Best level to feed the club PA?

Another rookie question... I have about 20 ways to control the dB level I'm pumping out by the time it leaves my setup, and goes into a 2 channel Crown amp at the bar I DJ at via RCAs.

In my chain from start to finish I have the faders in traktor (always keep those around 7 for headroom), the master gain in traktor (keep that slightly above even), then the gain on my Audio Kontrol 1 (that is around 75%), then the fader gain and master fader gain on my external mixer (keep those around even), then a +4db switch on my external mixer (this is on) and then off to their amp.

This is probably gain staging 101 but I just don't know what to do.

Usually an hour or so into a bass heavy set, their amp craps the bed completely (lights turn red, assume it is overheating), and we're left with only the sound I feed to my self powered JBLs, but it sounds awful, and they aren't going to be fixing or buying any new equipment.

My question is, how can I best avoid killing their amp? Should I be feeding less/more volume?

you don't want to run the amp as hard as possible for long amounts of time. 75-80% is probably better. could be that the amp and speakers aren't paired *exactly* and that means that the amp could crap out easier if the ohm load isn't right.

I'd think that if you are feeding their amp a nice clean signal that isn't overloading the initial input gain stage, the problem would be more related to a mismatch as mentioned above, or simply that the amp is turned up too high. Try bringing the volume down a bit and see how that goes. Having a quieter PA overall seems better to me than having only your monitors after an hour.

hey

yeah really sounds like more of a problem with the sound system just being a little too small for the job to me.

No matter what gains you have at your various stages inside tractor and stuff, the amp cant really see this all it sees is whatever the final level is coming to it it doesn't know anything that's happened before that and so as long as your feeding it a nice clean signal that isn't too quiet on one hand or clipping and distorted on the other then it should be ok.

Its really after that inside the amp that will be causing the problem and it sounds like your trying to push too much volume out of too little system.

k

Keep everything as close to unity as possible (meaning line faders all the way up, traktor master output close to 0 but not clipping, audio kontrol at max, mixer pgms peaking around +6, etc) to avoid unnecessary boosting down the line, and try not to push your amp too hard because it won't like that.

agreed, unity is where you want to be...with just about everything, until it comes out of the amp.

I usually soundcheck with my volume faders on my mixer all the way up, the gain on each individual channel barely touching unity. Then from my mixer to the amp where the amp gains are where they would be picking up the most signal i would want them to at the loudest part of the night...then, don't touch anything...and stay the fack away from the gains on your dj mixer, or in traktor(whatever).


if it is an overheating problem, the amp may not be getting enough air. Pull it away from the wall a bit, or if there is room, throw a fan in there.


cheers,
tim

It's pretty simple.

Before the amp
As loud as you can in each stage without clipping. Why? to have a greater noise to signal ratio. Each step in the analog world produces noise. When you amplify a signal you also amplify the noise, because if you have a weak signal it will be closer to the noise. Amplifying a loud signal is not always necessary so you only have to worry about adding noise, not amplifying it.

In digital it's the same but for other reasons. A clipped analog signal can sound good when you're only clipping a few dbs. In digital clipping means you are cutting the waveform and having a flat line instead of a curve. That is really bad.

Plus a clipped signal will have more energy than the non clipped signal, which can blow your speakers, and also tear down your speakers.

After the amp
Never work with an amp to full power. There are many reasons. As others have said overheating is a problem, but also because if you have a peak on your audio path you could blow your speakers. Even if you never have any of those problems working with the amp at full power and speakers wil tear down your system faster in the long run.

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Originally Posted by fastirwin

Another rookie question... I have about 20 ways to control the dB level I'm pumping out by the time it leaves my setup, and goes into a 2 channel Crown amp at the bar I DJ at via RCAs.

In my chain from start to finish I have the faders in traktor (always keep those around 7 for headroom), the master gain in traktor (keep that slightly above even), then the gain on my Audio Kontrol 1 (that is around 75%), then the fader gain and master fader gain on my external mixer (keep those around even), then a +4db switch on my external mixer (this is on) and then off to their amp.

This is probably gain staging 101 but I just don't know what to do.

Usually an hour or so into a bass heavy set, their amp craps the bed completely (lights turn red, assume it is overheating), and we're left with only the sound I feed to my self powered JBLs, but it sounds awful, and they aren't going to be fixing or buying any new equipment.

My question is, how can I best avoid killing their amp? Should I be feeding less/more volume?

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I know Im going against the grain on this, but try this (this of course assumes that the system you are playing can support the volume you need):

Max out the amp(s).

Control the overall volume with the master on the mixer; lower when the room is empty, and louder as the room fills or as needed

Im not sure how the Audio Kontrol 1 identifies 0db, so I suggest you work with it until you find that sweet spot.

Keep the faders at max level (assumming you mix with the crossfader)

Maintain your gain structure with the input pots; the goal being to stay within the 0db range without ging too low or too high. Pipping the red every once in a while, is not a big deal, just try not to keep the levels in the red for too long. Same applies for playing lower than the 0db ideal; playing a track too low also compromises headroom. This is one of the most important parts of the signal chain since this keeps your music sounding crisp and dynamic.

Good luck.