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Articles March-April-May-June 2020

The Art and Craft of Sound Design- Interview with Bishwadeep Chatterjee

PT met up with Bishwadeep Chatterjee, one of India’s most esteemed Sound Designer. In this extremely insightful interview, he generously shares his unique perspective and experience on music recording and sound design..... read more

Bose Professional Assures an IMMERSIVE SOUNDSCAPE At Sardar Patel Stadium – The Largest Cricket Stadium in the World

US President Donald Trump and First Lady Melania Trump were welcomed by Prime Minister Narendra Modi as they arrived for the “Namaste Trump” event on 24 Feb 2020..... read more

Shankar and Siddharth Mahadevan’s Lambodara Studios – Leaves you Breathless

Auroville based leading acoustic consultancy & audio video system design firm Sound Wizard was tasked with designing acclaimed singer, composer and music director Shankar Mahadevan’s ..... read more

In Conversation With Sreejesh Nair

Besides being a part of the first Dolby Atmos Mix theater installation in India and the first Dolby Atmos Premiere Mix room in the world, Sreejesh Nair has been responsible for crafting the sound for major films like Bombay Velvet, Gangs of Wasseypur - II, Agneepath..... read more

Stained Class Productions - Beyond the Realms of Sound

Meet the father & son duo, Murugan N. and Mrinal N. whose musical influence has been Judas Priest and who have aptly named their studio after the fourth studio album of Judas Priest - Stained Class. Mrinal who manages the technical aspects ..... read more

Independent Producers Blurb on their Music and Technology

One of Asia’s largest music festivals, OPPO Sunburn in association with Percept Live and Klassique Events Goa returned to its birthplace Goa, this December after a hiatus of 3 years. The festival which made a grand homecoming for its 13th edition at Vagator for a three-day showcase ..... read more

Sequence of Steps to Follow on Resuming Studio Operations Post an Extended Duration of Shutdown

Munro Acoustics India has put together a suggestion/ guideline document after consulting many studios and engineers across the world to aid their clients in the Indian Subcontinent, Middle East and SE Asia..... read more

Acoustic and Audio System Design for Small Rooms - Part 1

Acoustic and audio system design for a “small room” can be extremely challenging, especially for critical listening applications like control rooms and reference home cinemas. It is vital to understand the relationship between system..... read more

Harman Reigns Supreme in Indian Cinemas

Sound in the cinema, until recently, was dictated by standardized speaker layouts. If you are from the commercial cinema project, from the first design to the finished furnishings..... read more

Recording To Records

Music in India has changed drastically. This music and song driven country which is largely dominated by Bollywood soundtracks, has in the past year seen less of originals and more of old songs being plagiarised..... read more

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Acoustic and Audio System Design for Small Rooms - Part 1

By - Rahul Sharma, CEO, Menura Acoustic Labs In collaboration with Sound Wizard





Acoustic and audio system design for a “small room” can be extremely challenging, especially for critical listening applications like control rooms and reference home cinemas. It is vital to understand the relationship between system design and acoustics, and to accept that neither aspect can be designed in isolation without considering the needs and requirements of the other. In this six part educational series, we will outline many important “small room” design considerations and along the way demonstrate how to effectively tackle common acoustical and system design problems


Small Rooms

Let us start by defining a “small” room, firstly so that you aren’t utterly disappointed at the end of the series, and secondly because understanding the distinction between small and large rooms is the key to digesting the completely different design approaches to both. In an attempt to keep theory to a minimum, lets just say that small rooms are those where the room boundaries are close enough to create modal issues in the lower frequencies. Extensive low frequency absorption is usually required, and since the first reflections of sound from room boundaries reach the listener extremely quickly, a great deal of care must be taken to prevent early reflections from colouring the direct signal. As a rule of thumb, a room whose largest dimension is under 20m or 65 ft can be considered to be a small room

In the first part of this series, we will focus on three basic acoustic and psychoacoustic phenomena whose understanding are critical to effective design; the Haas effect, comb filtering and phase shift.


Fig.1: The Haas Effect


Haas Effect

The simplest way to describe the Haas effect is through its other name, the precedence effect. If two sources of sound are separated in arrival time by less than approximately 40ms, they are perceived as one. Because of this, both sounds also appear to come from the same location, which ends up being the physical location from which the first sound reaches your ears. Because of this powerful psychoacoustic phenomenon, your brain locks into this physical location, and it then becomes very difficult for your brain to reset and convince itself that there are in fact two separate sources of sound in different locations.

Either the level of one has to be reduced significantly, or it has to be delayed by over 40ms. The implication of the Haas effect in small rooms is straight forward; your brain is unable to separate the direct signal from early reflections because the arrival times are too close together! Why is this bad? The short answer is comb filtering, but the concept of phase shift needs to be understood before we openthat can of worms.


Fig.2: Amplitude, Time Period and Frequency of a Wave


Phase Shift and Comb Filtering

As audio professionals, most of us are aware that every audible (and inaudibile) frequency has a corresponding wavelength. The time period defines the time it takes for one complete oscillation over that wavelength. While most audio signals are complex and never resemble a sine wave, we will still use one to illustrate our concept.

In the image below, two audio signals with the same amplitude (level), frequency response and wavelength BUT different arrival times have been added. Because of the different arrival times, the combination of constructive and destructive interference results in the “combing” you see in the image below. As you can imagine, this is not a desirable result.


Fig.3: Combing


The time delay created a phase shift in the wave, which combined with the original signal. Thanks to the Haas effect, this is the resultant wave we hear in a room. We sometimes mistakenly attribute the resultant wave to the audio system alone, when in fact it is a combination of the room and source. The colouration affects the spectral content of the sound waves, which goes against the main design goal of any listening space – transparency. The solution is to create a reflection-free zone, both through acoustic treatment and/or angling the walls of the listening room. Stay tuned as we dive deeper into acoustic and audio system design considerations for “small” rooms!

www.menuralabs.com

info@menuralabs.com


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