Q ACOUS­TICS CON­CEPT 500 LOUD­SPEAK­ERS

How good does a de­sign have to be to win a ‘Loud­speaker of the Year’ award? Here’s where you find out….

Australian HIFI - - CONTENTS -

Iwas quite taken by sev­eral of the state­ments in the Own­ers’ Man­ual pro­vided with the Con­cept 500 speak­ers. One of them was: ‘ Speaker po­si­tion­ing in a room is not an ex­act sci­ence. Even ex­perts will find it nec­es­sary to ex­per­i­ment.’ An­other was: ‘ Try to achieve the best bal­ance be­tween bass quan­tity ver­sus qual­ity and vo­cal qual­ity ver­sus in­tel­li­gi­bil­ity.’ These are the best two bits of ad­vice I have ever read in an Own­ers’ Man­ual, and I am guess­ing that the man be­hind these words is none other than Karl-Heinz Fink, founder and owner of Fink Con­sult­ing, the com­pany which is pri­mar­ily re­spon­si­ble for de­sign­ing loud­speak­ers bear­ing the Q Acous­tics brand name.

Un­like many loud­speaker man­u­fac­tur­ers, which do not men­tion Fink Con­sult­ing’s in­volve­ment in their de­signs (I’m think­ing about Mis­sion’s LX range and its high-end Pi­las­tro, Tan­noy’s Mer­cury and Rev­o­lu­tion ranges, and Mor­daunt-Short, to name just three) Q Acous­tics is quite happy to ad­ver­tise its re­la­tion­ship with Fink. And why not? Ac­cord­ing to Ke­tan Bhara­dia, of What Hi-Fi magazine, Fink Con­sult­ing is: ‘ the most im­por­tant speaker com­pany you’ve never heard of.’

The equip­menT

They say beauty is in the eye of the be­holder, and to my eyes, the Con­cept 500s are truly beau­ti­ful loud­speak­ers. The very first thing that caught my eye was the cir­cu­lar (well, al­most cir­cu­lar!) chrome-coated cast alu­minium bases that sup­port the speak­ers. I’ve never seen such a de­sign used on a speaker, and I just love the way it looks. I love it so much that I wish Q Acous­tics had been a bit braver and made the base a com­plete cir­cle, so it pro­truded from the front and rear of each speaker as well as from the sides. (As de­signed, the base is ‘flat­tened’ where it passes un­der­neath the front baf­fle and the rear panel. As well as look­ing great, the base also gives ex­cel­lent side-to-side sta­bil­ity, so de­spite their not-in­con­sid­er­able height (1175mm) the Con­cept 500s are very sta­ble.

But if you lift your eyes from the alu­minium bases, you’re set for even more gor­geous­ness, ap­par­ently the brain-child of Fink Con­sult­ing de­signer Ke­iron Dunk. First, there aren’t any sharp edges in sight… all edges are beau­ti­fully rounded. Then there’s the colour scheme, which on my sam­ple was a front baf­fle of such deep high-gloss black­ness that you could be look­ing into a shiny black hole. This su­perb black fin­ish ex­tends along the sides and top of the cabi­net for three-quar­ters of the way, af­ter which it tran­si­tions to a rose­wood wood-grain fin­ish that then en­tirely cov­ers the rear baf­fle. So when you’re look­ing at the speak­ers from the rear, it ap­pears that they have a high-gloss rose­wood fin­ish, whereas when you look from the front, it ap­pears that the speak­ers are fin­ished in gloss black. It’s only when you view the speak­ers from the sides (or from the three-quar­ter views) that you re­alise you’re get­ting a bit of both. Q Acous­tics also makes the Con­cept 500 avail­able in a gloss white/pale oak combo, which I think looks even bet­ter again, but ob­vi­ously that’s al­ways go­ing to be a per­sonal call! I can say this with some author­ity, be­cause although I loved the look of these speak­ers, I did re­ceive a few com­ments that the de­sign was ‘too mod­ern’… so some tra­di­tion­al­ists might not ap­prove of it.

That the Con­cept 500s are so sta­ble is good, be­cause not only are they not small, they’re not light ei­ther, with each speaker tip­ping the scales at 42kg. This size and weight is mostly due to the fact that the Con­cept 500 uses Q Acous­tics’ ‘gel-core’ cabi­net con­struc­tion, which is mostly com­prised of three lay­ers of MDF, with non-set­ting ‘gel’ sand­wiched be­tween the lay­ers. Q Acous­tics claims that its gel­core con­struc­tion tech­nique re­duces cabi­net res­o­nances by an av­er­age of more than 6dB over the midrange and more than 10dB at high and low fre­quen­cies. The idea is that vi­bra­tions in one layer of MDF are not trans­mit­ted to the next layer, be­cause the gel ma­te­rial (which also acts as an ad­he­sive, to bond the pan­els to­gether) ab­sorbs any vi­bra­tions, or—as Q Acous­tics’ prod­uct brochure puts it—‘ al­lows the ki­netic en­ergy gen­er­ated by the drive units within the cabi­net to be dis­persed as heat, pre­vent­ing them colour­ing and de­grad­ing the speaker’s mu­si­cal out­put.’

The gel-core con­struc­tion ex­plains the weight of the cabi­net, but the size is nec­es­sary be­cause the in­ter­nal vol­ume of the cabi­net is a crit­i­cal fac­tor in de­ter­min­ing the low-fre­quency re­sponse of the Con­cept 500 (or any loud­speaker, for that mat­ter), which Q Acous­tics spec­i­fies at 41Hz. Be­cause the cabi­net walls are so thick, the de­sign­ers have had to make the out­side di­men­sions of the cabi­net much larger in or­der to de­liver the re­quired in­ter­nal vol­ume. The size is also be­cause of the in­ter­nal vol­ume used up by the amount of in­ter­nal brac­ing that’s been used in the Con­cept 500—brac­ing that Q Acous­tics has trade-marked as ‘P2P’ (‘Point to Point’) brac­ing. But there’s yet an­other rea­son for the size of the cab­i­nets.

They say beauty is in the eye of the be­holder, and to my eyes, the Con­cept 500s are truly beau­ti­ful loud­speak­ers

They also con­tain ‘pres­sure equalis­ers’, which are col­umns filled with ab­sorp­tive ma­te­rial that have been ‘tuned’ to damp res­o­nances in­side the cabi­net… or, if you like, equalise in­ter­nal air-pres­sure vari­a­tions. The pres­sure equalis­ers could be nec­es­sary be­cause of the height of the speak­ers, and/or the lo­ca­tion of the bass/midrange driv­ers and/or the size of the bass re­flex port (about which more later).

In the Con­cept 500 de­sign, as in other of its ‘gel-core’ de­signs, Q Acous­tics has also me­chan­i­cally de­cou­pled the 28mm soft dome tweeter from the gel-core cabi­net by means of a flex­i­ble mount­ing ring. I am a great fan of iso­lat­ing tweet­ers in this fash­ion, be­cause the per­for­mance of a tweeter can be dra­mat­i­cally al­tered by cabi­net vi­bra­tions. By way of ex­am­ple, con­sider this ex­treme ex­am­ple: To de­liver an au­dio sig­nal at 10kHz, a tweeter dome has to move back and for­ward ten thou­sand times ev­ery sec­ond, and this for­ward/back­ward move­ment amounts to only a few mi­crons of travel. So if a loud­speaker cabi­net is also vi­brat­ing at 10kHz (sym­pa­thetic vi­bra­tion caused by the tweeter it­self), and it goes ‘back­wards’ at the same mo­ment the tweeter’s dome goes ‘for­wards’, the dome’s net move­ment would be zero, so you wouldn’t hear any­thing at all. It’s for this rea­son that Q Acous­tics is far from be­ing the first to iso­late a tweeter from a front baf­fle… but it must be said that the prac­tise of iso­lat­ing tweet­ers from baf­fles is not yet com­mon, (though in­creas­ingly so in re­cent years) be­cause of the in­creased costs in­volved and the ad­di­tional dif­fi­cul­ties it cre­ates dur­ing the man­u­fac­tur­ing process.

De­spite the size of the cab­i­nets, the Con­cept 500 is a three driver, two-way bass re­flex de­sign, us­ing quite small-di­am­e­ter bass/ midrange driv­ers. When I say ‘quite small’, Q Acous­tics lists their di­am­e­ter at 165mm. I’m not sure how it ar­rived at this fig­ure, be­cause I mea­sured the over­all di­am­e­ter—as mea­sured on the front baf­fle—at just 154mm. The to­tal mov­ing di­am­e­ter is 142mm and the Thiele/ Small di­am­e­ter is 130mm, which gives a sur­face area (Sd) of 133cm². This means that if the bass were be­ing de­liv­ered by a sin­gle driver, rather than two, it would have an Sd of 266cm², which would trans­late to an over­all driver di­am­e­ter of around 204mm.

The cones of the bass/midrange driv­ers are made from coated pa­per rather than from ther­mo­plas­tic, which will please the tra­di­tion­al­ists, as it’s rather stan­dard. What is not so stan­dard—and also not ob­vi­ous—is that they have 35mm di­am­e­ter voice coils, which are rather larger than the usual 25mm di­am­e­ter voice-coil one would nor­mally ex­pect to find on a driver of this size. The larger di­am­e­ter means more turns on the for­mer, giv­ing in­creased con­duc­tor in the gap for bet­ter drive, and also means bet­ter power-han­dling ca­pac­ity. The in­creased area of the coil sur­face also means bet­ter cool­ing, so less chance of any com­pres­sion ef­fects. The wire it­self is cop­per clad alu­minium and the for­mer glass-fi­bre. The roll sur­round is rub­ber, rather than the pop­u­lar (but prone to dis­in­te­gra­tion) foam that is of­ten used as a cost-saver by some man­u­fac­tur­ers.

The two midrange driv­ers and the tweeter are ar­rayed in ‘MTM’ fash­ion (with the tweeter mid­way be­tween the two bass/midrange driv­ers). The small fab­ric cloth grille is stretched over a plas­tic frame and se­cured in place on the front baf­fle by small hidden mag­nets (hidden on both the grille frame it­self and the front baf­fle).

The bass re­flex port, lo­cated low down on the rear panel, is very large, with a di­am­e­ter of 100mm and a tube length of 170mm. The port is made from pre-formed ther­mo­plas­tic and is rounded at both ends to re­duce tur­bu­lence. As with many man­u­fac­tur­ers, Q Acous­tics pro­vides a foam bung that can be used to fully or par­tially block the port, but un­like many man­u­fac­tur­ers, Q Acous­tics pro­vides some very sen­si­ble ad­vice about how and when to use the bungs. The Owner’s Man­ual first ad­vises that the Con­cept 500 speak­ers are de­signed to work best when they’re be­tween two and four me­tres apart, at least one me­tre from side walls, and be­tween 600mm and one me­tre from rear walls. It then says: ‘ The closer the speak­ers are to the rear wall the more the bass fre­quen­cies will be re­in­forced un­til they over­whelm the over­all sound. In this in­stance clos­ing the rear port with the foam bung will tend to re­duce bass, which is use­ful when do­mes­tic cir­cum­stances de­mand that the Con­cept 500 is

The bass re­flex port, lo­cated low down on the rear panel, is very large, with a di­am­e­ter of 100mm...

used closer to a rear wall. En­sure that the bungs are fit­ted snugly into the port, but avoid in­sert­ing them too far. You will find the over­all level of bass is re­duced but bass ex­ten­sion and def­i­ni­tion will be in­creased. The op­ti­mal po­si­tion of the speak­ers will only be found through ex­per­i­men­ta­tion and by mak­ing small ad­just­ments dur­ing the first few lis­ten­ing ses­sions. The foam bungs come in two parts, so that they can be used to fully or partly close the rear port. Again, the op­ti­mum con­fig­u­ra­tion of the port can only be found by ex­per­i­men­ta­tion.’ So more good—and su­perbly com­pre­hen­sive—ad­vice from Q Acous­tics then!

Around the back of the Q Acous­tics Con­cept 500 is a plate with a two pairs of large, bi-wire­able ter­mi­nals, shorted by buss-bars for those au­dio­philes us­ing only a sin­gle set of speaker ca­bles. If you’re us­ing mul­ti­ple ca­bles to bi-wire the speak­ers, or you’re bi-amp­ing, you should re­move the buss-bars.

Up high on the rear of the cabi­net is a very large plate which, if you re­moved it, would re­veal that the PCB-mounted cross­over net­work is at­tached to the rear of it. On the plate are three small holes. These are pro­vided so you can ad­just the level of the high-fre­quen­cies to suit your room by in­sert­ing a link be­tween the mid­dle and the right-hand hole, or be­tween the mid­dle and the left-hand hole. For ex­am­ple, if you link the cen­tral hole with the right hole, us­ing the ‘jumper’ bar pro­vided by Q Acous­tics, you will in­crease the level of the high-fre­quen­cies de­liv­ered by the tweeter, which you might do in or­der to com­pen­sate for a room that’s very acous­ti­cally ab­sorp­tive due to the pres­ence of thick car­pets and/or soft fur­nish­ings.

Con­versely, if you have a bright-sound­ing room be­cause of the pres­ence of lots of glass or other hard acous­ti­cally-re­flec­tive sur­faces, you can re­duce the level of the highs by not link­ing any of the holes. If you have a room that’s nei­ther ab­sorp­tive nor re­flec­tive, you’d in­sert the ‘jumper’ bar into the cen­tral and left-most holes (about which more in a mo­ment).

It is very im­por­tant to note that although the con­struc­tion sug­gests that the ‘jumper’ might be an en­cap­su­lated re­sis­tor (as used by some high-end man­u­fac­tur­ers), it isn’t. It’s just a sec­tion of bent steel, with 0 re­sis­tance, around which is a ‘grip’ to make it eas­ier to in­sert and re­move. So don’t go try­ing to use re­sis­tors in­stead of the sup­plied ‘jumper’ bars!

IN USE AND LIS­TEN­ING SES­SIONS

Be­fore telling of my lis­ten­ing ex­pe­ri­ences with the Con­cept 500 speak­ers, I have a con­fes­sion to make, which is that when au­di­tion­ing speak­ers, I rarely read the Owner’s Man­ual. The rea­son I am mak­ing this con­fes­sion is that when I first fired up the Con­cept 500s, my im­me­di­ate im­pres­sion was that the high fre­quen­cies were a lit­tle light-on. ‘ Maybe the speak­ers need a bit more run­ning-in time,’ I thought to my­self. A week later, the bass and midrange had def­i­nitely ben­e­fited from the ad­di­tional run­ning-in time, but I thought that the treble was still a tad di­min­ished.

Now as it hap­pens—and as men­tioned pre­vi­ously—the level of the Con­cept 500s high fre­quen­cies can be ad­justed by means of in­sert­ing short­ing links on the rear panel. The speak­ers are sup­plied with­out the links in place, and I had naively as­sumed that this was the nor­mal ‘de­fault’ set­ting for the tweeter. I was wrong. It turned out that this is the ‘less treble’ set­ting, so I was hear­ing ex­actly what the de­sign­ers had in­tended: less treble. Need­less to say, when I in­serted the links (one in each speaker) to connect the mid­dle ter­mi­nal to the one to the left of it, the level of treble was then de­liv­ered at a level that I found not only com­pletely sat­is­fac­tory, but also beau­ti­fully balanced with that of the bass/midrange driv­ers.

One of the first tracks I played in or­der to eval­u­ate the bass per­for­mance of the Con­cept 500s was Fel­low Crea­tures from bassist Jasper Høiby’s al­bum of the same name (though I use the word ‘al­bum’ loosely, since you can down­load hi-res tracks in­di­vid­u­ally if you like). Why Høiby? Well if you can’t trust a com­poser whose pri­mary in­stru­ment is dou­ble-bass to give him­self some great bass lines and mu­sic that ex­plores the outer lim­its of what a dou­ble-bass can do, who could you trust? Høiby de­liv­ers in spades of course, us­ing his mighty in­stru­ment’s full fre­quency range and full dy­namic range, and all the play­ing tech­niques at his dis­posal. I could eas­ily hear that the Con­cept 500s are dig­ging deep far into the bass, and de­spite the ex­tremely low pitches be­ing re­pro­duced, the sound was still tune­ful and melodic and there was no un­wanted dou­bling. That beau­ti­ful ‘stringy’ bass sound you hear in live per­for­mance is clearly au­di­ble.

The clar­ity of Høiby’s dou­ble bass is even more au­di­ble on the in­tro to Col­lec­tive Spa­ces, a track that’s also high­lights Mark Lockart’s sax­o­phones and Laura Jurd’s trumpet. Cor­rie Dick’s work on drums is a stand­out on this track, and you can hear the bounce of his pedal on the kick drum and the siz­zle of the sound of his tapped cym­bals. You can also hear the acous­tic around the cym­bals, which kinds of gives away how they were recorded, but also shows how re­veal­ing the Con­cept 500s are of record­ing tech­nique.

The Q Acous­tics Con­cept 500s pro­jec­tion with vo­cals was im­pec­ca­ble. Lis­ten­ing to Matilda, from Pete Cullen’s ‘Salt­wa­ter Cow­boy’, Cullen’s dis­tinc­tive quin­tes­sen­tial Aus­tralian drawl leaps from the speak­ers as if he were cradling his man­dolin in your liv­ing room.

www.avhub.com.au

I love it so much that I wish Q Acous­tics had made the base a com­plete cir­cle, so it pro­truded from the front and rear of each speaker as well as from the sides...

The cones of the bass/midrange driv­ers are made from coated pa­per rather than from ther­mo­plas­tic, and have 35mm di­am­e­ter voice coils, rather larger than thel 25mm di­am­e­ter voice-coils one would ex­pect .

Newspapers in English

Newspapers from Australia

© PressReader. All rights reserved.