Spatial Effects and Their Uses in Dub

In order to investigate how the spatial effects used in dub have influenced other genre first we must define what effects are used to create the illusion of space and how they have been used in dub.

Reverberation is the most commonly used effect used to create space. Izhaki (2012 pg.405) describes reverb in the following way, 

“In nature, reverb is observed mostly within enclosed spaces, such as rooms. Reverbs are easier to understand if we imagine an impulse sound, like a hand clap, emitted from a sound source in an empty room. Such a sound will propagate in a spherical fashion and for simplicity we should regard it as travelling in all directions. The emitted sound will travel in a direct path to a listener (or a microphone) followed by reflections that bounced from the walls, floor and ceiling. These will be gradually followed by denser reflections that have bounced many times from many surfaces. As sound both diminishes when travelling through air and being absorbed by surface materials, the reflections will slowly decay in amplitude. Reverb is the collective name given to the sound created by bounced reflections from room boundaries (which we consider to be the main reverb contributors, although in a room there might be many surfaces). In mixing, we use reverb emulators, either hardware units or software plugins, to simulate this natural phenomenon.” 

“Each time a waveform reflects some energy is absorbed by the surface and each time a waveform is diffused the energy is divided among the reflections and so over time the amplitude of reverberation decays until it is inaudible. As sound takes time to travel around a room (344meters per second at room temperature) each reflection arrives at the listener later than the last reflection and so the reverberation is audible for a longer period of time than the direct original sound. Diagram 1 below shows the decay of reverberation overtime.” (http://www.magicmess.co.uk/electronics/spring.php)

The amount of reverb in a space is dependent on the volume of the room but also the rate at which sound is absorbed by walls and other surfaces.

Wallace Sabine did some pioneering research in this area and came up with a formula that relates the quality of a room’s acoustic with the size of the room, and the amount of sound absorption surfaces present.

His formula calculates the reverberation time which is defined by the time taken (in seconds) for a sound to drop by 60 decibels.

RT60 = 0.161(V/Sa)

V is the volume of the room in cubic meters. This is divided by the total absorption of the room expressed in Sabines which is calculated by the sum of all the surface areas in the room multiplied by the absorption coefficients for each material.

A characteristic dub reverb sound is the spring reverb. The spring reverb works by using the physical movement of a spring to generate the reflections.

Spring Reverb Demo

Delay is another common effect used to create space in audio recordings. Hodgson (2010 pg.124) states “the simple delay line is the building block of all delay processing techniques.” Then continues to describe how audio signals are fed into a delay line where the signal is split and a copy is stored for a certain amount of time before being passed to the output after the direct signal.

All delay units and plug-in effects have 3 basic settings which are the Delay time or the amount of time between the input signal and the copy arriving at the output. The mix setting which adjusts the balance between the input signal and the delayed copy. And the feedback which controls the amount of the delayed signal which is routed back to the input. Hodgson (2010) states that recordists have created a “staggeringly diverse array of musical techniques” by adjusting the 3 parameters listed above.

 A common delay sound used in dub is the tape delay. Case (2007 pg.224) states that

“Before the days of digital audio, a common approach to creating delays was to use a spare analogue tape machine as a generator...During mixdown the machine is constantly rolling in record mode. The signal is sent from the console to the input of the tape machine...That signal is recorded at the tape machine and milliseconds later is played back...(the tape machine) remains in repro mode so the output is what it sees at the playback head...The signal goes in gets printed onto tape the tape makes its way from the record head to the playback head (taking time to do so) and finally the signal is played back off tape and returned to the console. The result is tape delay.” 

Analogue tape delay also adds tape saturation and tape hiss, these sounds have also become a highly sought after additional qualities of tape delay. Many hardware and software emulators try to recreate these qualities of tape delay and one such emulator used significantly in the production of dub is the Roland RE 201 Space Echo which uses a magnetic tape loop to simulate tape delay.

Roland RE 201 Space Echo

Another aspect of the use of space is creative sound staging. Moylan (2008) states "The sound stage is the singular area occupied by all of the sound sources of the music, as an aggregate or group.  It has an apparent physical size of width and depth that are defined at the level of the individual sound source: (1) the dimension of width is defined by the furthest right and left sound (lateral localization) and (2) the dimension of depth is defined by the most distant sound source and the closest sound source."

Zagorski-Thomas (2010) takes this idea of the sound stage further to functional staging “Functional staging is a concept building on the idea of phonographic staging developed by William Moylan and Serge Lacasse and related to Allan Moore’s ‘sound-box’. The staging of sounds in the record production process is considered to be functional if the reason for their particular placement or treatment is related to the practicalities of audience reception rather than to aesthetics.” (Zagorski-Thomas 2010 pg.1) 

“Functional staging relates to the size of the perceived space and the perception of distance rather than lateral placement.”  (Zagorski-Thomas 2010 pg.6)  

References and Bibliography

Case. A. (2007) Sound FX: Unlocking The Creative Potential Of Recording Studio Effects

Hodgson. J. (2010) Understanding Records: A Field Guide to Recording Practice. Continuum International Publishing, New York.

Izhaki. R. (2012) Mixing Audio: Concepts Practices and Tools. 2nd Edition. Focal Press

www.magicmess.co.uk/electronics/spring.php (Accessed 27/10/12)

Moylan. W. (2008) Considering Space in Music. (Accessed 21/09/12) http://www.artofrecordproduction.com/content/view/180/109/

Zagorski-Thomas. S. (2010). The stadium in your bedroom: functional staging, authenticity and the audience led aesthetic in record production. Popular Music, 29, pp 251-266.