mm productions

professional sound equipment hire/sales

professional sound equipment hire/sales

Gain Structure - 6 - Setting the gain-4     
Step 4
Now go to your amplifier. Now, it is important to know that the gain controls on the amplifier are really sensitivity settings, i.e. they set the sensitivity of the input circuitry to the signal you input. Put another way, if the sensitivity setting is at maximum or the control is at its highest, you will need a smaller signal to produce the full power output of the amp. Conversely, if it is set to minimum, you will need a very large signal to get full output. As before, what you want to know is what is the setting of the amps sensitivity control that gives maximum output from the amp when you are inputting the largest signal from the mixer.

With this in mind, the procedure is as follows -
  1. Make sure the amps inputs are at zero. You might also like to warn everyone that you are about to make a lot of noise.
  2. Output the maximum signal from your mixer that you are going to use. If the mixer has a noise generator, you could use this, but make sure you use several frequencies, or even better, a pink noise setting. (Pink noise is a sound containing all audible frequencies with equal energy per octave - when testing speakers it corresponds to the energy distributed across frequencies that music provides). Use the mixers LED ladders to set this up.
  3. Position someone in the auditorium to check level in the space.
  4. Slowly increase the input gain on the amplifier, keeping an eye on the amplifiers clipping or peak led. If it starts to light, stop turning. If you wish, you could turn it back a couple of clicks.
If you are using professional level (+4dBm) mixers, you will probably find that the amp gets nowhere near clipping before the sound becomes uncomfortably loud, and the set up is halted by the person in the auditorium. It is common enough to have only turned the input control of the amp a few clicks. Do not worry about this. Again, I repeat, the input control is a sensitivity setting. If it is set to 50%, it does not mean that you are only using 50% of the amps power!
Step 5
Now set up the EQs to your liking on each of the inputs. Remember, particularly if you boost by a significant amount (>3dB), you will need to readjust the input gain to allow for this. You may have to reset the mic if you can't get the sound you want, and this will obviously mean that you will need to reset the input gain.

Step 6
Now do a rough mix of the sounds. What you want to achieve is a mix where the input faders are all roughly at the 0dB position. This gives the best signal-to-noise ratio in the mixer. If you find that any faders are positioned consistently much higher or lower than the 0dB position, then it may be worth adjusting the input gain.
Similarly, you want to have the mixer master output faders at 0dB, and if this is not the case, again, adjusting the channel input gains may be necessary.
 back to top < previous page - - next page >
     
Home Java Find Function Java Site Search Box
    
How to
guides
Gain
Structure
Page 1
Page 2
Page 3
Page 4
Page 5
Page 6
Page 7
Page 8
Page 9
       
mm productions, Unit 10 Smeaton Close, Severalls Industrial Estate, Colchester, Essex CO4 9QY
Tel 01206 845947; Fax 01206 853756