kach22i said:
FYI:
Hey, I just got my Cardas interconnects and in the associated paperwork is a bit about "plannar speaker" placement. Take the .618 (no I'm not leaving the "1" out buy accident like you did - not a dig) and multiply by Ceiling Height to get placement to rear wall (I think). Anyway, I'm sure this is all on the Cardas site, I just did not notice this before - cheers.
Kach22i,
Thanks for all your posts on this thread. My current speakers feature a ribbon tweeter and planar magnetic midranges but their back wave is damped. This facilitates placement close to the rear wall, thankfully because the speakers need the wall for bass reinforcement. Alas it ruins the purity of the midrange and treble because of cavity resonances along with distortion and impulse degradation from the reflected rear wave. I really think the only good implementations of planar drivers are full dipole and transmission line loading.
I would definitely relocate the absorption panels behind the speakers to the opposite wall should any dipole (including the E2) take residence in my room. I have owned dipoles before, specifically the Apogee Diva, and have a pretty good idea on what they like in terms of room placement. Cardas bases their 0.618 x ceiling height recommendation on the fact that dipoles minimize side wall reflections. However in my room with 10' ceiling, 6+ ft away from the wall is not necessary. From my experience with the Apogees, and also placement recommendations from M-L, Apogee, Magnepan, Soundlab, etc. 3-4 ft is a reasonable distance. That allows enough space for the reflected sound is sufficienty delayed, while also preventing most cancellation in the bass region. With the expected placement of the E2 in my room, with toe in the electrostatic panel (which I would put on the inside) would be 40-46" out from the wall, with the apex of the curve 44" out.
The curtains are there for the long haul, as wife spent $5k on them
and likes the way they look. They are retractable, and if the room is too dead I could pull them back to expose painted drywall during serious listening.
The quarter round bass traps I now have are far too small to be of any use. They don't do any harm so I've left them up. With the bass towers of the E2 in the front corners, I would either have to purchase large round traps to control my standing waves (mainly 40hz and 70hz) or, more likely, rely on DSP correction.
Currently I'm trying to figure out if the EXOS crossover supplied with the E2 provides significant bass equalization, in addition to controls for phase, crossover frequency (60-90), and bass output level. I've been told that the "high" output of the E2 is basically just a pass through to the main amp, which then sends a full range signal to the passive crossovers incorporated into the dipole tower bases. The sub-bass towers are bipole rather than dipole (which would require a lot of equalization). Since the 12" woofers are in fairly small enclosure which appear to be sealed, some EQ is probably needed in the bottom octave. Maybe there is a Linkwitz transform in the E2's EXOS. In my smallish room, which has about 12dB/octave bass gain below 33hz, probably only a small amount of EQ will be needed to have flat in-room response to 20hz.
If there is none or only a small amount of EQ from the EXOS, The TacT RCS 2.2X would replace it, probably doing a much better job because it can implement zero phase FIR crossovers, while also facilitating perfect time alignment and room correction. Automatic time alignment of subs and main is faulty in the RCS, but with some external measuring software and a bit of math the exact delay can be measured and programmed. When the right alignment between the subs and mains is finally set, the result is quite stunning
