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Help a newbie connect limiter/compressor
Old 17th February 2020
  #1
Here for the gear
 

Help a newbie connect limiter/compressor

Hello,

I am helping out (volunteering) with the live sound for a grammar school play where a ~dozen kids are wearing wireless mics on stage. Each mic is run into its own channel on the auditorium house board (Allen-Heath GL2400). Last year we were constantly riding the faders during the performance for fear of loud voices/shouting passages overloading the system (i.e. feedback bang) due to too much gain. (Most of the kids speak softly during the sound check and then overcompensate during the performance...)

Can someone kindly explain how I might connect a single analog compressor/limiter unit (i.e. dbx 166 or another device) so the gain/fader levels can be set once for each performer's channel such that no feedback loop would ever occur during the performance?

Thanks in advance.
Old 17th February 2020
  #2
Lives for gear
 

Quote:
Originally Posted by MusikMan74 View Post
Hello,

I am helping out (volunteering) with the live sound for a grammar school play where a ~dozen kids are wearing wireless mics on stage. Each mic is run into its own channel on the auditorium house board (Allen-Heath GL2400). Last year we were constantly riding the faders during the performance for fear of loud voices/shouting passages overloading the system (i.e. feedback bang) due to too much gain. (Most of the kids speak softly during the sound check and then overcompensate during the performance...)

Can someone kindly explain how I might connect a single analog compressor/limiter unit (i.e. dbx 166 or another device) so the gain/fader levels can be set once for each performer's channel such that no feedback loop would ever occur during the performance?

Thanks in advance.
Hi friend. First off a compressor isn't going to eliminate or make feedback any better. A gate/expander might help with SOME feedback issues on a few occasions but that's not really it's purpose either.

You have a few issues it seems.

1. Kids speaking softly/too loud
2. Super loud speaking
3. feedback

Did you have feedback where the mics would ring out in typical feedback fashion?

A limiter will help squash super loud parts and keep people from being blown away. You can set a limiter to handle super loud parts while still having normal speech dynamics the rest of the time. If you have feedback then this is on option.

If you have a stable system, meaning no feedback, then you can use a compressor to raise the quiet parts and lower the loud parts, but if you have feedback issues then using a compressor this way will make it worse.

How to add a comp/lim depends on how the board/pa is set up. You can send the mics to a sub group and use a sub group insert to hook the compressor up. Get a "insert cable".

Even with a limiter you will still need ride the faders, there is no "set and forget it" without adding a lot of gear such as gain sharing/auto mixing.

I suggest you write down who has the most/main speaking parts, who are background, and set up the mixer accordingly.

To set limiter on a subgroup.

GO to each channel and by fader select on the group button, say 1-2.
Go to subgroup and select "send to L/R"
Insert comp/lim in "group Insert"
Old 17th February 2020
  #3
Gear Head
 

Definitely some helpful information in the comment above... please read that first. But I don't think he quite answered your question... so let me try to help.

First, you will need to determine if you want to put the compressor on a single mic, or 10 compressors for 10 mics, or one compressor on your main out to cover all the mics.

I'm assuming you're planning on the 3rd option. And while this isn't generally how you'd see a professional use a compressor, I can certainly see why'd you'd like to try it. And that's how we learn, by trying things.

So, first you need an insert cable like this - https://www.sweetwater.com/store/det...gaAgcKEALw_wcB


It's important that it be just like this. If you look at the picture, you see a single connector with 2 black rings. And then you see two more connectors with only a single black ring on each of them. This is called a 1/4in TRS to Dual 1/4in TS cable. And, you can see the Dual TS connectors are labeled "tip" and "ring".

I believe your compressor is a dual channel compressor, right?

So on channel 1 of your compressor, take your insert cable and plug the TIP into the IN of your compressor. Plug the RING into the OUT. Then, on the back of your console in the mid section you should see a row of connections called "insert 1, 2, 3 ,4, etc...". Find the"Main L Insert" and plug the TRS connection into it. You now have the compressor "inserted" into you main left channel. Now repeat the process with the second channel of your compressor and the "Main R" channel of your console.
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