I was playing around with REW on the weekend, making a new curve for listening to music. I do all my REW testing with the Denon 3803 in stereo mode with speakers set to small.
I tweaked the sub distance setting to get the smoothest response around the crossover frequency. I then switched over to DPL2 cinema and ran a sweep, the results were not pretty. I tried DTS neo6 and got the same results, a large hump around 120hz and a big dip at 100hz.
I tried the PL2 music mode and the results were different again but closer to Stereo than DPL2c.
The first graph below shows DPL2c(blue) vs Stereo(green). The second graph shows the bass response of DPL2 cinema(brown) vs DPL2 music(blue).
(the curve used in the graph is my movie preset, not music.)
I'm assuming these surround modes (DPL2c and DTSneo6) use a different crossover or add some EQ into the signal, I'm leaning towards the crossover being different.
After discovering this my first thought was what if the Dolby Digital EX mode uses the same crossover/EQ as the DPL2c - that would mean all my curves are wrong, but after some testing it seems this is not the case, Dolby 5.1 gives the same results as the stereo curve (I tested this manually using a test DVD and SPL meter like in the old days
).
I'll just add that my AVR does not have room EQ or DPL2x. I would be interested to see the results with DPL2x.
Hakka.
stereovspl2c.jpg dpl2cvsdpl2m.jpg