Sweet spot (acoustics)

The sweet spot is a term used by audiophiles and recording engineers to describe the focal point between two speakers, where an individual is fully capable of hearing the stereo audio mix the way it was intended to be heard by the mixer. The sweet spot is the location which creates an equilateral triangle together with the stereo loudspeakers, the stereo triangle. In the case of surround sound, this is the focal point between four or more speakers,^[1][2] i.e., the location at which all wave fronts arrive simultaneously. In international recommendations the sweet spot is referred to as reference listening point.^[3][4]

Different static methods exist to broaden the area of the sweet spot. A discussion of methods and their benefits can be found in Merchel et al.^[5] By means of such methods more than one listener can enjoy the sound experience as intended by the audio engineer, including the desired phantom source locations, spectral and spatial balance and degree of immersion. Alternatively, the sweet spot can be adjusted dynamically to the actual position of the listener. Therefore, a correct phantom source localization is possible over the whole listening area. This approach is implemented in the open source project SweetSpotter. Massive multi-channel audio systems that apply wave field synthesis or higher order ambisonics exhibit an extended optimal listening area instead of a sweet spot.^[6]

Sound engineers also refer to the sweet spot of any noise-producing body that may be captured with a microphone. Every individual instrument has its own sweet spot, the perfect location to place the microphone or microphones, in order to obtain the best sound.

References

1. Dolby Laboratories Licensing Corporation. "Dolby Surround Mixing Manual" (PDF). Dolby. pp. 2–7. Retrieved 1 June 2018.
2. Frank, Mathias; Zotter, Franz; Wierstorf, Hagen; Spors, Sascha (2014). "Spatial Audio Rendering". In Möller, Sebastian; Raake, Alexander (eds.). Quality of Experience. Advanced Concepts, Applications and Methods. T-Labs Series in Telecommunication Services. Springer. p. 250. doi:10.1007/978-3-319-02681-7_17. ISBN 978-3-319-02681-7.
3. "Multichannel stereophonic sound system with and without accompanying picture" (PDF). International Communication Union. International Communication Union. p. 2. Retrieved 1 June 2018.
4. "Methods for the subjective assessment of small impairments in audio systems" (PDF). International Communication Union. International Communication Union. p. 13. Retrieved 1 June 2018.
5. Merchel, S., Groth, S., Analysis and Implementation of a Stereophonic Play Back System for Adjusting the "Sweet Spot" to the Listener’s Position, Proceedings of 126th AES Convention, Munich, Germany, 2009.
6. Ziemer, Tim (2018). "Wave Field Synthesis". Springer Handbook of Systematic Musicology. Springer Handbooks. Berlin, Heidelberg: Springer. p. 329. doi:10.1007/978-3-662-55004-5_18. ISBN 978-3-662-55004-5.

Further reading

• Peters, Nils (2010). Sweet [re]production: Developing sound spatialization tools for musical applications with emphasis on sweet spot and off-center perception (PDF) (PhD). McGill University. Retrieved 1 June 2018.
• Martin, Geoff. "Introduction to Sound Recording". Retrieved 1 June 2018.
• Toole, Floyd E. (2007). "Making (Bass) Waves—Below the Transition Frequency". Sound Reproduction. Loudspeakers and Rooms. Burlington, Oxford: Elsevier. pp. 197–248. doi:10.1016/B978-0-240-52009-4.50017-4. ISBN 978-0-240-52009-4.