AV Expo

Articles May-June 2025

SISPL Elevates Caterpillar's Corporate Boardroom with World-Class AV Integration

Shared exclusively with AV-ICN Expo Magazine, this case study explores the team's dedication to deliver world-class communication and collaboration solutions to the client. read more

Illuminating Shopping Mall with Xtreme Media's Nyx Series LED Displays

This case study features Xtreme Media's successful execution in a shopping mall, where the use of LED display technology has transformed the mall into a vibrant and engaging space. read more

AV Installation: Glimpses

A Spotlight on AV Excellence Spanning India read more

Ansata and Studio One Together Transform Ambazari Garden into a Picturesque Landscape

Blending High-End Technologies with Thoughtful Execution, The Project Creates a Visual Feast for Ambazari's Visitors in Nagpur. read more

Imagination Meets Intent: How DoT Mavericks Crafted an Immersive Escape at COVAH

This feature shares an insightful story on how DoT Mavericks immerses COVAH's diners through projection mapping on the walls of COVAH. read more

Moxy Hotels Groove to the Sound of HARMAN Professional

KORE AV SOLUTION and HARMAN Professional engineered an innovative solution that harmonises with Moxy Hotel's spirited ambiance and modern aesthetics. read more

Articles Mar-Apr 2025

Lumina Screens Enhances Chennai Home Theatre with Cinematic Experiences

Cinema Meets AV Excellence with 165-inch Diagonal Accupix Pro for Chennai Home Theatre by Lumina Screens. read more

HARMAN Professional Synchronizes Cinematic Viewing with Sonic Beauty

HARMAN's Rich Acoustical Treatment of Movie Magic Theatre Blends Immersive Experiences with Impactful Acoustics. 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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