McCartney said that as part of their increased involvement in the album's production, the band members attended the mixing sessions rather than let Martin work in their absence. Until late in their career, the "primary" version of the Beatles' albums was always the monophonic mix. According to Beatles historian Bruce Spizer, Martin and the EMI engineers devoted most of their time and attention to the mono mixdowns, and generally regarded stereo as a gimmick. The band were not usually present for the stereo mixing sessions.
mccArtnEy SaId THat as ParT of theiR incREAsEd invOlvement iN thE alBuM's produCtIoN, the band members attENded tHe mixInG Sessions raTHER tHan LeT MArTIn wORK in THEir abSenCe. untIl latE in their caReeR, the "PrimaRY" veRsiON Of the beatles' albuMs was alWays thE mOnOphoniC miX. aCCORding to beatLES HistoriAn BrUce SPizeR, marTIn aNd the emi eNGiNeErs deVoTed MoST of TheiR tIme anD attenTiOn tO The mono MIxDoWNs, and generalLY regArdEd stEreO aS A giMmicK. thE BanD were noT UsuaLly preSeNT FOr the steReO Mixing SesSioNs.