Signal Processing

At a Glance

When using certain system in the auditorium some signal processing is required if not recommended. The Control booth currently has six components responsible for signal processing, however only five are in regular use.
From top to bottom on this left photo our primary signal processors are

  • DBX 215S Dual 15 Band Graphic Equalizer for the Tier Speaker and Subwoofer

  • DBX AFS2 2 Channel Feedback Suppression Processor for Front of House Left & Right

  • DBX AFS2 2 Channel Feedback Suppression Processor for Center Left & Right

  • Behringer DCX2496 Ultradrive Pro Crossover for the Subwoofer

  • Altec Lansing 1742A Signal Delay Unit for the Tier Speaker

NOTICE: YOU SHOULD NEVER NEED TO MAKE ANY ADJUSTMENTS TO ANY OF THE PROCESSORS DISCUSSED ON THIS PAGE (with a few exceptions).

Powering Up

To power on these processors you must flip the red switch on the Pyle Auxiliary power unit. This will not only switch on the 5 processors units in Rack 2 (Control booth right) but also the Hearing Assistant Transmitter and Intercom System power supply.

Dual Band Equalizer

This dual band equalizer is covered up by a rack unit cover to prevent tampering. Hence the modification its controls will not be discussed and should be left as is.

Channel 1 of the equalizer drives the Tier speaker. Its EQ essentially lifts the low end sound frequencies up a bit to try and emulate the sound that the two Front of house speakers produce.

Channel 2 of the equalizer provides some fine tuning to the Subwoofer before handing the signal off to the Crossover unit via patch panel B.

Both of the channels on this unit can be bypassed on the patch panel, but needed to do this is rare.

Front of House Feedback Suppressor

This feedback suppressor is now a permeant part of the two Front of House speakers as it connected directly in line between patch panel B and the front of house amplifier. In the event where a movie is being played its a good practice to click the "Bypass" buttons on the unit to bypass any processing therefore allowing the full sound spectrum to go to the speakers. There are two presets programed into this feedback processor. Preset 1 is the typical floor system setup and is what the unit will be set to most of the time. To change the unit to another preset or revert back to the default preset (in this case Preset 1) follow the steps listed here.

  1. Push MENU/BACK

  2. Turn the wheel to load preset

  3. Push SELECT

  4. Turn the wheel to the desired preset

  5. Push SELECT

NOTICE: DO NOT CLICK THE WIZARD BUTTON - This should be done only in the cases where the system needs to be modified and this is rare. After all the feedback Processor will continue to hunt through the entire audio spectrum looking for feedback and suppress it as fast as it can. Aside from setting it to bypass mode or reverting back to its default preset user interaction is rare.

Center Left & Right Feedback Suppressor

This feedback suppressor is now a permeant part of the two center speakers as it connected directly in line between patch panel B and the center left & right amplifier. This feedback processor has been configured for use with the theater mics and will occasionally have other presets programmed into it for different shows with different levels. The default preset on this unit is Preset 1. To change the unit to another preset or revert back to the default preset (in this case Preset 1) follow the steps listed here.

  1. Push MENU/BACK

  2. Turn the wheel to load preset

  3. Push SELECT

  4. Turn the wheel to the desired preset

  5. Push SELECT

NOTICE: DO NOT CLICK THE WIZARD BUTTON - This should be done only in the cases where the system needs to be modified and this is rare. After all the feedback Processor will continue to hunt through the entire audio spectrum looking for feedback and suppress it as fast as it can. Aside from setting it to bypass mode or reverting back to its default preset user interaction is rare.

Behringer Crossover

The Behringer Ultra drive Pro crossover is configured to send only the required sound frequencies to the subwoofer. It is connected through patch panel b and goes in between Channel 2 of the EQ unit and the Subwoofer amplifier.

As always DO NOT MAKE ADJUSTMENTS TO THIS PROCESSOR.

The processor is wired so it can be bypassed through patch panel B if needed and is in between Channel 2 of the EQ Unit and Subwoofer amplifier signal flow wise.

Because this unit should never need to be touched I will not go into its menu settings but I will share these two pieces of information.

  1. Its lower and upper frequency should be 125Hz

  2. Its default preset is named 'J8X' should it need to be restored.

Altec Lansing Signal Delay

The signal delay unit is configured to provide 36ms of delay to the tier speaker. This delay comes before the EQ unit for the tier speaker. This unit should never need to be touched ever, hence why I will not go into the details of how to operate the unit. Should it be tampered with the only menu setting that needs to be changes is setting the delay to 36ms. For some reason this unit cuts down on low level sound frequencies going to the teir speaker when in use. A menu setting is used to boost low levels to bring the back to their normal state.
This unit is locked to prevent changes.

This patch panel which updates automatically shows the signal flow between the processors and amplifiers. Notice how for normal signal flow little patching is needed.