Audio Effects – Reverb & Delay

August 25, 2006

Audio effects, we all know what they are, sort of. They are used to manipulate audio in ways that are not available with traditional playing and recording techniques. If you’re like me, and enjoy dabbling in audio production, you’re probably familiar with all the basic effects. Reverb is one of them, and probably the most easy to explain; it adds space to your audio. Delay on the other hand, is a little bit more difficult to explain. Again, if you’re like me, you want to fully understand how these effects work, so that when you go to use them you know them inside and out. Today’s article we will be discussing reverb and delay, how they work and why they work the way they do.



Sound produced in an enclosed space, reflects off of surfaces and blends together, creating reverberation (reverb for short). So, basically, reverb is the reflection of sound waves from a solid surface to our ears. It is most easily identified when the sounds stops, but you continue to hear the reflections as they decrease in amplitude. Large rooms or chambers are some of the best producers of natural reverb. There are a few different types of electronic reverberation mechanisms that produce reverb artificially. There types are:


1.        Plate reverberators – This type of reverb uses large metal plates suspended by strings, which are in turn inside of damped cases to manufacture the effect. Transducers are used to apply a signal to the plates, and electronic pickups are then used to convert the plate’s vibrations to an electric signal.

2.        Spring reverberators – These reverberators are similar to plate reverberators, except instead of using plates, springs are used instead. Spring reverberators are often integrated in instrument amplifiers, and are considered to be the most artificial sounding reverb types.

3.        DSP reverberators – DSP reverb units use signal processing algorithms to create the reverb effect, using long delays, envelope shaping, and other processes. This type of reverb is the most widely used and the most flexible form of reverb.

4.        Chamber reverberators – This is the most “natural” form of reverb, but can also be made artificially. Chamber reverb is basically a room with solid walls, a loudspeaker at one end, and microphones at one end. The audio is played through the loudspeaker, bounced off of the walls, and then recorded by the microphones.



The basic delay effect records an input signal, and then plays it back after a set period of time. The first wave of delay used reel-to-reel magnetic recording systems and tape loops to produce the effect.


5.        Analog Delay – This was the first type of delay employed in the audio engineering field. One type of analog delay unit used magnetic tape as the recording and playback medium. Motors would guide the tape through the device, with different mechanisms modifying the effect’s parameters. The tape used in this type of delay would break down after a while, so the tape would have to be replaced from time to time to maintain fidelity of the audio. Other types of analog delay used magnetic drums, or spinning magnetic discs instead of tape as a storage medium for the audio information. The main advantage to these types was the increased durability of the storage medium.


6.        Digital Delay – This type of delay unit became popular in the late 1970’s. But, at the time, were only available in the form of an expensive rack mounted unit. The BOSS DD-2 changed that in 1984, as it was now available in the form of an affordable foot pedal. Digital delay works by sampling the piece of audio being processed, recording the bit to a storage buffer, and then playing back the bit of audio based on the parameters set by the person using the unit. There are many different types of digital delay units that offer different digital signal processing options, so I can’t really expound on anything in that area. But in my opinion, digital delay effects units seem to be the most powerful and flexible of the two types. Many guitar players use this effect, although some people believe that digital delay sounds a bit artificial compared to its analog counterpart.


This is the first part in my continuing series on audio effects. I’ll be covering some of the more standard effects first, like today’s subjects, and then move on to the more advanced effects later on. I hope that this shed some light on the subject, making your next foray into audio recording or editing a little easier and more fun.

  Jason Cole and DiskFaktory Mastering offer great professional mastering services and information regarding audio engineering and CD mastering in California. Get the professional mastering information you are seeking now by visiting


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