SMPTE X-curve Calibrated Dub-stages

The number of mixers compensating for the SMPTE X-curve in the higher frequencies coincides with Figure 3.9 and with the fact that 14 mixers rated high frequency response at or below average and 10 mixers rating clarity of dialog at or below average. Figure 3.10 shows that low frequency response was rated at or below average by 11 mixers, though only 1 mixer stated using any compensation in the lower frequencies. This may point towards a hesitancy to increase lower frequency which could make the mix "muddy" and further reduce dialog clarity. The high level of variability in X-curve compensation amongst mixers undermines translation, the corner stone of the SMPTE Standard.

Though a majority of mixers claim to use some type of compensation when mixing to the X- curve, a vast majority of them (83%) felt that the translation of their final mix from the dub-

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stage to a commercial cinema was above average to excellent. This number is mirrored by the quantity of mixers (80%) who rated the overall sonic quality of their dub-stage above average to excellent. This may be due to the mixers' years of experience in working in SMPTE calibrated rooms and learning to translate their work from dub-stage to cinema. There may also be some type of adaptation in process involved that allows mixers to adjust to the response curve their room has been tuned to.

From the survey data, it can be noted that 67% of mixers who had 26 to 40 years of experience rated their dub-stage to cinema translation above average to excellent, whereas 61% of mixers with 11 to 25 years and 46% of mixers with 1 to 10 years rated translation the same way. There is a question as to whether these descending experience-related percentages can be attributed to the skill of the mixer with regards to translation, adaptation or even hearing loss. Considering that mixers who have spent 26 to 40 years in a high volume dub-stage for long hours would make hearing loss an extremely plausible reason for being content with translation.

Half of the mixers surveyed spend at least 80% of their time working in a SMPTE ST202 calibrated dub-stage. Only 3 mixers spend the same percentage of work time in a "modified" SMPTE X-curve room. In stark contrast, of the few mixers who work in rooms calibrated to a "house" curve, working in such a dub-stage represents very little of their overall work time. However, of those who work primarily in SMPTE calibrated dub-stages, approximately half of them admitted that here are two-stages of equalization available in the B-chain; one for when the room is being calibrated and the other to be used at the discretion of the mixer. Again, this type of variability does not lend well to translation as the standard had intended and questions whether mixers feel that the X-curve is actually hindering translation in some way.

Figure 3.8 shows that for those who work on the two largest sized dub-stage (at or larger than 21m x 15m x 9m) spend a majority of their time on a stage calibrated to the SMPTE X-curve. This is not surprising as most, if not all, of the large stages started as film-based stages which typically necessitated Dolby Certification in order to print master in any of the Dolby encoding schemes. To obtain Dolby Certification, the dub-stage had to be tuned to the SMPTE X-curve by a Dolby licensed technician. The connection between Dolby and the SMPTE X-curve is covered in section 2.2.

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It might seem counterintuitive to find that 60% of the work carried out on some of the smaller dub-stages was completed in X-curved tuned rooms. These rooms are typically too small to be film rooms and therefore do not share the same requirements of the larger stages. However, as the costs to build large stages went up as post-production budgets went down, there were requirements to build smaller dub-stages that could complete cinematic work. On some occasions, dub-stages reserved for television mixing were repurposed into film stages. Being built or repurposed for film work, these smaller rooms were required to be tuned to the X-curve. 3.5.2 "Modified" SMPTE X-curve Dub-stages

The mixers who work on "modified" X-curve dub-stages (not inclusive of those who were not sure) were asked if they knew how and why their stages were modified. Of these 12 mixers, 7 replied that the modifications were made to the high frequency range typically to create a "less severe" high end roll off than the standard SMPTE X-curve. The other 5 mixers knew only that their stage had been modified in order to improve sonic performance but were not sure how the modifications took form. When asked about translation, none of these mixers stated that they had any problems with their mixes playing back correctly in commercial cinemas.

3.5.3 "House" Curve Calibrated Dub-stages

Of the 6 mixers who work on a "house" calibrated dub-stage, 4 stated that less high frequency roll off than the X-curve and no low frequency roll off were used to calibrate the stages they work on. Two other mixers stated that the "house" curve used was client specific. These mixers offered no comments on the quality of translation between their dub-stage and the commercial cinemas.