Echo Effect (multiple delay lines)

[Craig Maier]

-E

Echo Effect


The Echo Effect is a digital simulation of the old-fashioned magnetic tape delay lines (sometimes called “Tape Delay Echo Chambers”) that were popular in the early 1950s and throughout the 1960s. These devices worked on either of the following basic principles. One method varied the distance between the recording and the playback head producing a variable time delay, a portion of which could be fed back to the system’s input. A second method used a variable speed motor driving the tape media with the recording and playback head positions being fixed, producing similar overall results. The Echo Effect contains two independent delay lines, which can be used in a number of different modes providing it with a great deal of flexibility compared to the old analog systems. Because it performs its function utilizing digital techniques, it does not suffer from the noise and distortion buildup associated with the older analog systems. However, if the so-called “retro” sounding echo chamber is desired, you can use the Echo Effect in conjunction with the Virtual Valve amplifier in the Multi-Filter. The Echo Effect is useful in any of the following applications:

• [*=1]Adding special effects to speech or music. [*=1]Creating certain acoustical simulations. [*=1]Enhancing the articulation sounds on Forensics Audio Wave Files. [*=1]Simulating Stereo from Monophonic sources. [*=1]Creation of “Comb” Filters. [*=1]Adding a simple time delay to one channel of a file. [*=1]Double-Tracking a Vocal to give it more depth.

DCArt10's Echo Effect
The Echo Effect has the following controls:

1. Delay 1: Range: 0.0001 to 5.0000 Seconds (10 uSec to 5 Seconds)
2. Level 1: This control varies the level of the effect produced by Delay 1.
3. Delay 2: Range: 0.0001 to 5.0000 Seconds (10 uSec to 5 Seconds)
4. Level 2: This control varies the level of the effect produced by Delay 2.
5. Feedback: (0.00 to 1.00) This controls the amount of signal fed from the Delay Line outputs back to its input. When this control is set to zero, you will only hear a single delay associated with each of the two delay lines. The higher that this control is set, the greater will be the reverberation sound due to feedback.
6. Output Mix: Range 0 to 100 (0 = Source Only Signal {Dry}) & (100 = Echo Only signal {Wet}). Output Mix controls the ratio of the Source signal with the processed signal. A good nominal starting point for this control is 50.
7. Mode (Modes of Operation Selection Box)

• [*=1]Discrete Stereo: (Delay 1, Level 1 = Left Channel & Delay 2 Effect & Level 2 = Right Channel Effect) [*=1]Discrete Stereo Reverse: (Delay 1, Level 1 = Right Channel & Delay 2 Effect & Level 2 = Left Channel Effect) [*=1]Summed Mono – Stereo Out (Output): This mode is the same as Discrete Stereo except the input signal is summed to Monophonic before being applied to the Delay Lines. The “Dry” signal remains Stereophonic in this mode. [*=1]Summed Mono – Mono Out (Output): In this mode, the input signal is summed to Mono and then fed to Delay 1 Level 1. From there the signal is fed to Delay 2 Level 2 before being fed to the Output. In other words, the two delay lines are cascaded. The “Dry” signal remains Stereophonic in this mode.

Important Note: This mode can produce sustained
oscillations if the feedback control is set too high.

• [*=1]Overload Indicator: This indicator lights up in red when the Echo Effect system is overdriven. If this occurs, back down on the level or mix controls to prevent clipping distortion from occurring.

Ancillary Echo Effect Controls:

1. [*=1]Low Pass Echo: This inserts a 7 kHz Low Pass Filter in the Effect Signal Path. [*=1]High Pass Echo: This inserts a 5 kHz High Pass Filter in the Effect Signal Path. [*=1]Invert Echo: This phase inverts the Effect Signal. [*=1]Bandpass Echo: This is achieved by checking both the Low Pass and High Pass Echo checkboxes. It produces a Bandpass response having corner frequencies of 2 kHz to 8 kHz and is inserted into the Effect Signal Path.