This weeks blog posts covers some of my favorite disks that I use when I am out at a customer’s house diagnosing their room’s unique acoustical issues or setting up their system. They have been chosen because they are high quality recordings that contain elements that are useful to test a system’s sound quality.
Studio Six Digital, makers of the AudioTools acoustic measurement software for Apple iOS, have created a free acoustic measurement app for JL Audio called, rather creatively, “JL Audio Tools”. In this blog post I’m going to walk you through the main features of the app. Once you’ve downloaded the app and launched it the first screen you see is the menu screen. The JL Audio Tools app does not have all the features of the paid-for Studio Six Digital Audio Tools app but does have many of them. The JL Audio app offers a Sound Pressure Level (SPL) meter, a Real Time Analyzer (RTA), a speaker polarity test and some handy audio calculators.
One of the things I get asked quite often is ‘where is the best place to put bass traps and why?’. This short article will explain a little about what bass traps do and how they work before going on to discuss the three different places where bass traps can be placed.
This article continues the theme of the last two blog postings in whic we outlined some ways in which subwoofers can be used to improve sound quality. Last week’s installment ‘Using Subwoofers to Improve Sound Quality: Part 2 Room Modes‘ outlined a technique whereby two subwoofers are positioned within a room to destructively drive a particular room mode, nullifying its frequency response peak and time domain ringing. This week we introduce the Welti / Devantier and Geddes multi-sub methodologies. Both involve using multiple subwoofers as a way to smooth bass response and reduce the impact of modal resonances.
Room modes are caused by perfect constructive interference between a sound wave traveling between two boundaries. This article provides a high level overview of room modes and their impact on sound quality. Two examples of how to use subwoofers to reduce the impact of these modes on sound quality are explained – placing the subwoofer in a pressure null and destructively driving a mode with two subwoofers.
Deep nulls in the frequency response in the bass region can be caused by phase cancellation between the direct sound wave from a sound producing device and the indirect sound wave that has reflected from a nearby boundary such as the floor, ceiling or walls. This phenomenon is called speaker boundary interference or SBIR for short. This article introduces SBIR and explains how these deep nulls can be ameliorated through use of a subwoofer.
Today I’m going to look at room correction products specifically designed to be used with subwoofers only. Included in this article is examination of products by Audyssey, Velodyne, DSPeaker and SVS.
In the next couple of articles I’m going to create a comprehensive directory of the room correction products available on the market and assess them against the functional criteria that have been explained in the last two articles (
here and
here). Today I’m covering Meridian (the 861 and G68 surround processors), TacT (including the 2.2XP) and Lyngdorf. Future articles will examine Audyssey, Velodyne and DSPeaker.
