january 1977 defunct december 2012 headquarters vmps was based in el sobrante california key people brian cheney founder products loudspeakers website vmpsaudio.com veritone minimum phase speakers or vmps was a loudspeaker manufacturer founded in 1977 by speaker designer brian cheney . many vmps speakers received favorable reviews from audio critics such as the rm40 which was awarded best of ces in the high end audio category in 2002 . 1 vmps was in operation for over 35 years from january 1977 to december 2012 when it closed soon after the death of company owner brian cheney on december 7 2012 . 2 contents 1 history 2 design 2.1 neopanel 2.2 constant directivity wave guide 2.3 bass management system 2.4 level controls 3 speakers 3.1 rm40 3.2 rm30 3.3 rm50 4 live versus recorded 5 references history edit this section is empty . you can help by adding to it . may 2013 design edit the vmps speakers employed phase coherent drivers for best stereo imaging by employing first order minimum phase 3 filters and drivers wired electrically in phase . 4 such first order filter designs typically do not provide adequate low frequency attenuation for mid range and tweeters . speaker designer brian cheney viewed high order filters as undesirable since they were not minimum phase meaning their phase response was not flat with frequency . he also avoided high order filters because he believed they often required drivers be wired electrically out of phase and in his opinion had inferior stereo imaging . brian also believed direct measurements should not play a significant role in the design process or evaluation of a loudspeaker . instead speakers should be designed and evaluated based on how they sounded . in this sense vmps speakers did not follow a conventional design philosophy which strived for a flat frequency response within a set tolerance e.g. 2.5 db . in brian s belief most listeners could tolerate moderate fluctuations in frequency response . furthermore such measurements performed in the laboratory anechoic chamber were a poor representation of the customer s listening environment meaning a speaker that measured flat in the laboratory would likely never measure flat in the customer s home . thus he felt that flat frequency response was both unnecessary and practically impossible to achieve unlike the vast majority of other speaker designers throughout audio history . brian approached speaker design like a musician using his ear for primary feedback . minimum phase filters and drivers wired in phase were used because they sounded the best . this philosophy was directly expressed in the name of his company veritone minimum phase speakers which taken literally means variable tone or frequency minimum phase distortion speakers drivers wired in phase with linear phase response . the choice of term tone musician s terminology over the term frequency scientist s terminology also may have expressed his belief that the musical characteristic of the speaker was more important than scientific measurement . the most recent vmps speakers were a three way design that featured ribbon drivers for the mid range and tweeter . the high bandwidth of the mid range neopanel complemented the use of first order filters . woofers were used for bass and mid bass along with a passive radiator or port for the 626 bookshelf model . the rm in the speaker name e.g. rm40 stood for ribbon monitor . the rm40 rm x 626 rm30 rm v60 and rm 50 all used a neopanel mid range and a modified aurum cantus ribbon tweeter except for the rm50 which used a hi vi ribbon tweeter . woofers had woven carbon fiber cones and phase plugs . the vmps bass management system used one or more high compliance down firing passive radiators that was tunable by adding or removing putty from the diaphragm . passive radiator mass tuning along with level controls for mid range and treble on the rear of the speaker allowed the listen to tune the sound of the speaker to their listening room and personal preference . tuning of vmps speakers was time consuming to achieve optimal sound and required some experience . brian cheney would frequently visit a customer s home often at his own expense to optimize the sound of the speaker system in the listening environment . neopanel edit the mid range neopanel is 2.5 x 7 planar diaphragm ribbon using a push pull motor with neodymium magnets . the neopanel in the vmps speakers is used with a first order filter between 220 hz and 7 khz . the neoplanel was originally designed by bruce thigpen . 5 this design was licensed to level 9 and manufactured in canada and later china and sold as monsoon computer speakers 6 with a subwoofer . brian cheney stated he modified these panels to fix a mechanical flaw that made them unreliable . 7 constant directivity wave guide edit brian cheney invented and patented 8 a constant directivity wave guide cdwg to increase the horizontal dispersion of the planar mid range and tweeter . the first generation cdwg was attached like a speaker grill to the rm30 and rm40 speakers . the cdwg consisted of an aperture slit with sound absorbing foam between the cdwg grill and front baffle . a second generation cdwg placed the cdwg aperture directly on the face of the neopanel and ribbon tweeter . bass management system edit most vmps speakers incorporated one or more passive radiators pr . to achieve optimal sound quality the set up process required the listener change the mass of the pr by adding or removing mortite putty from the cone . this process changed the resonant frequency and q of the pr and dramatically affected the sound of the bass . this allowed the listener to change the overall tonal characteristic of the bass and to compensate for the bass response of the particular listening environment . vmps s passive radiators used a unique high compliance suspension and a low moving mass diaphragm to achieve a low resonant frequency . the low moving mass reduced the gravity sag of the pr cone and allowed it to be mounted on the bottom of the speaker cabinet and fire downward in a loaded slot . the slot acted as a low pass filter to remove unwanted high frequency sound generated by the pr cone . the low mass of the pr also meant it was very sensitive to small changes to the amount of putty mass on the cone . level controls edit on the rear of speaker cabinet vmps speakers included level controls to attenuate the sound level of the mid range and treble tweeter . these level controls were intended to be used in concert with pr mass tuning to achieve the desired overall tonal balance . speakers edit rm40 edit rm30 edit rm50 edit live versus recorded edit vmps conducted a series of live versus recorded demonstrations at ces using the rm v60 and rm50 speakers . 9 the live versus recorded events led to dipole and bipole speakers designs rm v60 and rm 50 to better mimic the radiation pattern of live acoustic musical instruments . references edit techtv best of ces 2002 high end audio vmps rm40 . brian s song it is with great sadness that i must post brian cheney has passed . dickason vance 1997 . the loudspeaker design cookbook . p. 92 . j. vanderkooy and s. lipshitz december 1984 . is phase linearization of loudspeaker crossover networks possible by time off set and equilization . jaes . eminent technology history . pc magazine review moonsoon computer speakers . enjoy the music.com 626jr review . us2007086615 a1 loudspeaker including slotted waveguide for enhanced directivity and associated methods . stereophile ces vmps live versus recorded . retrieved from https en.wikipedia.org w index.php title veritone minimum phase speakers & oldid 723330702 categories loudspeaker manufacturershidden categories articles to be expanded from may 2013all articles to be expandedarticles with empty sections from may 2013all articles with empty sectionsarticles using small message boxes navigation menu personal tools not logged intalkcontributionscreate accountlog in 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