|Seating positions would be from 15 feet from the short wall to close to the length of the long wall to the rear. Any idea what to expect along these seating positions? Would 2 subs with one positioned in the front and the other to the rear of the room improve things?
You mean in the 26x14x8 room, where the main speakers would be placed along the 14' wall and people would sit facing the short wall from 15' to 26'? So you have close to 11' of seating area for something like 3-4 rows of seating?
If that is the case, people at the rear of the room who are close to the walls would hear much more bass than others, maybe even to the point of discomfort. If it is multiple rows of seats, and you could adjust the positions of them by +-2ft, get a RS meter and some spot freq multiples of room mode (22, 44, 65hz) or the whole 20-80hz sleuth. Measure the response at the seating position and +-2ft. And then place seat at position with least bump/null.
Sub in front and back might put one sub too close in proximity to the rear listeners, giving them more bass. Its purpose would to cancel out some of the room modes by going push-push with the front sub. But YMMV.
|Approxiamately what level will the TN1220 and TN1225 be at 16Hz and 20Hz respectively given the room and seating considerations? The sub will be powered by an existing amplifier, what will be the difference without the "optimizer" box? Also, for mainly movies on dvd, hdtv, etc, how much use will the additional response below 20Hz be - will he be missing anything on the Jurassic Park films for example.
TN1225's low end resp is probably around 22hz. W/O the optimizer box, its low end resp would be down an additional 6dB @ 25hz. That would make it down -7dB according to specs, you would get a bump @ 22hz, so that might help its response in 20-25hz region. With TN1220, it be -7dB @ 18hz, don't know how much room gain would help at that freq, but it will help in the 20-25hz region.
W/O the optimizer box, freq below port tuning will not be rolled off, so ultra low freq below it of any significance might cause the sub to bottom out. It would probably be better off to have the optimizer box and the TN1225. Most movies' impact occur in the 30-40hz region, there might be a few with the ultra low freq in the 20hz region. Those with <20hz signal are nowhere near 0dBFS for it to really affect you.