Sarhento and Bass addict, first, you should check my signature in order to have some info on my installation.
check this one first: http://www.blu-ray.com/community/gallery.php?member=Gelli
Once there, you'll see a chart showing a Hz by Hz Frequency Response made at the MLP.
the measurements were done exactly where my ears are positioned, which is the same i used
for Audyssey calibration.
i don't know exactly what makes the response so strong below 16 Hz.
it is most probably caused by many factors.
the measuring instrument i used has a flat Fr. response setting); meaning
no low frequency attenuation in the measurements.
one thing that isn't told is that the smaller sub is tuned at 16 Hz
and the larger one at 10 Hz:
for a given signal, the output of the smaller sub has been decreased to compensate
for it's lower max. output capability, in order that when both subs are driven hard,
the smaller one is not overloaded. i tuned for a difference of about 5 dB between the two.
i've tuned the 13-U like this:
2 ports blocked;
filter set at "sealed".
in the AVR config, after Audyssey calibration, the subs are set to play 3 dB hot, for a flat-to-the-ear response.
playing the loudest movies at reference level or Cameron Carpenter's Revolutionary on SACD, i never hear port chuffing from
the subs, and no distortion that i can hear.
before tuning this way, i asked Jack Gilvey for his opinion about this way of doing it,
and he answered: "I’d go with a 3-4 dB difference between the two as the PC13-Ultra will have at least that much advantage. Should be an outstanding setup! ".
Does not the manual say that "2 ports blocked" is not supported? I wonder why?
i'm not sure why, but i think it may be because under some conditions there will be port chuffing.
i don't get any of that on my 13-U because, along with the 12-Plus, i have spare output; they never work to full capacity.
when i only had the 12-Plus, i did have some chuffing sometimes when i tried to use it when tuned to 11 Hz.
Edited by Gellidius - 5/19/13 at 12:52pm