only for the agrument. It gets old and is not helpful to those who are here to learn. In fact many of your "drive the snot out of my Behringers", or "try to blow them up" comments are not only unhelpful, they get in the way of the discussions. (IMO)

[RoadRanger]

Master at -25dB means that with most amps you will be unable to drive the amp to rated output without clipping the pre-master drive electronics inside the mixer. It may work for low levels, but not if you need to get anywhere near the rated output of the amps.

Should be obvious that if I want it louder I turn up the master, no? You do it different maybe? I often work private events that want folks to be able to talk to each other without shouting - hence the low master setting. Towards the end I might be up around -10db or 0 even. Outdoors I could be at 0 for the whole event, "it depends" .

 

And I fail to see why my successful limit testing of 'ringer gear bothers you so much? I know there are folks that appreciate knowing that they don't blow up the first time you tickle their limiters like some of yous guys imply. I get a surprising number of PM's and emails from folks afraid to be roasted by asking about low priced gear on this forum .

[agedhorse]

I suppose somebody has to support buying crap and feeling good about it.

[Louis Schwartz]

 

Just start about 2 O clock (2/3 of the way up). At the end of the process, if you need more, then turn it up. If you need less, or are clipping, then back it down some.

 

 

This is interesting. I haven't had a chance to set up and try setting the gain structure the way Agedhorse has suggested (I'll try in my band context tomorrow night at rehearsal, and I'll have a chance with my solo configuration this weekend both practicing at at a gig), but now that I think through the description of the ideal result, I realize that it is more or less what I ended up with at our gig last Friday, with at least one important exception. This was a gig at an art gallery where the space we had for setting up and its relation to the rest of the room made using our full PA both logistically impractical and overkill in terms of volume. We tried that once and it was a mess, but the place is also too big for playing without a reasonable amount of amplification. Last time we played there, we used individual amps for acoustic guitar and lead vocal (a Genz Benz Pro LT), electric guitar (a small Fender amp), and upright bass (a cab and head rig), with 3 background vocals going through an old Peavy keyboard amp and no amplification for our accordion, clarinet, or hand percussionists. The accordion and clarinet got swamped, and the Peavey was less than ideal for the vocals, so this time I set up mics for the accordion and the clarinet and ran them, along with the background vocals, through my new ZED10FX into the RCF 312a, leaving only the hand percussionists unmic'd.

 

I ended up, as I described earlier, with the RCF at 2/3 toward MAX, because that was the loudest I could get before feedback (a good deal louder than we needed). Then, to get the right level, I turned the master volume on the mixer down from nominal, which is where I had started, to what I now see was just about -6dB. Assuming that 2/3 of the way toward MAX is indeed about -6dB on the RCF, as Abzurd has suggested, this is exactly what Agedhorse suggested as an ideal starting point for both settings.

 

The channel volumes were, however, all at about nominal because that's where I set them after setting the input trims just below clipping (I set the imput trims before anything else, using the PFL button and the ZED's meter, with the channel vols and the master vol all turned down and the speaker off). The only tweaking I did later to the channel volume settings was to turn the volume on the accordion channel up a little.

 

I assume, however, from Agedhorse's instructions, that a better practice would have been to set those channel volumes at -6dB to start with. I would then no doubt have found, as I set the channel trims by ear with an eye to the PFL meter, that I was hitting input clip before getting quite the volume I needed. At that point, the thing to do would have been to leave the input trims a few dBs below clip and, instead of turning the channel volumes up to nominal or higher to get more volume, I would have turned the channel, master and speaker volumes all up together just a notch and listened again, then kept doing that a notch at a time until I reached the desired level. At that point, I should have still been below nominal on the channel volumes and have had plenty of leeway to get a good balance for my mix by, for example, boosting the accordion or what-have-you and for whatever EQ adjustments I wanted to make without the danger of pushing the amp in the RCF into clipping. If the power amp on the speaker did clip before I got enough volume that would have simply a sign that I need a bigger set up for the gig. But since I hadn't made that sort of error, once the mix was set I should still have had enough headroom to work with, and I should be able to use the master volume on the mixer to bring the whole thing up a bit if things got more crowded and noisy later in the gig.

 

So, am I starting to make sense now? Sorry to sound like a student, but in relation to you guys that's what I am!

 

I can't tell you how much I appreciate the feedback and information!

 

Louis

[RoadRanger]

to get more volume, I would have turned the channel, master and speaker volumes all up together just a notch

I'm a lazy bastard and that sounds like a whole lot of bother - I'll stick with my "one fader to rule them all" method thank-you-very-much .

[agedhorse]

Gain stages work together as a system, that's why they are there, for those who UNDESTAND how it works. That's why I explain it as I do. Familiarizing yourself with a gain stage diagram (look at some of Yamaha's bigger mixer products) can be enlightening. One fader is like driving a truck in one gear, poor use of tools but for folks who don't understand, I can understand the attraction.

 

Input trim should end up being about 6-12dB below input clipping, and there's plenty of gain throughout to get this when operating at lower levels the way I describe without any risk of loss of headroom problems. Are you sure, Louis, that you are reading your input metering correctly? Different manufacturers and models use different scales.

[RoadRanger]

Yous guys "shifting":

 

w-ffkS37miQ

 

Me puttin' it in "drive":

 

ZHp8Tnz4HfI

 

[Jersey Jack]

The way I understand gain staging is that you want to have each successive link in the signal chain as high as possible (without clipping) to mask the background noise that builds up through successive gain points. This makes sense to me, and it's easy enough to manage this process through metering.

 

But what always confuses me is where one controls volume. I always thought that this would be the mixer faders--channel and master. But with yet another volume control beyond the mixer faders--especially as it is labeled on the RCFs--this model gets confusing. Don't we want to use the final control as a volume control? If not, if the speaker control is after the volume control, how do we set it? In the context of the full system it functions neither as a gain setting nor a volume setting.

 

By the way, I pretend to no special knowledge in live sound, so please do correct me if anything I say is wrong.