LGT TURNED TO NEW ASSIGNED HDG TOO SOON CAUSING LTSS.

Narrative

DEP CTL HAD US ON A 335 DEG HDG TO PARALLEL THE 335 DEG RADIAL OF DEN VORTAC. AFTER HDOF TO ZDV; CLRED TO FL230. AT APPROX FL190 WE RECEIVED A CLRNC OF DIRECT TO LARAMIE AND CLB TO FL310. CAPT STARTED A L TURN TO GO DIRECT LAR. AT APPROX FL200 CTR SAID 'CONFIRM CLRED DIRECT LAR AT FL210.' RESPONSE WAS; ROGER; DIRECT LAR AT FL210. CTR THEN SAID TURN R 15 DEGS. APPARENTLY PORTIONS OF THE RADIO XMISSIONS WERE BLOCKED OR INTERRUPTED AS WE DID NOT RECEIVE ALL OF THE CLRNCS; DUE TO CONGESTION ON THE FREQ. SO DID NOT HEAR THESE PORTIONS OF THE RADIO XMISSIONS; AS HE WAS OCCUPIED WITH TALKING TO CABIN CREW ON THE INTERPHONE REGARDING THE CABIN TEMP. CONTRIBUTING FACTORS TO THIS SIT WERE THE DIFFICULTY IN UNDERSTANDING THE ATC CTLRS DUE TO VARIED VOLUME AND BACKGND NOISES ON THE RADIOS AND CONGESTION ON THE FREQ. SUPPLEMENTAL INFO FROM ACN 238722: ZDV ASKED US TO CONFIRM THAT WE WERE CLRED DIRECT LARAMIE UPON PASSING FL210. WE RESPONDED; 'OK; CLRED DIRECT LARAMIE ABOVE FL210.' THE CONFUSION IN CLRNCS RESULTED FROM 2 SOURCES. THE RADIO VOLUME NEEDED ADJUSTMENT EACH FREQ CHANGE; AND THE ZDV FREQ WAS CONGESTED. IT IS POSSIBLE THAT PART OF ATC'S XMISSION WAS BLOCKED OUT. WHEN WE FINALLY RECEIVED THE PROPER CLRNC; DIRECT LARAMIE ABOVE FL210; ZDV MAY HAVE INTERPRETED OUR RESPONSE INCORRECTLY. WE WERE ACKNOWLEDGING THAT CLRNC; BUT NOT REAFFIRMING A PREVIOUS CLRNC. SUPPLEMENTAL INFO FROM ACN 239573: APPARENT ACFT SEPARATION WAS LOST.