Listen to at least the first 5 minutes of King Tubby's "King at the Control." He is one of the pioneers of reggae and the use of dub delays. Pay attention to the interesting sounds that are created. You might recognize some sounds that appear to be delays, but there's something else going on—feedback!  ## What is Feedback Feedback is essentially when the output of a system is looped back into its input. In live sound situations, this is often considered a bad thing because it means the microphone is picking up sound from the speaker, creating a feedback loop where the speaker gets louder and louder. This occurs when the feedback amount is greater than 100 percent. However, in delay effects, you can create a feedback situation where the feedback is less than 100 percent. In this context, the percentage indicates how many subsequent echoes are created by describing the loudness of each echo compared to the last. The delay time dictates the spacing of the echoes, and the feedback amount determines how loud each subsequent echo is (and therefore how many echoes exist). Since the feedback is less than 100 percent, each echo will be quieter than the previous one, avoiding the problematic feedback that occurs when a microphone faces a speaker. Instead, the sound will gradually taper off over time, creating a more controlled and musical effect. ![[image-1.png]] ## Feedback and Delay Times ### Longer Delays If the delay times are long, the echoes will be spaced further apart. With high feedback amounts, this can cause the sound to appear to last a really long time. For an example of this, listen to the end of Radiohead’s “Karma Police,” where the extended echoes create a lingering, atmospheric effect. ![[dub delays - longer delays.mp4]] ### Shorter Delays If the delay times are short, all of the echoes will be very close to each other. Even if the feedback percentage is high, the close spacing of the echoes means the sound won't be heard for very long. This creates a resonant, reverberant quality, adding a sense of space and depth to the sound without extending its duration significantly. ![[dub delays - shorter delays.mp4]] ## Feedback with Filters King Tubby uses a mix of shorter and longer delays with feedback, creating a variety of sounds. From 0:30 seconds onwards, you can hear a longer delay with feedback, but notice how the sound quality changes slightly. This happens because each subsequent echo is being filtered to remove the lower frequencies. You can achieve a similar effect by using the filters within your delay plugin. Here is an example of progressively cutting off the low frequencies. Notice how each echo becomes brighter as the lower frequencies are filtered out, creating a distinct tonal change over time.  ![[dub delays - low cut eq.mp4]] Here is an example of progressively cutting off the high frequencies. Notice how each echo becomes darker as the higher frequencies are filtered out, creating a warmer and more subdued tonal change over time. ![[dub delays - high cut eq.mp4]]