TWO THI NGS A ROOM CORRECTI ON PRODUCT MUST DO
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ROOM CORRECTI ON My r esear ch has l ed me t he concl usi on t hat t her e ar e a number of basi c f unct i onal el ement s t hat ALL r oom cor r ect i on devi ces shoul d possess. These concl usi ons der i ve f r om a r oom acoust i cs desi gn vi ewpoi nt r at her t han a sound qual i t y per spect i ve. I t i s i nt er est i ng t hat t her e ar e many devi ces on t he mar ket t hat do not meet t hese t wo basi c cr i t er i a‌
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Must not appl y cor r ect i on f i l t er s above t he t r ansi t i on f r equency OR must al l ow t he user t o swi t ch of f r oom cor r ect i on above t he t r ansi t i on f r equency
THI NGS A ROOM CORRECTI ON PRODUCT MUST DO When a measur ement mi cr ophone i s pl aced at t he l i st eni ng pos i t i on( s ) and t he sour ce i s a r easonabl e di st ance away ( e. g. 8f t ) what we see on a f r equency r esponse char t abov e ar ound 300Hz ( t he t r ansi t i on f r equency) i s a combi nat i on of t he di r ect sound f r om t he speaker s and t he r ef l ect ed sound f r om t he sur f aces of our r oom. The cont r i but i on of t he r ef l ect ed sound f r om t he r oom t o t he meas ur ed f r equenc y r esponse can be as much as 60%. The meas ur ed r es ponse, as seen on t he char t , i s of t en t er med t he ‘ power r es pons e’ of our speaker s. The shape of t he l i ne nor mal l y ‘ dr oops’ t owar ds hi gh f r equenci es; t hi s i s due t o t he i nc r eas i ng di r ect i vi t y of our t weet er s as 20k Hz i s appr oached.
THI NGS A ROOM CORRECTI ON PRODUCT MUST DO Each l i ne on t he gr aph r epr esent s a measur ement at a di f f er ent angl e of f axi s. The char t shows 0, 30, 60 and 90 degr ee of f - axi s measur ement s. The r ed l i ne i s an est i mat i on of t he ‘ power r esponse’ , or what t he l i st ener hear s. These speaker s mai nt ai n ver y good of f axi s r esponse t hr ough 75 degr ees of f axi s.
THI NGS A ROOM CORRECTI ON PRODUCT MUST DO Above t he t r ansi t i on f r equency r oom cor r ect i on pr oduct s ar e act ual l y cor r ect i ng t he power r esponse of our speaker s i . e. t hey ar e appl yi ng speaker cor r ect i on. I n some cases t hi s can be a good t hi ng, f or exampl e wi t h l ower qual i t y speaker s t hat possess var i abl e on- axi s f r equency r esponse.
THI NGS A ROOM CORRECTI ON PRODUCT MUST DO I n most cases however , and especi al l y wi t h audi ophi l e qual i t y speaker s, one shoul d be hesi t ant about al l owi ng a r oom cor r ect i on pr oduct f r ee r ei gn t o det er mi ne and appl y cor r ect i on f i l t er s above t he t r ansi t i on f r equency. Some r easons f or t hi s ar e l i st ed bel ow: Equal i zi ng t he power r esponse wi l l
t ypi cal l y cause t he di r ect f r equency r esponse t o r i se t owar ds 20kHz; your ni ce speaker s t hat measur e f l at onaxi s at 1m wi l l now exhi bi t a r i si ng f r equency r esponse!
Many speaker desi gner s pur posel y engi neer i n some mi nor devi at i ons i n t he
f r equency r esponse. Thi s i s of t en a subj ect i ve voi ci ng of t he sound but i s al so somet i mes r equi r ed t o cont r ol t he sound qual i t y i mpact of a dr i ver br eakup mode. An exampl e of t hi s i s t he BBC or ‘ Gundr y’ di p.
THI NGS A ROOM CORRECTI ON PRODUCT MUST DO These exampl es i l l ust r at e why any r oom cor r ect i on pr oduct shoul d ei t her : Onl y appl y cor r ect i on t o bass f r equenci es l i ke
Mer i di an.
OR Al l ow t he end user t o sel ect whi ch t he f r equency r ange
t o whi ch r oom cor r ect i on i s appl i ed l i ke TacT.
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Must al l ow t he user t o choose a t ar get f r equency r esponse
THI NGS A ROOM CORRECTI ON PRODUCT MUST DO Room cor r ect i on dev i ces ai m t o f i t t he measur ed f r equency r es pons e t o a nomi nal t ar get f r equency r esponse by appl y i ng c or r ec t i on f i l t er s. Ther e i s an el ement of pr ef er enc e i n t he s hape of t he t ar get cur ve, some peopl e pr ef er r i ng a r ul er f l at r esponse whi l st ot her s pr ef er a r i s i ng r es pons e i n t he bass whi ch adds a l i t t l e mor e wei ght t o mus i c . To some ext ent t hi s pr ef er ence i s i nf or med by t he v ol ume at whi ch a per son l i st ens t o musi c and t he s ound l ev el dependent nat ur e of our hear i ng. Thos e who l i s t en at l ower vol umes ( e. g. 70dB) may pr ef er a l i f t of up t o 10dB at 30Hz. See t hi s i nf or mat i on on t he Fl et c her Muns on c ur ves f or mor e i nf or mat i on.
THI NGS A ROOM CORRECTI ON PRODUCT MUST DO I n any event any r oom cor r ect i on devi ce shoul d ei t her : Al l ow t he user a wi de choi ce of t ar get f r equency
r esponses
Or Al l ow t he user t o manual l y ‘ dr aw’
t hei r t ar get f r equency r esponse. Any syst em t hat r equi r es t he user t o speci f y t he cor r ect i on f i l t er s ( e. g. Ri ves Audi o PARC, Z- Syst ems RDP- 1) i s ef f ect i vel y pr ovi di ng a l i mi t ed ver si on of t hi s capabi l i t y.
THI NGS A ROOM CORRECTI ON PRODUCT MUST DO Ther e ar e t hr ee addi t i onal cr i t er i a t hat a r oom cor r ect i on pr oduct shoul d have: - not per f or mi ng a needl ess anal og t o di gi t al conver si on - pr ovi di ng measur ement capabi l i t i es - pr ovi di ng f i l t er gener at i on capabi l i t i es
Di d you r eal i ze t hat r oom cor r ect i on can’ t f i x al l t he acoust i cal pr obl ems of your l i st eni ng r oom? Let us know your t hought s! Acoust i c f r ont i er s speci al i zes i n t he desi gn and cr eat i on of hi gh per f or mance home t heat er s and l i st eni ng r ooms f or audi o / vi deo ent husi ast s. Di scover Acoust i c Fr ont i er s’ audi o desi gn ser vi ces, acoust i c t r eat ment ser vi ces and hi gh end home t heat er acoust i cs sol ut i ons
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