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.
According to Stereophile magazine, the top (‘A’ ranked) room correction or room EQ devices are the: Audyssey Sound Equalizer; Meridian 861 with MRC room correction; Rives Audio sub-PARC / PARC; SVSound AS-EQ1; Velodyne SMS-1 and the Z-Systems RDP-1 Reference. This article explores the pros and cons of each device from a purely functional perspective…here is an excerpt from the section on the SVSound AS-EQ1: “Designed for use with either single or dual subwoofers, the AS-EQ1 is based on a implementation of Audyssey’s DSP room EQ code. Plug in the included measurement microphone and install the custom Windows based software onto your computer and you are ready to go! Because it uses Audyssey code many locations in the room are measured (up to 32) before the correction filters are generated. This makes it particularly suitable for use in a multi-seat home theater where the bass response and therefore degree of correction required will vary significantly from seat to seat”
Meridian’s approach is one of the best I have found (both sound quality wise and theoretically) for electrically correcting the problems caused by a room. The Meridian digital room correction system follows the same high level process as other devices such as those by TacT and Audyssey (measure, compare, generate and then apply correction filters) […]