Amp volume setting clarification

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djoutlaw

New DJ
Jun 17, 2008
225
0
I would like some clarification on how you all set your amp volume level and why.

I have been told two different ways to set the amp volume and would like to know which one is the right way or if it is a personal choice.

Lets assume that the amp is correctly rated for the speakers.* One way that I have been told is to turn your amp volume all the way up but watch the master volume level on the mixer (keep it around 3/4, but don't max out).* The other way I was told is to turn your amp level to only 1/2 to 3/4 but you can turn the master volume level on the mixer to max.

What is the correct way?
Is it a personal choice?
Is one way more damaging to amp & speakers?
 
I can't say if it's a personal thing or not. Like Cam, I've always run my amps at full gain for maximum headroom. I adjust the overall total gain and output to the speakers with the Master Gain on the mixer. If I need to tweak here and there, I do that with the compressor/limiter unit and the EQ knobs on each channel of the mixer. If I need to get really aggressive with the gain structure, I use the ratio and threshold controls on the compressor.

Hope this helps.
 
This is a subject that I have gone back and forth over with others I respect. Some say 'run it wide open' while others have a more complicated approach involving setting 'unity gain'. That way works best for me, personally. I set everything in my signal path to unity '0'. Then during sound check, I turn the amps to the highest setting I think I will need for the night and no more. I then control my volume with my master fader. I am convinced this is why I can walk right in front of my speakers with a live mic and hardly ever get any feedback. When I tried to run my amps wide open (even at lower overall volumes), my mics would become super-sensitive to feedback. I would think that active speakers would be even more sensitive if run wide open.
 
It seems to me that if you are running an amp which is (at a minimum) 1.5 to 2 times the rated power of your speakers and you run your amps wide open, that you could potentially blow your speakers with one accidental bump of your master volume fader. I know a compressor could help with that, but it ain't fool-proof. Why ask your amp to run wide open when it's power you will never need or use. Let the amp cruise all night.

I've asked this question before, but if amps were meant to be run wide open, then why do thay have volume controls at all?
 
DJ Wes said:
It seems to me that if you are running an amp which is (at a minimum) 1.5 to 2 times the rated power of your speakers and you run your amps wide open, that you could potentially blow your speakers with one accidental bump of your master volume fader. I know a compressor could help with that, but it ain't fool-proof. Why ask your amp to run wide open when it's power you will never need or use. Let the amp cruise all night.

I've asked this question before, but if amps were meant to be run wide open, then why do thay have volume controls at all?
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Good point!
 
DJ Wes said:
Next obvious question is: Do those who run 'wide-open' have any mic feedback problems?
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I did have feedback problems when I was using a cheap mic. But now I have a Audux OM-5 and a dbx DriveRack 260. The DriveRack has AFS fixed/live filters that fight back. So now I have no feedback problems:sqbiggrin:

As far as amp settings go I have my QSC 153i set to 12 o' clock. Then for my passive subs I run a bridged amp wide open.
 
One last thought. For those who run wide open, when you pause your music can you hear a hissing sound coming from your speakers? If yes, that's because the signal to noise ratio is bad. That hissing doesn't go away when you hit 'play'. It's still there, just covered up with the music. When I pause my system you have to physically put your ear right up next to the speaker to hear any hiss. Good clean signal path is what I'm striving for.
 
DJ Wes said:
One last thought. For those who run wide open, when you pause your music can you hear a hissing sound coming from your speakers?
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I do not get that, either. Maybe my Peavey equipment and/or my Gemini mixer are good, after all!
 
From what I've read and my understanding is the following. When you run your amp and you have the clip lights just flickering your output is no where near full output according to my QSC manuals you are at 1/8 output, when heavy clipping occurs you are at 1/3 power output and full power with 1% THD and constant clip. In my RMX 2450's power draw is listed as follows:
1/8 power 1/3 Power Full Power
Idle 0.6 AMPS
8 Ohms 4 AMPS 9.7 AMPS 16.4 AMPS
4 Ohms 6.3 AMPS 15.6 AMPS 27 AMPS
2 Ohms 9.2 AMPS 23 AMPS 41 AMPS

With this you can say that you would need a very sturdy electrical installation and outlets that can handle such a power draw. What you're looking for is enough headroom to actually get the correct amount of power to the speaker to get it's full potential. We know that an amp rated at 200 watts RMS of output is not going to feed a constant 200 watts to the speaker it will fluctuate in numbers a lot lower than that.

This is the reason we see many videos on the net of people trying to melt speakers with big amps and they take an eternity in some cases to do some real damage.

I have fed my Cerwin Vega AB-36B's with a pair of bridged RMX 2450's and they sound great with the clip lights barely flickering, I have now fed them with a bigger amp in the same way and the sound difference is enormous. As long as you monitor your levels responsibly you can use a lot of power to actually meet what your speaker demands and have fun.

This is another reason why the JBL SRX series are so power hyngry as well as some Peavey speakers a lot of the amps people use to power them don't have the correct amount of power getting to them. Once people feed them the correct amount there's a night and day difference.

I run my amps wide open and control the volume with my mixer. I also have limiters set to kick in when there's hard clipping, not when the light's flicker. The peak power the speakers can take let's you do this and before they are exposed to too much power that's when the limiter will kick in.

If you're getting hiss or hum you may have setup the levels incorrectly or you can have a problem with one of the cables in the chain.

Maybe I'm wrong but this is what I understand from what I've read, asked and used ;)
 
DJ Wes said:
One last thought. For those who run wide open, when you pause your music can you hear a hissing sound coming from your speakers? If yes, that's because the signal to noise ratio is bad. That hissing doesn't go away when you hit 'play'. It's still there, just covered up with the music. When I pause my system you have to physically put your ear right up next to the speaker to hear any hiss. Good clean signal path is what I'm striving for.
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I really don't use the mic that much and I don't pay much attention to hiss--maybe I don't have any.* Your point is well taken; next time I DJ I will spend a little more time setting up and checking to see if I have feedback or hiss.
 
DJ Wes said:
One last thought. For those who run wide open, when you pause your music can you hear a hissing sound coming from your speakers? If yes, that's because the signal to noise ratio is bad. That hissing doesn't go away when you hit 'play'. It's still there, just covered up with the music. When I pause my system you have to physically put your ear right up next to the speaker to hear any hiss. Good clean signal path is what I'm striving for.
Click to expand...

I used to use the EON G2 they had a hiss coming from them all the time. My QSC 153i are very quiet. My Peavey CS 3000 amp is used to push my subs and it's quiet too.
 
Something to bear in mind about gain structure ~ amp attenuation is not really a part of gain structure. Everything before the amps is gain structure.

Remember, these are attenuators, not volume controls. A volume control limits what's fed to the amp. Attenuators control what the amp is allowed to put out. There's a difference. :)

We run all of our amps at no attenuation (full). The reason for this is to maximize our amp headroom. We've not had an issue with feedback nor floor noise because we run all balanced line components from front end to amps. All mics are XLR. Sometimes a ground lift is needed, sometimes not. But our system is very quiet for the power it can dissipate.

If you have a compressor/limiter in the processing chain you won't have to worry about too much amp headroom doing damage.
 
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