Surround speakers
To convert a standardstereo installation intoa surround soundsetup, at least threeadditional speakersare needed, of whichthe centre one mustbe magneticallyshielded. The miniaturespeakers describedin this articlehave been designedsolely for this purposeby the German loudspeakerspecialistVisaton.
The surround-sound decoder publishedlast year proved very popularwith readers from all over the world.Many of them wrote, however, to askabout suitable loudspeakers.Since many of these readers expresseda wish to build the boxes themselves,it was a godsend when the Germanfirm of Visaton offered a set ofminiature loudspeakers for review.These speakers have been designed especiallyfor surround-sound applicationsand are available as kits at veryreasonable prices.The centre loudspeaker, whichshould be placed immediately underneaththe television set, uses magneticallyshielded drive units. This is a must,otherwise the TV sound and vision willbe adversely affected (and how!).Shielded drive units for home constructionare still few and far between.The back speakers have a novel facility.From their own tests, Visatonknew that the directional sensitivity ofthese speakers had an important effecton the optimum location of the listener.The pair discussed in this articlebeam upwards, which gives them amore diffuse character, and this inturn enlarges the listening area of op- timum surround effect. A simple, buteffective solution.
Complete surround-sound installationconsists of the power amplifier(s),surround-sound decoder, the standardloudspeakers for the left-hand andright-hand channels, a centre speakerthat is placed between these two, andtwo back speakers that provide thespatial information. The standardspeakers must be of hi-fi quality, sincethey largely determine the overallsound quality; they are normally drivenby the extant a.f. amplifier.