 Independiente marked Arjona 's fourth collaboration with Torres . The latter was a composer and producer , also receiving background @-@ vocal credit . The musicians first worked together in 2005 , when Arjona released his tenth studio album ( Adentro ) . He stated that he first " tested " Torres by sending him the " hookiest and darkest tracks " on the album : " Acompañame A Estar Solo " and " Iluso " . Torres then " went all out on the first demo , hiring a full band that included a string orchestra " . In Quién Dijo Ayer ( 2007 ) , Torres produced the singles " Quién " and " Quiero " and provided background vocals on the remastered versions of Arjona 's past hits . In 5to Piso ( 2008 ) , Torres produced several tracks ; one was the lead single " Como Duele " , considered Arjona 's " biggest hit in years " by Jason Birchmeier of Allmusic . 
 Independiente marked Arjona <a href='null_genetive' title='1'><mark>'s</mark></a>fourth collaboration with Torres . The latter was a composer and producer , also receiving background @-@ vocal credit . The musicians first worked together in 2005 , when Arjona released his tenth studio album ( Adentro ) . He stated that he first " tested " Torres by sending him the " hookiest and darkest tracks " on the album : " Acompañame A Estar Solo " and " Iluso " . Torres then " went all out on the first demo , hiring a full band <a href='null_relcl' title='2'><mark>that</mark></a>included a string orchestra " . In Quién Dijo Ayer ( 2007 ) , Torres produced the singles " Quién " and " Quiero " and provided background vocals on the remastered versions of Arjona <a href='null_genetive' title='3'><mark>'s</mark></a>past hits . In 5to Piso ( 2008 ) , Torres produced several tracks ; one was the lead single " Como Duele " , considered Arjona <a href='null_genetive' title='4'><mark>'s</mark></a>" biggest hit in years " by Jason Birchmeier of Allmusic . 
Independiente marked Arjona  fourth collaboration with Torres . da latter was a composer and producer , also receiving background @-@ vocal credit . Tdamusicians first worked together in 2005 , when Arjona released his tenth studio album ( Adentro ) . He stated that he first " tested " Torres by sending him thda hookiest and darkest tracks " on the mixtape : " Acompañame A Estar Solo " and " Iluso " . Torres then " went all out on the first demo , hiring a full band included a string orchestra " . In Quién Dijo Ayer ( 2007 ) , Torres produced the singles " Quién " and " Quiero " and provided background vocals on the remastered versions of Arjona  past hits . In 5to Piso ( 2008 ) , Torres produced several tracks ; one was the lead single " Como Duele " , considered Arjona  " biggest hit in yrs " by Jason Birchmeier of Allmusic .