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  #1  
Old 03-03-2013, 07:25 AM
Tigerspill Tigerspill is offline
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Default Managing Signal Level through SC48/System Controller/Amps

Hi,

I know this is a fairly general question rather than Venue specific (but I am using an SC48). So I hope someone can help me.

Our church system when currently at a normal listening sound level, it doesn't allow me to set good input gain levels on the inputs; they sit way too low (maybe 12db too low on the channel level meter). This means when I plug in Protools (FWx), the levels are way too low (PS I think I can increase these on the Direct Output controls but would preferably fix the core problem).

I obviously need to attenuate the output, and this can be done in several places and an wondering where the "best" place to do this in the signal path -

I guess my options are -
1. Pull back the channel faders - I guess this is a bad idea as to get best resolution, I need them around unity.
2. Pull back groups - not great as I dont have everything routed through sub groups.
3. Matrices (I have each area on a different matrix)
4. Pull back the main console output fader.
5. Turn down the amplifiers (all currently set to max).
6. The system controller (Tannoy TDX1). This wouldn't be a full solution as only the main arrays and subs are fed from this.

At the minute I am think of just backing off the amps, but someone told me that they should generally run high.

What is the best thing to do here?

Thanks
TS
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  #2  
Old 03-03-2013, 08:59 AM
Greg C Greg C is offline
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Default Re: Managing Signal Level through SC48/System Controller/Amps

I usually make my system gain adjustments at the processor. In my particular setup the amps are always set wide open to avoid errors. The processor input gain is set so the board is running at the top of green on the main outputs for nominally loud and hitting yellow means things are heating up. Subs are run on an aux send so they're independent of the main mix level. They have their own processing which works in similar fashion.

Do you matrix fed speakers have their own processor?
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  #3  
Old 03-03-2013, 09:57 AM
Tigerspill Tigerspill is offline
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Default Re: Managing Signal Level through SC48/System Controller/Amps

Quote:
Originally Posted by Greg C View Post
I usually make my system gain adjustments at the processor. In my particular setup the amps are always set wide open to avoid errors. The processor input gain is set so the board is running at the top of green on the main outputs for nominally loud and hitting yellow means things are heating up. Subs are run on an aux send so they're independent of the main mix level. They have their own processing which works in similar fashion.

Do you matrix fed speakers have their own processor?
So the Stereo mix is fed into a number of matrices.
Two for LR - these are fed into the processor. The processor has four outputs. Each array has five units and we split top three and bottom two as the "throw" is different. I am not actually sure how the subs are fed - possibly a split from the matrix LR.
Other speakers are for fills and are combined LR and are run off other matrices direct to the amps.

So maybe I should tweak the processor for the main LRs .
So on the fills where there is no processor, maybe I should leave the amps open and pull the matrices faders back.

I really need to check how the subs are fed before I do anything. But I am 100% sure they are not fed by an aux.
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Old 03-04-2013, 04:10 PM
Greg C Greg C is offline
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Default Re: Managing Signal Level through SC48/System Controller/Amps

I suspect the subs would be fed by a L+R sum in the processor. If you turn down the input gain on the processor, that should allow you to get your board output hotter. Since the other zones are fed directly to the amps from matrix outputs, you do have the choice of either turning down the amps directly or by turning down the sources gain on the matrix page on the Venue itself. Each matrix source has a level control that goes from off up to 0dB (unity). You can pad the signal down there and leave your matrix sends at unity. I do this quite a bit when feeding someone's -10dBv consumer level based recorder. The main mix output feed to the 2-Track output will be way too hot for those recorders. So I'll use the Main Mix as a source for a spare matrix and then pad that source down 20dB and route that matrix to the 2-Track outs so the recorder doesn't get hammered. You can do the same thing for your zones.
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Old 03-05-2013, 11:32 AM
Tigerspill Tigerspill is offline
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Default Re: Managing Signal Level through SC48/System Controller/Amps

Thanks Greg.
I appreciate the advice. I will look into this maybe at the weekend if I get a chance.
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Old 04-20-2013, 04:31 AM
Tigerspill Tigerspill is offline
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Default Re: Managing Signal Level through SC48/System Controller/Amps

OK - so I have now got this all set pretty good.

I actually used the gains on the matrix mixers to reduce the output levels and have now got really solid signal levels on the channel metres. And I am getting good levels on PT, which I can tweak with the Direct Out level control on the outputs so this is great.
However I have a couple of questions.

1. Having done this, I feel the actual sound coming from the PA seems "better". I cant explain it but it just seems a more robust sound. Is this my imagination or is this possible?

2. I have the peaks in the channel metres occasionally pushing into the red. I assumes this was bad and was expecting the sound to break down. But the sound seemed to be OK. I then tries a CD and pushed the input gain up until it was filling the meter - red and above. Again I had expected this to turn into "noise", but it was fine. So there seems to be headroom above +15 on the channel metres. Anyone know how much headroom there is above +15 at the top of the channel metre?

Thanks again.
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Old 04-20-2013, 11:23 AM
vikingthor vikingthor is offline
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Default Re: Managing Signal Level through SC48/System Controller/Amps

Quote:
Anyone know how much headroom there is above +15 at the top of the channel metre?
I don't know if you are referring too the option page, there you can set the input clip treshold. So Venue might say a channel is clipping, while there might be 6 db left. You can also choose between RMS and Peak metering. what might have influence on how you set gains and read the meters.
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Old 04-20-2013, 01:07 PM
Greg C Greg C is offline
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Default Re: Managing Signal Level through SC48/System Controller/Amps

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Originally Posted by vikingthor View Post
I don't know if you are referring too the option page, there you can set the input clip treshold. So Venue might say a channel is clipping, while there might be 6 db left. You can also choose between RMS and Peak metering. what might have influence on how you set gains and read the meters.
Yup, -6dB is the factory default for the clip lights to light up which is supposed to give you some "headroom" before actual clip. But I don't like it that way at all. That false clip indication drives me crazy. So I always set that to 0dB (off). What I have found is that even when you hit clip, it's not audible say when a vocalist really screams into the mic unexpectedly and slams the preamp unless you're really clipping hard. It was a pleasant surprise to find that was the case when I first started using the Venue. I don't make a habit out of letting that happen, but it's nice to know you won't get egregious digital clipping when it does on occasion.

I know Midas incorporates a "soft clip" circuit into their mic preamps on their digital consoles per a post by one of their engineers on another forum. This is part of what defines the Midas "sound" apparently. It seems the Venue might be more forgiving than other consoles as well.
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  #9  
Old 04-20-2013, 01:10 PM
Greg C Greg C is offline
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Default Re: Managing Signal Level through SC48/System Controller/Amps

Quote:
Originally Posted by Tigerspill View Post
Having done this, I feel the actual sound coming from the PA seems "better". I cant explain it but it just seems a more robust sound. Is this my imagination or is this possible?

In theory, you're using more bit resolution on your channels and summing buses when you run them hotter. Also with some desks, there's anecdotal evidence that running the analog mic preamps hotter also seems to sound better. The combo of these things might be what you're experiencing.
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  #10  
Old 04-21-2013, 01:35 AM
Tigerspill Tigerspill is offline
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Default Re: Managing Signal Level through SC48/System Controller/Amps

Thanks Guys.

I am using RMS ballistics for metering
My "Input Clip Margin Below Max" & "Output Clip Margin Below Max" are both set to 6dB. Does this mean the Venue indicates clipping 6dB before it actually is clipping. and would I be better using peak monitoring?
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