Australian HiFi – May 2019

Australian Hi-Fi 33

Revel Performa F228Be Loudspeakers

this,butaddinga qualifierthatitsminimum

impedanceis 3.4Ωat90Hz.Asit stands,

underEuropeanIECregulations,theRevel

F228Beis a verydefinitelya 4Ωsystem.

NewportTestLabs’measurementofthe

RevelF228Be’ssensitivitycameinratherlow-

erthanRevel’sspecificationof90dBSPL,with

thelabmeasuring88dBSPLusingitsstandard

technique.Thisis almosttobeexpected,as

NewportTestLabs’techniqueis verystrin-

gent,anddoesn’tdoanyspeakersundertest

anyfavours,butlargefloor-standersmostly

doquitewell,sothe2dBdisparityis a little

surprising.However,despitethisresult,the

88dBSPLsensitivitymeansthattheRevel

F228Beis actuallymoreefficientthanthe

averagehigh-qualityfloor-standingspeaker

(thataveragebeing87dBSPL).

Graph6 is a compositegraphthatshows

thevariousdifferentmeasurementsmadeby

NewportTestLabsontheonegraph,soyou

canseetheoverallintegration.(Notethatthe

blacktracestopsat20Hzsimplybecauseno

datawasmeasuredbelow20Hzforthispar-

ticulartrace.)Thetracesforthebassdrivers

andthereflexportsuggestthatthemeasured

low-frequencyresponseoftheRevelF228Be

couldhavebeenimprovedhadthelabposi-

tionedthespeakerundertestclosertoa room

boundary.

NewportTestLabsmeasuredtheRevel

F228Beashavinga superblyflatandextend-

edfrequencyresponseandabove-average

efficiency.Itsoveralllowimpedanceand

onedifficultphaseanglearesomethingof

anAchilles’Heel, meaningthatit willbea

tougherloadfortheamplifierdrivingit than

it mightotherwisehavebeen,butI wouldex-

pectanyonewhobuysa pairofRevelF228Bes

wouldalsoowna well-designedamplifierca-

pableofdeliveringthree-figurepoweroutput

intoa 4Ωload.Overall,theF228Beis a great

exampleofsuperiorspeakerengineering...

butI reallywouldn’thaveexpectedanything

lessfromRevel. Steve Holding

Graph6.Compositeresponseplot. Red traceis outputof bass reflexport.Darkblue

traceis anechoicresponseof bass driver.Pink traceis sine responseof midrangedriver.

Blacktraceis splicedresponsefromGraph5.

Graph5.Frequencyresponse.Tracebelow1kHzis the averagedresultof nine individ-

ual frequencysweepsmeasuredat threemetres,with the centralgrid pointon-axis

with the tweeterusingpink noisetest stimuluswith captureunsmoothed.This has

beenmanuallyspliced(at 1kHz)to the gatedhigh-frequencyresponse,an expanded

viewof whichis shownin Graph2.

Graph1.Averagedin-roomfrequencyresponseusingpink noisetest stimuluswith

captureunsmoothed.Traceis the averagedresultof nine individualfrequencysweeps

measuredat threemetres,with the centralgrid pointon-axiswith the tweeter.

Graph3.Low frequencyresponseof front-firingbass reflexport (red trace),combined

LF drivers(blacktrace)and midrangedriver(bluetrace).Nearfieldacquisition.Port/

wooferlevelsnot compensatedfor differencesin radiatingareas.

Graph2.High-frequencyresponse,expandedview,showingresponsewithoutgrille

(blacktrace)and with grillefitted(red trace).Test stimulusgatedsine. Microphone

placementthreemetreson-axiswith dometweeter.Lowermeasurementlimit 600Hz.

Graph4.Impedancemodulusof system(blacktrace),low frequencysection(green

trace),high frequencysection(red trace)plus overallphase(bluetrace).

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