LAB­O­RA­TORY TEST RE­PORT

Australian HIFI - - ON TEST -

Newport Test Labs mea­sured the fre­quency re­sponse of the Revel Con­certa2 M16 speaker as 45Hz to 22kHz ±4dB, which is an ex­cel­lent re­sult and shown in Graph 1. You can see from this graph that the re­sponse is par­tic­u­larly flat be­tween 250Hz and 12kHz where, ex­cept for one small dis­crep­ancy cen­tred at 5kHz, it’s es­sen­tially within ±1dB. Also note that this is a very high-res­o­lu­tion graph with­out any smooth­ing—the hu­man ear would ac­tu­ally hear the in-room re­sponse that’s shown in Graph 5.

In Graph 2, Newport Test Labs has again used a high-res­o­lu­tion mea­sure­ment tech­nique and also ex­tended the high-fre­quency limit of the mea­sure­ment up to 40kHz. The peak at 23kHz is a res­o­nance caused by the use of alu­minium as a dome ma­te­rial. Luck­ily, be­ing at 23kHz it’s well above the limit of per­cep­tion for al­most all hu­mans, but even the few that could hear this high a fre­quency would be un­likely to be able to de­tect the peak, due to its very high Q. The same could be said for the ex­tremely sharp dip in re­sponse that fol­lows im­me­di­ately af­ter. The tweeter is cer­tainly a hi-res type, as demon­strated by its re­sponse ex­tend­ing eas­ily out to 40kHz, and by the look of it, likely far above this fre­quency.

This graph shows the dif­fer­ence in re­sponse be­tween us­ing the Rev­els with their grilles fit­ted (red trace) and with­out. Although there are some mi­nor dif­fer­ences, I doubt they’d be audi­ble, so I’d plump for lis­ten­ing with the grilles on to en­sure added phys­i­cal pro­tec­tion for the driv­ers.

Low-fre­quency re­sponse is mea­sured by Newport Test Labs us­ing a near-field tech­nique that sim­u­lates the re­sponse that would be mea­sured if the speaker were in an ane­choic cham­ber, and is shown in Graph 3. You can see the bass/midrange driver starts rolling off at 100Hz to a min­i­mum at 45Hz which is the ex­pected be­hav­iour for a small bass/ mid driver in a small-vol­ume bass re­flex en­clo­sure. What I didn’t quite ex­pect was the per­for­mance of the port, which rather than be­ing peaky is in­stead quite flat, de­liv­er­ing a sus­tained equal-vol­ume out­put from around 30Hz up to 70Hz. This would not only con­trib­ute to im­proved bass out­put, it would also mean the bass from the Con­certa2 M16 would sound dif­fer­ent to bass from a speaker with a con­ven­tional bass re­flex align­ment.

The im­ped­ance of the Revel Con­certa2 M16, as mea­sured by Newport Test Labs (Graph 4), shows that the speaker will re­quire your am­pli­fier to de­liver ad­e­quate cur­rent be­tween 120Hz and 270Hz, where the im­ped­ance is around 5Ω or lower, but this won’t be a par­tic­u­larly dif­fi­cult task be­cause the phase (blue trace) is rea­son­ably be­nign (±30°) across this fre­quency range. Don’t skimp on am­pli­fier power and make sure the am­pli­fier you use will com­fort­ably drive 4Ω loads. The im­ped­ance plot is oth­er­wise un­re­mark­able, other than to say there are no cabi­net res­o­nances, which is good, and the mod­u­lus is con­strained be­tween 4.2Ω and 28Ω, which is also good.

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