Compression/Volume etc...etc...
premier1
Posts: 119
Ok I have read everywhere NOT to use compression on the whole mix however when I push my system to its max I have to use the limiter function to stop clipping but when I do that it has to come down so low that it really takes alot of gas out of the system, so I decided to add some compression, I set the threshold at -10 and the gain at minus 5 the ratio is 8:1 that seemed to stop the clipping and I was also able to turn up the limiter enough to gain some power back, Is this tweaking of both parameters acceptable to acheve a safe level as to not harm the speakers? To be honest I really dont know the difference between the limiter and the comp?? they really seem to do about the same thing, I definatly get more out of setting the gain than anything else on both..No as far as gain structure, everytime I do it the way I read it seems to take alot of volume away and I am turning down my amp knobs alot ! So I keep starting over and doing it all again and always end up having to mess around with stuff in the end, what the f$%^%%^& am I doing so wrong? also Should I run this thing in st or mono...I am currently do everything in st..Sorry I am such an idiot but there is alot to absorb and I thought by noiw I would have it right, sometimes its ok other times its lost on me. Of note I do have a seprate comp on inserts for my Kick drum and snare other than that everything else is via the DRPA, My board has a one knob comp ( yamaha mg166cx) But it doesnt seem to do much of anything and I dont know if that hurts the drpa using it of what. Thanks Yet again ! :?: :?: Just seems I at least must have a decent small club system here not the best but it should sound ok and pump out enough volume for the venues I play, I either dont get enough or feedback or to many highs...LoL.....
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Comments
G
You said when you push the system to the max -- you have to use a limiter to keep it from clipping. That is what you should do BUT if your system isn't loud enough then you have to ask yourself a few questions:
1. I am really out of gas? You very well could be so don't push it harder -- that won't fix it. This means you need more speakers and amps........ most likely.
2. You could have your gain structure wrong. Most people think the amp needs to be wide open on the front otherwise they won't get full power out of it. That isn't the way it works. If you have a driverack manual look at the last two pages of the book where it talks about gain structure. Most amps will clip with about 6dBu of input signal or more whereas a mixing board takes much much more output signal (18dBu to 24dBu) to achieve that.
So you are sacrificing around 12dB of headroom -- IF you have done the gain structure improperly. At this point, I am not convinced yet that it is set right.
Go back and check that. Use pink noise into a channel on your mixer with EQ's OFF, compressors, gates, limiters OFF. Start with good clean signal. Follow the procedure on the back of the driverack manual EXACTLY.
IF you don't have a DR260 and you have one of the other DR's -- setting the limiter may not help you much since they don't have a brickwall limiter. The 260 does. So when you reach the clip point on the amps -- that is all the gas you are gonna get so don't push the system further otherwise like Gadget said -- the smoke will come out of your speakers. The heat has to go somewhere.
Using limiters are fine if you know how to set them up BUT honestly if your gain structure is correct -- it will tell you when your are at the clip point. Don't go any further.
Compression should be used on an instrument or musician that can't maintain their volume consistency. For example a crazy loud snare drum, a slap happy bass player, a vocalist who doesn't sing very loud but screams really loud......etc. Use it to TAME those instruments. When placed on the whole mix........ makes it sound sterile. There is a very fine line where you can get away with that but it takes a bit of experience. You shouldn't HEAR the compressor working. If you hear it "Breathing" -- then it is set to hard.
Compression is different than a limiter but if you compress with high ratios 14:1 to infinity and crank the threshold -- you have turned the compressor into a limiter.
Hope that helps.
Speaking of clipping, is it ok to see the red light for a split second on the peaks? or do you NEVER want to see even a hint of red flash? Some owners manual's say "just to the point of clipping" and also state that its ok for the light to come on now and then but not continues?? Just asking, Thanks so I know exacly what I am shooting for here
I can tell you where you will go wrong with this so be careful. When you use pink noise into a channel on your mixer you will probably raise the channel gain (or Trim knob) up until you see it clip and then back off of it a tad. Make sure you back off just a tad more than a tad. The reason I say this is -- when you have other channels routed to a sub group like all the vocals or all of the drums -- they are going to SUM together and then your sub group will be really hot. Allow yourself just a bit more room.
Just experiment with this particular part of your gain structure. The rest of it is pretty easy.
Next, set your channel fader at UNITY, then bring the MASTER up until you find the clip point on it ( I hope your speakers are disconnected first). Hopefully, you get to at least unity before you see clip lights. My board clips right around +5 on the meter BUT if every channel strip knob is gained out till barely clipping -- then I am lucky to get the board to unity on the master fader. Does this make sense so far?
Mark the clip point on the mixer and back it down until the master isn't clipping anymore. Now look at the DR meters. What does the INPUT say? If there is NO clipping there -- then there shouldn't be any clipping on the output meters either.
Move onto your poweramps & raise the knobs on the front up slowly. If you get them wide open before they clip -- then leave them there BUT if they clip before wide open -- you have to back them down until the red lights go off.
Now go back to your mixer and see if you are on track. Does each device reach it's clip point together? If so, you are pretty much done.
One more thing -- just because you have maximized your gain structure you still have to be careful that your speakers can take the power. They don't have little red lights on them telling you when they are clipping.
Find the rated RMS value or program value on the speaker and you will have to make sure your amp is powerful enough to deliver what it needs.
My tops are rated 600watt RMS, 1200watts program, 2400watts peak. DBX says I need 1.5 to 2 times the rated RMS value to be safe so that means a 2400 watt amp in bridge mode to deliver 1200 watts to each speaker at a 4 ohm load.
We set the gain structure to maximize your signal for the best signal to noise ratio. And you know when your mixer clips -- your amps are at their clip point as well BUT this doesn't necessarily mean your speakers can handle it. It just means you are at least not sending a clipped signal (square wave) to the speaker which is really bad.
Ok man, give it a shot.
Dr. J
I always have a reason for my posts...It may be that I'm trying to get you to think... It might be that I want you to review what we have already covered, or some of the reading I have suggested... it could be that you have missed something that I said earlier....perhaps I didn't have time for a full on explanation at that moment and that I was going to re-visit the topic when I had more time...
We answer hundreds of questions a month, and it gets a little tedious when we post an answer, and then there isn't a reply for days or even weeks at a time...this goes to the interest of the subject, and the answers to our questions...when a subject gets posted there are lots of lurkers... they are learning form these posts as well even though they don't post, so these things also need to be taken into consideration as well...
Also we answer some questions A LOT! and that is the reason for the FAQ section and the READ ME FIRST BEFORE POSTING on the top of the opening page...
Now, the reason I posted that, was that I wanted you to think...and I wanted you to ASK the question...you did not...I wanted you to know that that is a very dangerous thing.. stacking limiting and compression. There is much supposition about limiting and protection but here are the facts...
1. Expecting the limiters (even brick wall limiters) to protect your speakers is a BAD IDEA!
2. Limiters are for unforeseen event protection (a dropped mic or that type thing)
3. Gain structure and KNOWING when your system is near clipping (and avoiding this by turning the system down) is the ONLY real way to insure you are not going to smoke your speakers
4. if you aren't getting loud enough and the system is near clipping... YOU NEED MORE SYSTEM!!!!
The thing is, and the reason for the warning, when you depend on a limiter/compressor to get the system louder, the duty cycle of the amplifier goes up... instead of running @ 1/5th power output your amp duty cycle starts to climb...the higher the duty cycle the more exhaustion there is in the amps power supply , and when it's gone... even though the clip lights aren't even ON, the amp is heating the voice coils, and the smoke is ready to reveal itself...
Do the gain structure... set the limiters up the way you want them, with the threshold set to max, get the system at the volume you want to run, lower the threshold till the gain reduction starts to flicker... when the gain reduction starts to WORK.. TURN THE SYSTEM DOWN!!!!
A occasional flicker of the clip light is not a death-nil...for the speakers... constant red WILL let the smoke out..
BTW it was 3 days after I posted the "smoke warning before I asked if you were not interested in WHY...
G
G
I have my Lows set at 60 and 100 bw 24 gain +5 I have my tops set at 125 lr 24 gain set at 0.0 are you saying bring the top down to 100 so its on top of the low 100? Thanks!
Lows:
HPF 55hz BW18
LPF 100ha LR24
tops:
100hz LR24
Now, if you have the gain structure set up properly, and you know where and when the amps are WILL clip (as in the mixer should clip BEFORE the amps)
As for limiting... if the gain structure is proprerly set...and you know where the mixer will clip, try and maintain 6-12 dB of headroom... so with that in mind, IF you want to set the limiter use Jerry's setup instructions...
BTW.. were here to help.. have been (myself) for more years than I can remember...We do expect that the poster learns something here.. were not big on just giving all the answers... it all goes back to that age old proverb... give a man a fish and he will eat for a day, teach him to fish..and he will eat for a lifetime!
Gary
Oh and this sound guy better give me some click in my kick drum! have to have that click! nice and tight! lol....
But in all, sounds like you are getting a handle on things.
DRA
G
sorry dude..
G
Now if I had 8 FANES -- I am certain they would do very well against the JBL's & EAW's -- probably take them. I just don't see the sense in spending a minimum of $1,000 for a single 18 store bought box when I can have two custom Fanes.
Everywhere I go around here people ask about the subs -- like what brand are they? When I tell them I built them -- they are floored!
The next subs I get will be Labsubs.
http://www.fane-acoustics.com/resources.aspx