[spirit]

Hey Georgia,
I wonder if I can resurrect the X-curve as a topic? From my reading, the X-curve came about because film mixes in theatres were perceived as overly bright. The mixes were bright because the high frequency decay (RT60) of a room increases with room volume; if the film was mixed in a smaller room, and subsequently screened in a room of substantially larger volume, voila, a bright/ even harsh mix is heard unless the X-curve is inserted into the theatre's playback system.
It is common practice to insert the X-curve (aka Film curve) during a mix into the monitoring chain at a dub stage, because the room size is comparable to the theatre, and the theatre uses the curve- not because the acoustic properties of the two rooms are different.
If mixes are prepared in a smaller room, the physical properties of the room will reduce the high frequency reverberation time according to the Sabine equation (RT=(0.049*volume/ abs), where 'abs' is absorbance in Sabines at the given frequency). This will in effect, add an 'acoustic' X-curve to the room. If further high frequency roll-off is added through an X-curve EQ on the monitoring chain, during mixdown, an overly bright/ harsh mix will be heard in the theatre.
We have in fact been hearing this phenomenon in theatrical mixes coming out of our room, which has a much smaller volume, than a typical dub stage (yes, we do preview the mix at a full sized stage). We have now removed the X-curve to suit our smaller room, with good results.
I am beginning to think that the X-curve, is something that needs to be applied thoughtfully, based on the mix environment.
Are you able to comment on this? Thanks so much!

Tim Runzer