 Voice @-@ recording sessions were supervised by Pattillo and the Andersons , with Sylvia Anderson in charge of casting . Dialogue was recorded once per month at a rate of two scripts per session . Supporting parts were not pre @-@ assigned , but negotiated by the cast among themselves . Two recordings would be made at each session : one to be converted into electronic pulses for the puppet filming , the other to be added to the soundtrack during post @-@ production . The tapes were edited at Gate Recording Theatre in Birmingham . 
 Voice @-@ recording sessions <a href='uninflect' title='1'><mark>were</mark></a> supervised by Pattillo and the Andersons , with Sylvia Anderson in charge of casting . Dialogue was recorded once per month at a rate of two scripts per session . Supporting parts <a href='negative_concord' title='2'><mark>were</mark></a> <a href='negative_concord' title='3'><mark>not</mark></a>pre @-@ assigned , but negotiated by the cast among themselves . Two recordings would be made at each session : one to be converted into electronic pulses for the puppet filming , the other to be added to the soundtrack during post @-@ production . The tapes <a href='uninflect' title='4'><mark>were</mark></a> edited at Gate Recording Theatre in Birmingham . 
Voice @-@ recording sessions was supervised by Pattillo and da Andersons , wid Sylvia Anderson in charge of casting . Dialogue was recorded once per month at a rate of two scripts per session . Supporting parts ain't pre @-@ assigned , but negotiated by tdacast among themselves . Two recordings would b made at each session : one to bbconverted into electronic pulses for the puppet filming , the other to bebdded to the soundtrack during post @-@ production . The tapes was edited at Gate Recording Theatre in Birmingham .